# kb

id: taxonomy-20260505-2
file: data/en.wikipedia.org/wiki/Taxonomy-2.md
category: reference
title: Taxonomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Taxonomy
date_saved: 2026-05-05T07:13:29.818243+00:00
instance: kb-cron
parent: taxonomy-20260505-0
summary:
Two of the predominant types of relationships in knowledge-representation systems are predication and the universally quantified conditional. Predication relationships express the notion that an individual entity is an example of a certain type (for example, John is a bachelor), while universally quantified conditionals express the notion that a type is a subtype of another type (for example, "A dog is a mammal", which means the same as "All dogs are mammals"). The "has-a" relationship is quite different: an elephant has a trunk; a trunk is a part, not a subtype of elephant. The study of part-whole relationships is mereology. Taxonomies are often represented as is-a hierarchies where each level is more specific than the level above it (in mathematical language is "a subset of" the level above). For example, a basic biology taxonomy would have concepts such as mammal, which is a subset of animal, and dogs and cats, which are subsets of mammal. This kind of taxonomy is called an is-a model because the specific objects are considered as instances of a concept. For example, Fido is-an instance of the concept dog and Fluffy is-a cat. In linguistics, is-a relations are called hyponymy. When one word describes a category,


id: taxonomy-20260505-3
file: data/en.wikipedia.org/wiki/Taxonomy-3.md
category: reference
title: Taxonomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Taxonomy
date_saved: 2026-05-05T07:13:29.818243+00:00
instance: kb-cron
parent: taxonomy-20260505-0
summary:
=== Logical and rationalist approaches === Logical division, or logical partitioning (top-down classification or downward classification) is an approach that divides a class into subclasses and then divide subclasses into their subclasses, and so on, which finally forms a tree of classes. The root of the tree is the original class, and the leaves of the tree are the final classes. Plato advocated a method based on dichotomy, which was rejected by Aristotle and replaced by the method of definitions based on genus, species, and specific difference. The method of facet analysis (cf., faceted classification) is primarily based on logical division. This approach tends to classify according to "essential" characteristics, a widely discussed and criticized concept (cf., essentialism). These methods may overall be related to the rationalist theory of knowledge. Michelle Bunn notes that logical partitioning uses categories which are established a priori; data is then collected and used to test the extent to which the classification system can be sustained. === Empiricist approaches === "Empiricism alone is not enough: a healthy advance in taxonomy depends on a sound theoretical foundation" Phenetics or numerical taxonomy is by contrast bottom-up classification, where the starting point is a set of items or


id: taxonomy-20260505-4
file: data/en.wikipedia.org/wiki/Taxonomy-4.md
category: reference
title: Taxonomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Taxonomy
date_saved: 2026-05-05T07:13:29.818243+00:00
instance: kb-cron
parent: taxonomy-20260505-0
summary:
John Stuart Mill explained the artificial nature of the Linnaean classification and suggested the following definition of a natural classification:"The Linnæan arrangement answers the purpose of making us think together of all those kinds of plants, which possess the same number of stamens and pistils; but to think of them in that manner is of little use, since we seldom have anything to affirm in common of the plants which have a given number of stamens and pistils.""The ends of scientific classification are best answered, when the objects are formed into groups respecting which a greater number of general propositions can be made, and those propositions more important, than could be made respecting any other groups into which the same things could be distributed." "A classification thus formed is properly scientific or philosophical, and is commonly called a Natural, in contradistinction to a Technical or Artificial, classification or arrangement."Ridley (1986) provided the following definitions: "artificial classification. The term (like its opposite, natural classification) has many meanings; in this book I have picked a phenetic meaning. A classificatory group will be defined by certain characters, called defining characters; in an artificial classification, the members of a group resemble one another in


id: taxonomy-20260505-5
file: data/en.wikipedia.org/wiki/Taxonomy-5.md
category: reference
title: Taxonomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Taxonomy
date_saved: 2026-05-05T07:13:29.818243+00:00
instance: kb-cron
parent: taxonomy-20260505-0
summary:
Idiophones: instruments that rely on the body of the instrument to create and resonate sound. Membranophones: instruments that have a membrane that is stretched over a structure, often wood or metal, and struck or rubbed to produce a sound. The subcategories are largely determined by the shape of the structure that the membrane is stretched over. Chordophone: Instruments that use vibrating strings, which are most commonly stretched across a metal or wooden structure, to create sound. Aerophones Instruments that require air passing through, or across, them to create sound. Most commonly constructed of wood or metal. A fifth top category, Electrophones: Instruments that require electricity to be amplified and heard. This group was added by Sachs in 1940. Each top category is subdivided and Hornbostel-Sachs is a very comprehensive classification of musical instruments with wide applications. In Wikipedia, for example, all musical instruments are organized according to this classification. In opposition to, for example, the astronomical and biological classifications presented above, the Hornbostel-Sachs classification seems very little influenced by research in musicology and organology. It is based on huge collections of musical instruments, but seems rather as a system imposed upon the universe of instruments than as a system with


id: anatomical-terms-of-bone-20260505-0
file: data/en.wikipedia.org/wiki/Anatomical_terms_of_bone-0.md
category: reference
title: Anatomical terms of bone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_terms_of_bone
date_saved: 2026-05-05T07:13:32.882162+00:00
instance: kb-cron
parent: anatomical-terms-of-bone-20260505-0
summary:
Many anatomical terms descriptive of bone are defined in anatomical terminology, and are often derived from Greek and Latin. Bone in the human body is categorized into long bone, short bone, flat bone, irregular bone and sesamoid bone. == Types of bone == === Long bones === A long bone is one that is cylindrical in shape, being longer than it is wide. However, the term describes the shape of a bone, not its size, which is relative. Long bones are found in the arms (humerus, ulna, radius) and legs (femur, tibia, fibula), as well as in the fingers (metacarpals, phalanges) and toes (metatarsals, phalanges). Long bones function as levers; they move when muscles contract. === Short bones === A short bone is one that is cube-like in shape, being approximately equal in length, width, and thickness. The only short bones in the human skeleton are in the carpals of the wrists and the tarsals of the ankles. Short bones provide stability and support as well as some limited motion. === Flat bones === The term “flat bone” is something of a misnomer because, although a flat bone is typically thin, it is also often curved. Examples include the cranial


id: anatomical-terms-of-bone-20260505-1
file: data/en.wikipedia.org/wiki/Anatomical_terms_of_bone-1.md
category: reference
title: Anatomical terms of bone
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_terms_of_bone
date_saved: 2026-05-05T07:13:32.882162+00:00
instance: kb-cron
parent: anatomical-terms-of-bone-20260505-0
summary:
=== Walls === The following terms are used to describe the walls of a cavity: A labyrinth refers to the bony labyrinth and membranous labyrinth, components of the inner ear, due to their fine and complex structure. A sinus refers to a bony cavity, usually within the skull. == Joints == A joint, or articulation is the region where adjacent bones contact each other, for example the elbow, shoulder, or costovertebral joint. Terms that refer to joints include: articular process, referring to a projection that contacts an adjacent bone. suture, referring to an articulation between cranial bones. == Features of long bones == === Gross features === Bones are commonly described with the terms head, neck, shaft, body and base. The head of a bone usually refers to the proximal end of a long bone, but also refers to the distal end of metacarpals, metatarsals, and the ulna. The shaft refers to the elongated sections of long bone, and the neck the segment between the head and shaft (or body). The end of the long bone opposite to the head is known as the base. === Internal regions === === Internal and external === The cortex of a bone is


id: anatomical-terms-of-microanatomy-20260505-0
file: data/en.wikipedia.org/wiki/Anatomical_terms_of_microanatomy-0.md
category: reference
title: Anatomical terms of microanatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_terms_of_microanatomy
date_saved: 2026-05-05T07:13:34.068800+00:00
instance: kb-cron
parent: anatomical-terms-of-microanatomy-20260505-0
summary:
A histological scope of anatomical terminology describes structure, layout and position more precisely and mitigates ambiguity. An internationally accepted lexicon is Terminologia Histologica. == Layout == === Epithelia and endothelia === Epithelial cells line body surfaces, and are described according to their shape, with three principal shapes: squamous, columnar, and cuboidal. Squamous epithelium has cells that are wider than their height (flat and scale-like). Cuboidal epithelium has cells whose height and width are approximately the same (cube shaped). Columnar epithelium has cells taller than they are wide (column-shaped). Endothelium refers to cells that line the interior surface of blood vessels and lymphatic vessels, forming an interface between circulating blood or lymph in the lumen and the rest of the vessel wall. It is a thin layer of simple, or single-layered, squamous cells called endothelial cells. Endothelial cells in direct contact with blood are called vascular endothelial cells, whereas those in direct contact with lymph are known as lymphatic endothelial cells. Epithelium can be arranged in a single layer of cells described as "simple", or more than one layer, described as "stratified". By layer, epithelium is classed as either simple epithelium, only one cell thick (unilayered) or stratified epithelium as stratified


id: anatomical-terms-of-muscle-20260505-0
file: data/en.wikipedia.org/wiki/Anatomical_terms_of_muscle-0.md
category: reference
title: Anatomical terms of muscle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_terms_of_muscle
date_saved: 2026-05-05T07:13:35.226075+00:00
instance: kb-cron
parent: anatomical-terms-of-muscle-20260505-0
summary:
Anatomical terminology is used to uniquely describe aspects of skeletal muscle, cardiac muscle, and smooth muscle such as their actions, structure, size, and location. == Types == There are three types of muscle tissue in the body: skeletal, smooth, and cardiac. === Skeletal muscle === Skeletal muscle, or "voluntary muscle", is a striated muscle tissue that primarily joins to bone with tendons. Skeletal muscle enables movement of bones, and maintains posture. The widest part of a muscle that pulls on the tendons is known as the belly. ==== Muscle slip ==== A muscle slip is a slip of muscle that can either be an anatomical variant, or a branching of a muscle as in rib connections of the serratus anterior muscle. === Smooth muscle === Smooth muscle is involuntary and found in parts of the body where it conveys action without conscious intent. The majority of this type of muscle tissue is found in the digestive and urinary systems where it acts by propelling forward food, chyme, and feces in the former and urine in the latter. Other places smooth muscle can be found are within the uterus, where it helps facilitate birth, and the eye, where the pupillary sphincter


id: anatomical-terms-of-muscle-20260505-1
file: data/en.wikipedia.org/wiki/Anatomical_terms_of_muscle-1.md
category: reference
title: Anatomical terms of muscle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_terms_of_muscle
date_saved: 2026-05-05T07:13:35.226075+00:00
instance: kb-cron
parent: anatomical-terms-of-muscle-20260505-0
summary:
Synergist muscles also called fixators, act around a joint to help the action of an agonist muscle. Synergist muscles can also act to counter or neutralize the force of an agonist and are also known as neutralizers when they do this. As neutralizers they help to cancel out or neutralize extra motion produced from the agonists to ensure that the force generated works within the desired plane of motion. Muscle fibers can only contract up to 40% of their fully stretched length. Thus the short fibers of pennate muscles are more suitable where power rather than range of contraction is required. This limitation in the range of contraction affects all muscles, and those that act over several joints may be unable to shorten sufficiently to produce the full range of movement at all of them simultaneously (active insufficiency, e.g., the fingers cannot be fully flexed when the wrist is also flexed). Likewise, the opposing muscles may be unable to stretch sufficiently to allow such movement to take place (passive insufficiency). For both these reasons, it is often essential to use other synergists, in this type of action to fix certain of the joints so that others can be moved effectively,


id: anatomical-terms-of-muscle-20260505-2
file: data/en.wikipedia.org/wiki/Anatomical_terms_of_muscle-2.md
category: reference
title: Anatomical terms of muscle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_terms_of_muscle
date_saved: 2026-05-05T07:13:35.226075+00:00
instance: kb-cron
parent: anatomical-terms-of-muscle-20260505-0
summary:
Fusiform muscles have fibres that run parallel to the length of the muscle, and are spindle-shaped. For example, the pronator teres muscle of the forearm. Unipennate muscles have fibres that run the entire length of only one side of a muscle, like a quill pen. For example, the fibularis muscles. Bipennate muscles consist of two rows of oblique muscle fibres, facing in opposite diagonal directions, converging on a central tendon. Bipennate muscle is stronger than both unipennate muscle and fusiform muscle, due to a larger physiological cross-sectional area. Bipennate muscle shortens less than unipennate muscle but develops greater tension when it does, translated into greater power but less range of motion. Pennate muscles generally also tire easily. Examples of bipennate muscles are the rectus femoris muscle of the thigh, and the stapedius muscle of the middle ear. == State == === Hypertrophy and atrophy === Hypertrophy is increase in muscle size from an increase in size of individual muscle cells. This usually occurs as a result of exercise. == See also == == References == This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) Books Taber, Clarence Wilbur; Thomas, Clayton L.; Venes, Donald


id: anatomy-20260505-0
file: data/en.wikipedia.org/wiki/Anatomy-0.md
category: reference
title: Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomy
date_saved: 2026-05-05T07:13:36.446370+00:00
instance: kb-cron
parent: anatomy-20260505-0
summary:
Anatomy (from Ancient Greek ἀνατομή (anatomḗ) 'dissection') is the branch of morphology concerned with the study of the internal and external structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old science, having its beginnings in prehistoric times. Anatomy is inherently tied to developmental biology, embryology, comparative anatomy, evolutionary biology, and phylogeny, as these are the processes by which anatomy is generated, both over immediate and long-term timescales. Anatomy and physiology, which study the structure and function of organisms and their parts respectively, make a natural pair of related disciplines, and are often studied together. Human anatomy is one of the essential basic sciences that are applied in medicine, and is often studied alongside physiology. Anatomy is a complex and dynamic field that is constantly evolving as discoveries are made. In recent years, there has been a significant increase in the use of advanced imaging techniques, such as MRI and CT scans, which allow for more detailed and accurate visualizations of the body's structures. The discipline of anatomy is divided into macroscopic and microscopic parts. Macroscopic anatomy, or gross anatomy, is the examination of


id: anatomy-20260505-1
file: data/en.wikipedia.org/wiki/Anatomy-1.md
category: reference
title: Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomy
date_saved: 2026-05-05T07:13:36.446370+00:00
instance: kb-cron
parent: anatomy-20260505-0
summary:
=== Connective tissue === Connective tissues are fibrous and made up of cells scattered among inorganic material called the extracellular matrix. Often called fascia (from the Latin "fascia," meaning "band" or "bandage"), connective tissues give shape to organs and hold them in place. The main types are loose connective tissue, adipose tissue, fibrous connective tissue, cartilage and bone. The extracellular matrix contains proteins, the chief and most abundant of which is collagen. Collagen plays a major part in organizing and maintaining tissues. The matrix can be modified to form a skeleton to support or protect the body. An exoskeleton is a thickened, rigid cuticle which is stiffened by mineralization, as in crustaceans or by the cross-linking of its proteins as in insects. An endoskeleton is internal and present in all developed animals, as well as in many of those less developed. === Epithelium === Epithelial tissue is composed of closely packed cells, bound to each other by cell adhesion molecules, with little intercellular space. Epithelial cells can be squamous (flat), cuboidal or columnar and rest on a basal lamina, the upper layer of the basement membrane, the lower layer is the reticular lamina lying next to the connective tissue in


id: anatomy-20260505-2
file: data/en.wikipedia.org/wiki/Anatomy-2.md
category: reference
title: Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomy
date_saved: 2026-05-05T07:13:36.446370+00:00
instance: kb-cron
parent: anatomy-20260505-0
summary:
The body of a fish is divided into a head, trunk and tail, although the divisions between the three are not always externally visible. The skeleton, which forms the support structure inside the fish, is either made of cartilage, in cartilaginous fish, or bone in bony fish. The main skeletal element is the vertebral column, composed of articulating vertebrae which are lightweight yet strong. The ribs attach to the spine and there are no limbs or limb girdles. The main external features of the fish, the fins, are composed of either bony or soft spines called rays, which with the exception of the caudal fins, have no direct connection with the spine. They are supported by the muscles which compose the main part of the trunk. The heart has two chambers and pumps the blood through the respiratory surfaces of the gills and on round the body in a single circulatory loop. The eyes are adapted for seeing underwater and have only local vision. There is an inner ear but no external or middle ear. Low frequency vibrations are detected by the lateral line system of sense organs that run along the length of the sides of fish, and these


id: anatomy-20260505-3
file: data/en.wikipedia.org/wiki/Anatomy-3.md
category: reference
title: Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomy
date_saved: 2026-05-05T07:13:36.446370+00:00
instance: kb-cron
parent: anatomy-20260505-0
summary:
Reptiles are a class of animals comprising turtles, tuataras, lizards, snakes and crocodiles. They are tetrapods, but the snakes and a few species of lizard either have no limbs or their limbs are much reduced in size. Their bones are better ossified and their skeletons stronger than those of amphibians. The teeth are conical and mostly uniform in size. The surface cells of the epidermis are modified into horny scales which create a waterproof layer. Reptiles are unable to use their skin for respiration as amphibians do and have a more efficient respiratory system drawing air into their lungs by expanding their chest walls. The heart resembles that of the amphibian but there is a septum which more completely separates the oxygenated and deoxygenated bloodstreams. The reproductive system has evolved for internal fertilization, with a copulatory organ present in most species. The eggs are surrounded by amniotic membranes which prevents them from drying out and are laid on land, or develop internally in some species. The bladder is small as nitrogenous waste is excreted as uric acid. Turtles are notable for their protective shells. They have an inflexible trunk encased in a horny carapace above and a plastron below. These


id: anatomy-20260505-4
file: data/en.wikipedia.org/wiki/Anatomy-4.md
category: reference
title: Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomy
date_saved: 2026-05-05T07:13:36.446370+00:00
instance: kb-cron
parent: anatomy-20260505-0
summary:
Mammals are a diverse class of animals, mostly terrestrial but some are aquatic and others have evolved flapping or gliding flight. They mostly have four limbs, but some aquatic mammals have no limbs or limbs modified into fins, and the forelimbs of bats are modified into wings. The legs of most mammals are situated below the trunk, which is held well clear of the ground. The bones of mammals are well ossified and their teeth, which are usually differentiated, are coated in a layer of prismatic enamel. The teeth are shed once (milk teeth) during the animal's lifetime or not at all, as is the case in cetaceans. Mammals have three bones in the middle ear and a cochlea in the inner ear. They are clothed in hair and their skin contains glands which secrete sweat. Some of these glands are specialized as mammary glands, producing milk to feed the young. Mammals breathe with lungs and have a muscular diaphragm separating the thorax from the abdomen which helps them draw air into the lungs. The mammalian heart has four chambers, and oxygenated and deoxygenated blood are kept entirely separate. Nitrogenous waste is excreted primarily as urea. Mammals are amniotes, and


id: anatomy-20260505-5
file: data/en.wikipedia.org/wiki/Anatomy-5.md
category: reference
title: Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomy
date_saved: 2026-05-05T07:13:36.446370+00:00
instance: kb-cron
parent: anatomy-20260505-0
summary:
Arthropods comprise the largest phylum of invertebrates in the animal kingdom with over a million known species. Insects possess segmented bodies supported by a hard-jointed outer covering, the exoskeleton, made mostly of chitin. The segments of the body are organized into three distinct parts, a head, a thorax and an abdomen. The head typically bears a pair of sensory antennae, a pair of compound eyes, one to three simple eyes (ocelli) and three sets of modified appendages that form the mouthparts. The thorax has three pairs of segmented legs, one pair each for the three segments that compose the thorax and one or two pairs of wings. The abdomen is composed of eleven segments, some of which may be fused and houses the digestive, respiratory, excretory and reproductive systems. There is considerable variation between species and many adaptations to the body parts, especially wings, legs, antennae and mouthparts. Spiders a class of arachnids have four pairs of legs; a body of two segments—a cephalothorax and an abdomen. Spiders have no wings and no antennae. They have mouthparts called chelicerae which are often connected to venom glands as most spiders are venomous. They have a second pair of appendages called pedipalps


id: anatomy-20260505-6
file: data/en.wikipedia.org/wiki/Anatomy-6.md
category: reference
title: Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomy
date_saved: 2026-05-05T07:13:36.446370+00:00
instance: kb-cron
parent: anatomy-20260505-0
summary:
Incredible feats were made during the third century BCE in both the digestive and reproductive systems. Herophilus discovered and described not only the salivary glands but also the small intestine and liver. He showed that the uterus is a hollow organ and described the ovaries and uterine tubes. He recognized that spermatozoa were produced by the testes and was the first to identify the prostate gland. The anatomy of the muscles and skeleton is described in the Hippocratic Corpus, an Ancient Greek medical work written by unknown authors. Aristotle described vertebrate anatomy based on animal dissection. Praxagoras identified the difference between arteries and veins. Also in the 4th century BCE, Herophilos and Erasistratus produced more accurate anatomical descriptions based on vivisection of criminals in Alexandria during the Ptolemaic period. In the 2nd century, Galen of Pergamum, an anatomist, clinician, writer, and philosopher, wrote the final and highly influential anatomy treatise of ancient times. He compiled existing knowledge and studied anatomy through the dissection of animals. He was one of the first experimental physiologists through his vivisection experiments on animals. Galen's drawings, based mostly on dog anatomy, became effectively the only anatomical textbook for the next thousand years. His work was


id: anatomy-20260505-7
file: data/en.wikipedia.org/wiki/Anatomy-7.md
category: reference
title: Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomy
date_saved: 2026-05-05T07:13:36.446370+00:00
instance: kb-cron
parent: anatomy-20260505-0
summary:
Before the modern medical era, the primary means for studying the internal structures of the body were dissection of the dead and inspection, palpation, and auscultation of the living. The advent of microscopy opened up an understanding of the building blocks that constituted living tissues. Technical advances in the development of achromatic lenses increased the resolving power of the microscope, and around 1839, Matthias Jakob Schleiden and Theodor Schwann identified that cells were the fundamental unit of organization of all living things. The study of small structures involved passing light through them, and the microtome was invented to provide sufficiently thin slices of tissue to examine. Staining techniques using artificial dyes were established to help distinguish between different tissue types. Advances in the fields of histology and cytology began in the late 19th century along with advances in surgical techniques allowing for the painless and safe removal of biopsy specimens. The invention of the electron microscope brought a significant advance in resolution power and allowed research into the ultrastructure of cells and the organelles and other structures within them. About the same time, in the 1950s, the use of X-ray diffraction for studying the crystal structures of proteins, nucleic acids,


id: axial-line-dermatomes-20260505-0
file: data/en.wikipedia.org/wiki/Axial_line_(dermatomes)-0.md
category: reference
title: Axial line (dermatomes)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Axial_line_(dermatomes)
date_saved: 2026-05-05T07:13:37.756459+00:00
instance: kb-cron
parent: axial-line-dermatomes-20260505-0
summary:
The axial line is the line between two adjacent dermatomes that are not represented by immediately adjacent spinal levels. Although dermatomes are shown to be discrete segments on dermatomal maps (like in the image opposite), they are in fact not; adjacent dermatomes overlap with one another. This is one of the reasons for the variety of different dermatomal maps proposed. However, at axial lines, adjacent dermatomes do not overlap. An example of an axial line would be the line between the S2 and L4 dermatomes on the calf. == References ==


id: axillary-joints-20260505-0
file: data/en.wikipedia.org/wiki/Axillary_joints-0.md
category: reference
title: Axillary joints
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Axillary_joints
date_saved: 2026-05-05T07:13:39.059857+00:00
instance: kb-cron
parent: axillary-joints-20260505-0
summary:
The axillary joints are two joints in the axillary region of the body, and include the shoulder joint and the acromioclavicular joint. == Shoulder joint == The shoulder joint also known as the glenohumeral joint is a synovial ball and socket joint. The shoulder joint involves articulation between the glenoid cavity of the scapula (shoulder blade) and the head of the upper arm bone (humerus) and functions as a diarthrosis and multiaxial joint. Due to the very loose joint capsule that gives a limited interface of the humerus and scapula, it is the most mobile joint of the human body. == Acromioclavicular joint == The acromioclavicular joint, is the joint at the top of the shoulder. It is the junction between the acromion (part of the scapula that forms the highest point of the shoulder) and the clavicle. It is a plane synovial joint. The acromioclavicular joint allows the arm to be raised above the head. This joint functions as a pivot point (although technically it is a gliding synovial joint), acting like a strut to help with movement of the scapula resulting in a greater degree of arm rotation. == References ==


id: bonwill-triangle-20260505-0
file: data/en.wikipedia.org/wiki/Bonwill_Triangle-0.md
category: reference
title: Bonwill Triangle
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bonwill_Triangle
date_saved: 2026-05-05T07:13:40.277512+00:00
instance: kb-cron
parent: bonwill-triangle-20260505-0
summary:
The Bonwill Triangle is a triangle formed by the contact point of the mandibular central incisors and the right and left mandibular condyles. == Description == The distance between those points is equal in most humans and amounts on average to about 10 cm. The triangle is therefore an equilateral triangle in those cases. William Gibson Arlington Bonwill (1833–1899) was the first to describe this. Two variants of the Bonwill Triangle have been described that differ in the exact location of the points on the condyles. In one the points are located on the articulating surfaces of the condyles whilst in the other they are located centrally within the heads of the mandible. == Application == In terms of practical application, the Bonwill Triangle is utilized in the construction and correct application of fixed articulators, which (in contrast to fully- and semi-adjustable articulators) are a type of articulator that does not allow for adjustments to imitate the specific movements of an individual's jaw. Instead, these articulators are designed to replicate the average movements of the jaw, and among others the Bonwill Triangle relationship is used to achieve this result. == See also == Frankfurt plane == References == == External


id: commissure-20260505-0
file: data/en.wikipedia.org/wiki/Commissure-0.md
category: reference
title: Commissure
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Commissure
date_saved: 2026-05-05T07:13:41.455791+00:00
instance: kb-cron
parent: commissure-20260505-0
summary:
A commissure () is the location at which two objects abut or are joined. The term is used especially in the fields of anatomy and biology. The most common usage of the term refers to the brain's commissures, of which there are at least nine. Such a commissure is a bundle of commissural fibers as a tract that crosses the midline at its level of origin or entry (as opposed to a decussation of fibers that cross obliquely). The nine are the anterior commissure, posterior commissure, corpus callosum, commissure of fornix (hippocampal commissure), habenular commissure, ventral supraoptic decussation, Meynert's commissure, anterior hypothalamic commissure of Gasner, and the interthalamic adhesion. They consist of fibre tracts that connect the two cerebral hemispheres and span the longitudinal fissure. In the spinal cord, there are the anterior white commissure, and the gray commissure. Commissural neurons refer to neuronal cells that grow their axons across the midline of the nervous system within the brain and the spinal cord. Commissure also often refers to cardiac anatomy of heart valves. In the heart, a commissure is the area where the valve leaflets abut. When such an abutment is abnormally stiffened or even fused, valvular stenosis results, sometimes


id: decussation-20260505-0
file: data/en.wikipedia.org/wiki/Decussation-0.md
category: reference
title: Decussation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Decussation
date_saved: 2026-05-05T07:13:42.634474+00:00
instance: kb-cron
parent: decussation-20260505-0
summary:
Decussation is used in biological contexts to describe a crossing (due to the shape of the Roman numeral for ten, an uppercase 'X' (decussis), from Latin decem 'ten' and as 'as'). In Latin anatomical terms, the form decussatio is used, e.g. decussatio pyramidum. Similarly, the anatomical term chiasma is named after the Greek uppercase 'Χ' (chi). Whereas a decussation refers to a crossing within the central nervous system, various kinds of crossings in the peripheral nervous system are called chiasma. Examples include: In the brain, where nerve fibers obliquely cross from one lateral side of the brain to the other, that is to say they cross at a level other than their origin. See for examples decussation of pyramids and sensory decussation. In neuroanatomy, the term chiasma is reserved for crossing of- or within nerves such as in the optic chiasm. In botanical leaf taxology, the word decussate describes an opposite pattern of leaves which has successive pairs at right angles to each other (i.e. rotated 90 degrees along the stem when viewed from above). In effect, successive pairs of leaves cross each other. Basil is a classic example of a decussate leaf pattern. In tooth enamel, where bundles of


id: fistula-20260505-0
file: data/en.wikipedia.org/wiki/Fistula-0.md
category: reference
title: Fistula
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fistula
date_saved: 2026-05-05T07:13:45.159599+00:00
instance: kb-cron
parent: fistula-20260505-0
summary:
In anatomy, a fistula (pl.: fistulas or fistulae ; from Latin fistula, "tube, pipe") is an abnormal connection (i.e. tube) joining two hollow spaces (technically, two epithelialized surfaces), such as blood vessels, intestines, or other hollow organs to each other, often resulting in an abnormal flow of fluid from one space to the other. An anal fistula connects the anal canal to the perianal skin. An anovaginal or rectovaginal fistula is a hole joining the anus or rectum to the vagina. A colovaginal fistula joins the space in the colon to that in the vagina. A urinary tract fistula is an abnormal opening in the urinary tract or an abnormal connection between the urinary tract and another organ. An abnormal communication (i.e. hole or tube) between the bladder and the uterus is called a vesicouterine fistula, while if it is between the bladder and the vagina it is known as a vesicovaginal fistula, and if between the urethra and the vagina: a urethrovaginal fistula. When occurring between two parts of the intestine, it is known as an enteroenteral fistula, between the small intestine and the skin it is known as an enterocutaneous fistula, and between the colon and the skin


id: fistula-20260505-1
file: data/en.wikipedia.org/wiki/Fistula-1.md
category: reference
title: Fistula
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Fistula
date_saved: 2026-05-05T07:13:45.159599+00:00
instance: kb-cron
parent: fistula-20260505-0
summary:
=== N: Diseases of the urogenital system === (N32.1) Vesicointestinal fistula (N36.0) Urethral fistula Innora:between the prostatic utricle and the outside of the body (N64.0) Fistula of nipple (N82) Fistulae involving female genital tract / Obstetric fistula (N82.0) Vesicovaginal fistula: between the bladder and the vagina (N82.1) Other female urinary-genital tract fistulae Cervical fistula: abnormal opening in the cervix (N82.2) Fistula of vagina to small intestine Enterovaginal fistula: between the intestine and the vagina (N82.3) Fistula of vagina to large intestine Rectovaginal: between the rectum and the vagina (N82.4) Other female intestinal-genital tract fistulae (N82.5) Female genital tract-skin fistulae (N82.8) Other female genital tract fistulae (N82.9) Female genital tract fistula, unspecified === Q: Congenital malformations, deformations and chromosomal abnormalities === (Q18.0) Sinus, fistula and cyst of branchial cleft Congenital preauricular fistula: A small pit in front of the ear. Also known as an ear pit or preauricular sinus. (Q26.6) Portal vein-hepatic artery fistula (Q38.0) Congenital fistula of lip (Q38.4) Congenital fistula of salivary gland (Q42.0) Congenital absence, atresia and stenosis of rectum with fistula (Q42.2) Congenital absence, atresia and stenosis of anus with fistula (Q43.6) Congenital fistula of rectum and anus (Q51.7) Congenital fistulae between uterus and digestive and urinary


id: foundational-model-of-anatomy-20260505-0
file: data/en.wikipedia.org/wiki/Foundational_Model_of_Anatomy-0.md
category: reference
title: Foundational Model of Anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Foundational_Model_of_Anatomy
date_saved: 2026-05-05T07:13:46.338803+00:00
instance: kb-cron
parent: foundational-model-of-anatomy-20260505-0
summary:
The Foundational Model of Anatomy Ontology (FMA) is a reference ontology for the domain of human anatomy. It is a symbolic representation of the canonical, phenotypic structure of an organism; a spatial-structural ontology of anatomical entities and relations which form the physical organization of an organism at all salient levels of granularity. FMA is developed and maintained by the Structural Informatics Group at the University of Washington. == Description == FMA ontology contains approximately 75,000 classes and over 120,000 terms, over 2.1 million relationship instances from over 168 relationship types. == See also == Terminologia Anatomica Anatomography == References == == External links == The Foundational Model of Anatomy Ontology The Foundational Model of Anatomy Browser - current (tested 14 October 2025) [tried 15 Dec 2025, didn't work] The Foundational Model of Anatomy Browser - Archived on Web Archive- Wayback machine - seems to contain only front page but non functional FMA Ontology Browser (Note: dead link, tested 14 October 2025)


id: list-of-terms-using-the-word-occipital-20260505-0
file: data/en.wikipedia.org/wiki/List_of_terms_using_the_word_occipital-0.md
category: reference
title: List of terms using the word occipital
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/List_of_terms_using_the_word_occipital
date_saved: 2026-05-05T07:13:47.505322+00:00
instance: kb-cron
parent: list-of-terms-using-the-word-occipital-20260505-0
summary:
The adjective occipital, in zoology, means pertaining to the occiput (rear of the skull). Occipital is a descriptor for several areas of animal and human anatomy. External occipital protuberance Internal occipital crest Greater occipital nerve Lesser occipital nerve Occipital artery Occipital bone Occipital bun Occipital condyle Occipital groove Occipital lobe Occipital plane Occipital pole Occipital ridge Occipital scales Occipital triangle Occipital vein Parieto-occipital sulcus PGO (Ponto-geniculo-occipital) waves Preoccipital notch == References ==


id: medial-umbilical-fold-20260505-0
file: data/en.wikipedia.org/wiki/Medial_umbilical_fold-0.md
category: reference
title: Medial umbilical fold
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Medial_umbilical_fold
date_saved: 2026-05-05T07:13:48.759233+00:00
instance: kb-cron
parent: medial-umbilical-fold-20260505-0
summary:
The medial umbilical fold is an elevation of the peritoneum (on either side of the body) lining the inner surface of the lower anterior abdominal wall formed by the underlying medial umbilical ligament (the obliterated distal portion of the umbilical artery) which the peritoneum covers. Superiorly, the two medial umbilical folds converge towards the midline to meet and terminate at the umbilicus. The unpaired midline median umbilical ligament lies medially to each medial umbilical fold; a lateral umbilical fold lies lateral to either medial umbilical fold. A supravesical fossa lies between the median umbilical fold and either medial umbilical fold on either side. A medial inguinal fossa lies between the median umbilical fold and lateral umbilical fold of the same side on either side. == References ==


id: anatomical-terms-of-neuroanatomy-20260505-0
file: data/en.wikipedia.org/wiki/Anatomical_terms_of_neuroanatomy-0.md
category: reference
title: Anatomical terms of neuroanatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_terms_of_neuroanatomy
date_saved: 2026-05-05T07:13:49.992851+00:00
instance: kb-cron
parent: anatomical-terms-of-neuroanatomy-20260505-0
summary:
This article describes anatomical terminology that is used to describe the central and peripheral nervous systems - including the brain, brainstem, spinal cord, and nerves. == Anatomical terminology in neuroanatomy == Neuroanatomy, like other aspects of anatomy, uses specific terminology to describe anatomical structures. This terminology helps ensure that a structure is described accurately, with minimal ambiguity. Terms also help ensure that structures are described consistently, depending on their structure or function. Terms are often derived from Latin and Greek, and like other areas of anatomy are generally standardised based on internationally accepted lexicons such as Terminologia Anatomica. To help with consistency, humans and other species are assumed when described to be in standard anatomical position, with the body standing erect and facing observer, arms at sides, palms forward. === Location === Anatomical terms of location depend on the location and species that is being described. To understand the terms used for anatomical localisation, consider an animal with a straight CNS, such as a fish or lizard. In such animals the terms "rostral", "caudal", "ventral" and "dorsal" mean respectively towards the rostrum, towards the tail, towards the belly and towards the back. For a full discussion of those terms, see


id: anatomical-terms-of-neuroanatomy-20260505-1
file: data/en.wikipedia.org/wiki/Anatomical_terms_of_neuroanatomy-1.md
category: reference
title: Anatomical terms of neuroanatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_terms_of_neuroanatomy
date_saved: 2026-05-05T07:13:49.992851+00:00
instance: kb-cron
parent: anatomical-terms-of-neuroanatomy-20260505-0
summary:
Axial or "transverse" or "horizontal", the plane that is horizontal and parallel to the ground with the body standing in the standard anatomical position. It contains (and thus is defined by) the lateral and the medial axes of the brain. Coronal, a vertical plane that passes through the coronal suture of the skull (or through both ears), or any plane parallel to this. There is no term "paracoronal" comparable to the commonly used "parasagittal". Sagittal, a vertical plane that passes from between the nostrils, and between the cerebral hemispheres, dividing the brain into left and right halves. "Median plane" specifically defines the midline between left and right sides of the body. It contains the dorsoventral and medial axes of the brain. A parasagittal plane is any plane parallel to the sagittal plane. == Nerves == === Function === Specific terms are used for peripheral nerves that originate from, or arrive at, a specific point. An afferent nerve fiber is a fibre originating at the present point. For example, a striatal afferent is an afferent originating at the striatum. An efferent nerve fiber is one that arrives at the present point. For example, a cortical efferent is a fibre coming from


id: neurolex-20260505-0
file: data/en.wikipedia.org/wiki/NeuroLex-0.md
category: reference
title: NeuroLex
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/NeuroLex
date_saved: 2026-05-05T07:13:51.339499+00:00
instance: kb-cron
parent: neurolex-20260505-0
summary:
NeuroLex is a lexicon of neuroscience concepts supported by the Neuroscience Information Framework project, which is funded by the NIH Blueprint for Neuroscience Research. It is the lexical part of the NIF knowledge base, and NeuroLex is intended to make literature review easier and ensure consistent terminology and usage across researchers for the topics of experimental, clinical, and transnational neuroscience, and for genetic and genomic resources. It is structured as a semantic wiki, using Semantic MediaWiki. NIF provides access to resources that are relevant to neuroscience, search strategies tailored to the field, and access to content that is traditionally "hidden" from web search engines. The Framework is an inventory of neuroscience databases, annotated and integrated with a unified system of biomedical terminology (i.e., NeuroLex). NIF supports concept-based queries across multiple scales of biological structure and multiple levels of biological function. As part of the NIF, a search interface to many different sources of neuroscience information and data is provided. To make this search more effective, the NIF is constructing ontologies to help organize neuroscience concepts into category hierarchies, e.g. stating that a neuron is a cell. This will allow users to perform more effective searches and to organize and understand


id: neuronames-20260505-0
file: data/en.wikipedia.org/wiki/NeuroNames-0.md
category: reference
title: NeuroNames
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/NeuroNames
date_saved: 2026-05-05T07:13:52.590276+00:00
instance: kb-cron
parent: neuronames-20260505-0
summary:
NeuroNames is an integrated nomenclature for structures in the brain and spinal cord of the four species most studied by neuroscientists: human, macaque, rat and mouse. It offers a standard, controlled vocabulary of common names for structures, which is suitable for unambiguous neuroanatomical indexing of information in digital databases. Terms in the standard vocabulary have been selected for ease of pronunciation, mnemonic value, and frequency of use in recent neuroscientific publications. Structures and their relations to each other are defined in terms of the standard vocabulary. Currently NeuroNames contains standard names, synonyms and definitions of some 2,500 neuroanatomical entities. The nomenclature is maintained by the University of Washington and is the core component of a tool called "BrainInfo". BrainInfo helps one identify structures in the brain. One can either search by a structure name or locate the structure in a brain atlas and get information such as its location in the classical brain hierarchy, images of the structure, what cells it has, its connections and genes expressed there. Information can be accessed by any of some 16,000 synonyms in eight languages. NeuroNames is a source vocabulary of the Metathesaurus of the Unified Medical Language System. == Further reading == ==


id: nomina-anatomica-20260505-0
file: data/en.wikipedia.org/wiki/Nomina_Anatomica-0.md
category: reference
title: Nomina Anatomica
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nomina_Anatomica
date_saved: 2026-05-05T07:13:53.781877+00:00
instance: kb-cron
parent: nomina-anatomica-20260505-0
summary:
Nomina Anatomica (NA) was the international standard on human anatomic terminology from 1895 until it was replaced by Terminologia Anatomica in 1998. In the late nineteenth century some 30,000 terms for various body parts were in use. The same structures were described by different names, depending (among other things) on the anatomist's school and national tradition. Vernacular translations of Latin and Greek, as well as various eponymous terms, were barriers to effective international communication. There was disagreement and confusion among anatomists regarding anatomical terminology. == Editions == The first and last entries in the following table are not NA editions, but they are included for the sake of continuity. Although these early editions were authorized by different bodies, they are sometimes considered part of the same series. Before these codes of terminology, approved at anatomists congresses, the usage of anatomical terms was based on authoritative works of scholars like Galen, Berengario da Carpi, Gaspard Bauhin, Henle, Hyrtl, etc. == The IANC and the FCAT == === Twelfth congress === Around the time of the Twelfth Congress (London, 1985), a dispute arose over the editorial independence of the IANC. The IANC did not believe that their work should be subject to


id: nomina-anatomica-veterinaria-20260505-0
file: data/en.wikipedia.org/wiki/Nomina_Anatomica_Veterinaria-0.md
category: reference
title: Nomina Anatomica Veterinaria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Nomina_Anatomica_Veterinaria
date_saved: 2026-05-05T07:13:54.920675+00:00
instance: kb-cron
parent: nomina-anatomica-veterinaria-20260505-0
summary:
The Nomina Anatomica Veterinaria (often abbreviated as NAV) is a standardized nomenclature. It is made by World Association of Veterinary Anatomists (WAVA). It is used as the standard reference for anatomical (zootomical) terminology in the field of veterinary science regarding domestic mammals (domestic birds are regarded in the Nomina Anatomica Avium). It is based on cats, dogs, pigs, cows, sheep, goats, rabbits and horses—horses being their main subjects. == History == Veterinary anatomists split at the 6th International Congress of the International Anatomical Nomenclature Committee in Paris in 1955, due to disagreements about the Nomina Anatomica. Following Professor Clement Bressou in 1957 in Freiburg (Germany), they formed the International Committee on Veterinary Anatomical Nomenclature, which was renamed World Association of Veterinary Anatomists in 1961, and published the first edition of the Nomina Anatomica Veterinaria (NAV) in 1968. There have been six editions of the NAV, the latest being published in 2017. The fourth edition, published in 1994, was the last commercially printed edition; the fifth and sixth editions are available in PDF. == See also == Nomina Anatomica == References ==


id: permanent-cell-20260505-0
file: data/en.wikipedia.org/wiki/Permanent_cell-0.md
category: reference
title: Permanent cell
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Permanent_cell
date_saved: 2026-05-05T07:13:56.212552+00:00
instance: kb-cron
parent: permanent-cell-20260505-0
summary:
Permanent cells are cells that are incapable of regeneration. These cells are considered to be terminally differentiated and non-proliferative in postnatal life. This includes neurons, heart cells, skeletal muscle cells. Although these cells are considered permanent in that they neither reproduce nor transform into other cells, this does not mean that the body cannot create new versions of these cells. For instance, structures in the bone marrow produce new red blood cells constantly, while skeletal muscle damage can be repaired by underlying satellite cells, which fuse to become a new skeletal muscle cell. Disease and virology studies can use permanent cells to maintain cell count and accurately quantify the effects of vaccines. Some embryology studies also use permanent cells to avoid harvesting embryonic cells from pregnant animals; since the cells are permanent, they may be harvested at a later age when an animal is fully developed. == See also == Labile cells, which multiply constantly throughout life Stable cells, which only multiply when receiving external stimulus to do so == References ==


id: anatomical-plane-20260505-0
file: data/en.wikipedia.org/wiki/Anatomical_plane-0.md
category: reference
title: Anatomical plane
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_plane
date_saved: 2026-05-05T07:13:57.524568+00:00
instance: kb-cron
parent: anatomical-plane-20260505-0
summary:
An anatomical plane is an imaginary flat surface (plane) that is used to transect the body, in order to describe the location of structures or the direction of movements. In anatomy, planes are mostly used to divide the body into sections. In human anatomy three principal planes are used: the sagittal plane, coronal plane (frontal plane), and transverse plane. Sometimes the median plane as a specific sagittal plane is included as a fourth plane. In animals with a horizontal spine the coronal plane divides the body into dorsal (towards the backbone) and ventral (towards the belly) parts and is termed the dorsal plane. A parasagittal plane is any plane that divides the body into left and right sections. The median plane or midsagittal plane is a specific sagittal plane; it passes through the middle of the body, dividing it into left and right halves. The coronal plane, also frontal plane divides the body into front and back parts. The transverse plane, also called the axial or horizontal plane, is perpendicular to the other two planes, and is parallel to the ground. == Terminology == There could be any number of sagittal planes, sometimes called parasagittal planes but they all run


id: anatomical-plane-20260505-1
file: data/en.wikipedia.org/wiki/Anatomical_plane-1.md
category: reference
title: Anatomical plane
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Anatomical_plane
date_saved: 2026-05-05T07:13:57.524568+00:00
instance: kb-cron
parent: anatomical-plane-20260505-0
summary:
In discussing the neuroanatomy of animals, particularly rodents used in neuroscience research, a simplistic convention has been to name the sections of the brain according to the homologous human sections. Hence, what is technically a transverse (orthogonal) section with respect to the body length axis of a rat (dividing anterior from posterior) may often be referred to in rat neuroanatomical coordinates as a coronal section, and likewise a coronal section with respect to the body (i.e. dividing ventral from dorsal) in a rat brain is referred to as transverse. This preserves the comparison with the human brain, whose length axis in rough approximation is rotated with respect to the body axis by 90 degrees in the ventral direction. It implies that the planes of the brain are not necessarily the same as those of the body. However, the situation is more complex, since comparative embryology shows that the length axis of the neural tube (the primordium of the brain) has three internal bending points, namely two ventral bendings at the cervical and cephalic flexures (cervical flexure roughly between the medulla oblongata and the spinal cord, and cephalic flexure between the diencephalon and the midbrain), and a dorsal (pontine or rhombic


id: pugmark-20260505-0
file: data/en.wikipedia.org/wiki/Pugmark-0.md
category: reference
title: Pugmark
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pugmark
date_saved: 2026-05-05T07:13:58.742342+00:00
instance: kb-cron
parent: pugmark-20260505-0
summary:
A pugmark is a footprint left by a wild animal. The distinctive pugmark of an individual species is useful for identification. "Pug" means foot in Hindi (Sanskrit पद् "pad"; Greek πούς "poús"). Pugmark tracking is a technique used by wildlife conservationists to identify the distribution of species. For some species, such as tigers, pugmark tracking is now considered to be an unreliable method of determining an area's total animal population, leading to the rise in the use of alternative techniques to count populations, such as photographic capture. == Field data collection == Indian forester Saroj Raj Choudhury developed the technique of the ‘pugmark census’ in 1966 to track tigers. It involves collecting pugmark tracings and plaster casts from the field and analyzing these to determine the number, track dimensions and spatial distribution of key species. === Technique === In order to obtain good pug impressions, PIPs (pug impression pads) are laid along roads, animal tracks and footpaths. Field data for each pugmark are then collected in specially devised census forms. The plaster casts and tracings along with field information are together analysed with map of the area to remove repetitions and overlaps in pug-evidences collected for the same tiger. The


id: snomed-ct-20260505-0
file: data/en.wikipedia.org/wiki/SNOMED_CT-0.md
category: reference
title: SNOMED CT
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SNOMED_CT
date_saved: 2026-05-05T07:13:59.990399+00:00
instance: kb-cron
parent: snomed-ct-20260505-0
summary:
SNOMED CT or SNOMED Clinical Terms is a systematically organized computer-processable collection of medical terms providing codes, terms, synonyms and definitions used in clinical documentation and reporting. SNOMED CT is considered to be the most comprehensive, multilingual clinical healthcare terminology in the world. The primary purpose of SNOMED CT is to encode the meanings that are used in health information and to support the effective clinical recording of data with the aim of improving patient care. SNOMED CT provides the core general terminology for electronic health records. SNOMED CT comprehensive coverage includes: clinical findings, symptoms, diagnoses, procedures, body structures, organisms and other etiologies, substances, pharmaceuticals, devices and specimens. SNOMED CT is maintained and distributed by SNOMED International, an international non-profit standards development organization, located in London, UK. SNOMED International is the trading name of the International Health Terminology Standards Development Organisation (IHTSDO), established in 2007. SNOMED CT provides for consistent information interchange and is fundamental to an interoperable electronic health record. It provides a consistent means to index, store, retrieve, and aggregate clinical data across specialties and sites of care. It also helps in organizing the content of electronic health records systems by reducing the variability in the way data


id: snomed-ct-20260505-1
file: data/en.wikipedia.org/wiki/SNOMED_CT-1.md
category: reference
title: SNOMED CT
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SNOMED_CT
date_saved: 2026-05-05T07:13:59.990399+00:00
instance: kb-cron
parent: snomed-ct-20260505-0
summary:
Concept Codes – numerical codes that identify clinical terms, primitive or defined, organized in hierarchies Descriptions – textual descriptions of Concept Codes Relationships – relationships between Concept Codes that have a related meaning Reference Sets – used to group Concepts or Descriptions into sets, including reference sets and cross-maps to other classifications and standards. SNOMED CT "Concepts" are representational units that categorize all the things that characterize healthcare processes and need to be recorded therein. In 2011, SNOMED CT included more than 311,000 concepts, which are uniquely identified by a concept ID, e.g. the concept 22298006 refers to Myocardial infarction. All SNOMED CT concepts are organized into acyclic taxonomic (is-a) hierarchies; for example, Viral pneumonia IS-A Infectious pneumonia IS-A Pneumonia IS-A Lung disease. Concepts may have multiple parents, for example Infectious pneumonia is also a child of Infectious disease. The taxonomic structure allows data to be recorded and later accessed at different levels of aggregation. SNOMED CT concepts are linked by approximately 1,360,000 links, called relationships. Concepts are further described by various clinical terms or phrases, called Descriptions, which are divided into Fully Specified Names (FSNs), Preferred Terms (PTs), and Synonyms. Each Concept has exactly one FSN, which is unique


id: snomed-ct-20260505-2
file: data/en.wikipedia.org/wiki/SNOMED_CT-2.md
category: reference
title: SNOMED CT
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SNOMED_CT
date_saved: 2026-05-05T07:13:59.990399+00:00
instance: kb-cron
parent: snomed-ct-20260505-0
summary:
Such expressions are said to have been 'postcoordinated'. Post-coordination avoids the need to create large numbers of defined Concepts within SNOMED CT. However, many systems only allow for precoordinated representations. Reliable analysis and comparison of post-coordinated expressions is possible using appropriate algorithms machinery to efficiently process the expression taking account of the underlying description logic. Major Electronic Health Record Systems (EHRS) have repeatedly complained to IHTSDO and other standards organizations about the "complexity" of post-coordinated expressions. For example, the postcoordinated expression above can be transformed using a set of standard rules to the following "normal form expression" which enables comparison with similar concepts. 64572001 | disease | : 246075003 | causative agent | = 47448006 | hot water | , 363698007 | finding site | = ( 83738005 | index finger structure | : 272741003 | laterality | = 7771000 | left | ) , { 116676008 | associated morphology | = 80247002 | third degree burn injury | , 363698007 | finding site | = 39937001 | skin structure | } Postcoordination is an important desirable feature of a terminology. Prior 2020, International Classification of Diseases (ICD) did not allow post-coordination and SNOMED CT was the only terminology that


id: snomed-ct-20260505-3
file: data/en.wikipedia.org/wiki/SNOMED_CT-3.md
category: reference
title: SNOMED CT
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SNOMED_CT
date_saved: 2026-05-05T07:13:59.990399+00:00
instance: kb-cron
parent: snomed-ct-20260505-0
summary:
=== Known deficiencies and mitigation strategies === Earlier SNOMED versions had faceted structure ordered by semantic axes, requiring that more complex situations required to be coded by a coordination of different codes. This had two major shortcomings. On the one hand, the necessity of post-coordination was perceived as a user-unfriendly obstacle, which has certainly contributed to the low adoption of early SNOMED versions. On the other hand, uniform coding was difficult to obtain. E.g., Acute appendicitis could be post-coordinated in three different ways with no means to compute semantic equivalences. SNOMED RT had addressed this problem by introducing description logic formula. With the addition of CTV3 many concepts were redefined using formal expressions. However, the fusion with CTV3, as a historically grown terminology with many close-to user descriptions, introduced some problems which still affect SNOMED CT. In addition to a confusing taxonomic web of many hierarchical levels with massive multiple inheritance (e.g. there are 36 taxonomic ancestors for Acute appendicitis), many ambiguous, context-dependent concepts have found their way into SNOMED CT. Pre-coordination was sometimes pushed to extremes, so there are, for example, 350 different concepts for burns found on the head. A further phenomenon which characterizes parts of SNOMED CT


id: snomed-ct-20260505-4
file: data/en.wikipedia.org/wiki/SNOMED_CT-4.md
category: reference
title: SNOMED CT
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SNOMED_CT
date_saved: 2026-05-05T07:13:59.990399+00:00
instance: kb-cron
parent: snomed-ct-20260505-0
summary:
==== SNOMED CT and MedDRA ==== There is overlap between MedDRA and SNOMED CT that is not beneficial for pharmaceutical industry. In 2021, two maps map between SNOMED CT and MedDRA were jointly published by both organizations (from SNOMED CT to MedDRA and from MedDRA to SNOMED CT). == Use == SNOMED CT is used in several different ways, some of which are: It captures clinical information at the level of detail needed for the provision of healthcare Through sharing data, it can reduce the need to repeat health history at each new encounter with a healthcare professional Information can be recorded by different people in different locations and combined into simple information views within the patient record Use of a common terminology decreases the potential for differing interpretation of information Structured Data Capture medical forms and questionnaires based on the FHIR standard Electronic recording in a common way reduces errors and can help to ensure completeness in recording all relevant data Standardised information makes analysis easier, supporting quality, cost effective practice, research and future clinical guideline development A clinical terminology allows a health care provider to identify patients based on specified coded information, and more effectively manage screening, treatment


id: snomed-ct-20260505-5
file: data/en.wikipedia.org/wiki/SNOMED_CT-5.md
category: reference
title: SNOMED CT
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/SNOMED_CT
date_saved: 2026-05-05T07:13:59.990399+00:00
instance: kb-cron
parent: snomed-ct-20260505-0
summary:
== Authoring conventions == A goal for SNOMED CT is consistency. Several mechanisms are employed to ensure this. Machine readable concept model is used to check for compliance with a set of rules. Rules for creating fully specified name for a concept define allowed and not allowed patterns. When defining a concept, a proximal primitive parent rule is used (in stated definition) to employ best description logic derived classification of concepts. Separate conventions govern grouping of relationships. Ability to group related relationships is an important strength of SNOMED CT. Rules in Machine Readable Concept Model (MRCM) specify by domain which relationships are never grouped (e.g., 'Is a' or 'Laterality' attributes) and which relationships are always grouped (e.g., 'Finding site'). For correct subsumption inference, some relationships may be in a group but consist of a single relationship. Another convention for SNOMED CT international edition is to avoid creating intermediate primitive concepts (unless medically necessary and impossible to define with existing concept model). An intermediate primitive (=not defined) concept is a non-defined concept that has children concepts and parent concepts. This convention is related to the use of description logic to facilitate terminology maintenance. Because primitive concepts can not be processed by


id: standard-anatomical-position-20260505-0
file: data/en.wikipedia.org/wiki/Standard_anatomical_position-0.md
category: reference
title: Standard anatomical position
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Standard_anatomical_position
date_saved: 2026-05-05T07:14:01.293917+00:00
instance: kb-cron
parent: standard-anatomical-position-20260505-0
summary:
The standard anatomical position, or standard anatomical model, is the scientifically agreed upon reference position for anatomical location terms. Standard anatomical positions are used to standardise the position of appendages of animals with respect to the main body of the organism. In medical disciplines, all references to a location on or in the body are made based upon the standard anatomical position. A straight position is assumed when describing a proximo-distal axis (towards or away from a point of attachment). This helps avoid confusion in terminology when referring to the same organism in different postures. For example, if the elbow is flexed, the hand remains distal to the shoulder even if it approaches the shoulder. == Human anatomy == In standard anatomical position, the human body is standing erect and at rest. Unlike the situation in other vertebrates, the limbs are placed in positions reminiscent of the supine position imposed on cadavers during autopsy. Therefore, the body has its feet together (or slightly separated), and its arms are rotated outward so that the palms are forward, and the thumbs are pointed away from the body (forearms supine). As well, the arms are usually moved slightly out from the body, so


id: systematized-nomenclature-of-medicine-20260505-0
file: data/en.wikipedia.org/wiki/Systematized_Nomenclature_of_Medicine-0.md
category: reference
title: Systematized Nomenclature of Medicine
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Systematized_Nomenclature_of_Medicine
date_saved: 2026-05-05T07:14:02.542763+00:00
instance: kb-cron
parent: systematized-nomenclature-of-medicine-20260505-0
summary:
The Systematized Nomenclature of Medicine (SNOMED) is a systematic, computer-processable collection of medical terms, in human and veterinary medicine, to provide codes, terms, synonyms and definitions which cover anatomy, diseases, findings, procedures, microorganisms, substances, etc. It allows a consistent way to index, store, retrieve, and aggregate medical data across specialties and sites of care. Although now international, SNOMED was started in the U.S. by the College of American Pathologists (CAP) in 1973 and revised into the 1990s. In 2002 CAP's SNOMED Reference Terminology (SNOMED RT) was merged with, and expanded by, the National Health Service's Clinical Terms Version 3 (previously known as the Read codes) to produce SNOMED CT. Versions of SNOMED released prior to 2001 were based on a multiaxial, hierarchical classification system. As in any such system, a disease may be located in a body organ (anatomy), which results in a code in a topography axis and may lead to morphological alterations represented by a morphology code. In 2002 the first release of SNOMED CT adopted a completely different structure. A sub-type hierarchy, supported by defining relationships based on description logic, replaced the axes described in this article. Versions of SNOMED prior to SNOMED CT are planned to


id: terminologia-anatomica-20260505-0
file: data/en.wikipedia.org/wiki/Terminologia_Anatomica-0.md
category: reference
title: Terminologia Anatomica
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminologia_Anatomica
date_saved: 2026-05-05T07:14:03.788839+00:00
instance: kb-cron
parent: terminologia-anatomica-20260505-0
summary:
Terminologia Anatomica (commonly abbreviated TA) is the international standard for human anatomical terminology. It is developed by the Federative International Programme on Anatomical Terminology (FIPAT) a program of the International Federation of Associations of Anatomists (IFAA). == History == The sixth edition of the previous standard, Nomina Anatomica, was released in 1989. The first edition of Terminologia Anatomica, superseding Nomina Anatomica, was developed by the Federative Committee on Anatomical Terminology (FCAT) and the International Federation of Associations of Anatomists (IFAA) and released in 1998. In April 2011, this edition was published online by the Federative International Programme on Anatomical Terminologies (FIPAT), the successor of FCAT. The first edition contained 7635 Latin items. The second edition was released online by FIPAT in 2019 and approved and adopted by the IFAA General Assembly in 2020. The latest errata is dated August 2021. It contains a total of 7112 numbered terms (1-7113 skipping 2590), with some terms repeated. == Adoption and reception == A 2014 survey of the American Association of Clinical Anatomists found that the TA preferred term had the highest frequency of usage in only 53% of the 25 anatomical terms surveyed, and was highest or second-highest for 92% of terms.


id: terminologia-embryologica-20260505-0
file: data/en.wikipedia.org/wiki/Terminologia_Embryologica-0.md
category: reference
title: Terminologia Embryologica
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminologia_Embryologica
date_saved: 2026-05-05T07:14:05.062406+00:00
instance: kb-cron
parent: terminologia-embryologica-20260505-0
summary:
The Terminologia Embryologica (TE) is a standardized list of words used in the description of human embryologic and fetal structures. It was produced by the Federative International Committee on Anatomical Terminology on behalf of the International Federation of Associations of Anatomists and posted on the Internet since 2010. It has been approved by the General Assembly of the IFAA during the seventeenth International Congress of Anatomy in Cape Town (August 2009). It is analogous to the Terminologia Anatomica (TA), which standardizes terminology for adult human anatomy and which deals primarily with naked-eye adult anatomy. It succeeds the Nomina Embryologica, which was included as a component of the Nomina Anatomica. It was not included in the original version of the TA. == Codes == e1.0: General terms [1] e2.0: Ontogeny [2] e3.0: Embryogeny [3] e4.0: General histology [4] e5.0: Bones; Skeletal system [5] e5.1: Joints; Articular system [6] e5.2: Muscles; Muscular system [7] e5.3: Face [8] e5.4: Alimentary system [9] e5.5: Respiratory system [10] e5.6: Urinary system [11] e5.7: Genital systems [12] e5.8: Coelom and septa [13] e5.9: Mesenchymal mesenteric masses [14] e5.10: Endocrine glands [15] e5.11: Cardiovascular system [16] e5.12: Lymphoid system [17] e5.13: Nervous system [18] e5.14: Central nervous


id: terminologia-histologica-20260505-0
file: data/en.wikipedia.org/wiki/Terminologia_Histologica-0.md
category: reference
title: Terminologia Histologica
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminologia_Histologica
date_saved: 2026-05-05T07:14:06.367463+00:00
instance: kb-cron
parent: terminologia-histologica-20260505-0
summary:
The Terminologia Histologica (TH) is the controlled vocabulary for use in cytology and histology. In April 2011, Terminologia Histologica was published online by the Federative International Programme on Anatomical Terminologies (FIPAT), the successor of FCAT. It was intended to replace Nomina Histologica. The Nomina Histologica was introduced in 1977, with the fourth edition of Nomina Anatomica. It was developed by the Federative International Committee on Anatomical Terminology. == Outline == h1.00: Cytology [1] h2.00: General histology [2] H2.00.01.0.00001: Stem cells [3] H2.00.02.0.00001: Epithelial tissue [4] H2.00.02.0.01001: Epithelial cell H2.00.02.0.02001: Surface epithelium H2.00.02.0.03001: Glandular epithelium H2.00.03.0.00001: Connective and supportive tissues [5] H2.00.03.0.01001: Connective tissue cells H2.00.03.0.02001: Extracellular matrix H2.00.03.0.03001: Fibres of connective tissues H2.00.03.1.00001: Connective tissue proper H2.00.03.1.01001: Ligaments H2.00.03.2.00001: Mucoid connective tissue; Gelatinous connective tissue H2.00.03.3.00001: Reticular tissue H2.00.03.4.00001: Adipose tissue H2.00.03.5.00001: Cartilage tissue H2.00.03.6.00001: Chondroid tissue H2.00.03.7.00001: Bone tissue; Osseous tissue H2.00.04.0.00001: Haemotolymphoid complex [6] H2.00.04.1.00001: Blood cells H2.00.04.1.01001: Erythrocyte; Red blood cell H2.00.04.1.02001: Leucocyte; White blood cell H2.00.04.1.03001: Platelet; Thrombocyte H2.00.04.2.00001: Plasma H2.00.04.3.00001: Blood cell production H2.00.04.4.00001: Postnatal sites of haematopoiesis H2.00.04.4.01001: Lymphoid tissue H2.00.05.0.00001: Muscle tissue [7] H2.00.05.1.00001: Smooth muscle tissue H2.00.05.2.00001: Striated muscle tissue H2.00.06.0.00001: Nerve tissue [8] H2.00.06.1.00001: Neuron H2.00.06.2.00001: Synapse H2.00.06.2.00001: Neuroglia h3.01: Bones


id: terminology-of-transgender-anatomy-20260505-0
file: data/en.wikipedia.org/wiki/Terminology_of_transgender_anatomy-0.md
category: reference
title: Terminology of transgender anatomy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Terminology_of_transgender_anatomy
date_saved: 2026-05-05T07:14:07.626494+00:00
instance: kb-cron
parent: terminology-of-transgender-anatomy-20260505-0
summary:
Transgender people use a variety of terms to refer to their genitals and other sexually dimorphic body parts and bodily functions. While some may use the standard clinical and colloquial terms (e.g. penis, dick; vagina, pussy), others follow neologistic approaches. These replacement words serve as alternatives to existing names that may conflict with a person's gender identity and trigger gender dysphoria. In medical contexts, providers may use traditional clinical terms, may mirror patients' preferred terms, or may use alternate terms such as internal genitals and external gonads. Common approaches include using terms associated with analogous body parts (e.g. penis for a clitoris or vice versa), modifying conventional terms to mark for gender (e.g. girldick or boy cunt), and novel terms that do not relate to existing terminology (e.g. front hole for a vagina). Some words are humorous, like hen for a transfeminine penis (contrast cock) or chesticles for a transmasculine breast. The naming of body parts is an important component of transgender sexuality. Trans people may pick different words for different contexts. In both colloquial and medical contexts, experts emphasize deferring to individual preference. == Context == Prior to the 2010s, there was little research on the social aspects of


id: trochlea-20260505-0
file: data/en.wikipedia.org/wiki/Trochlea-0.md
category: reference
title: Trochlea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Trochlea
date_saved: 2026-05-05T07:14:08.822532+00:00
instance: kb-cron
parent: trochlea-20260505-0
summary:
Trochlea (Latin for pulley) is a term in anatomy. It refers to a grooved structure reminiscent of a pulley's wheel. == Related to joints == Most commonly, trochleae bear the articular surface of saddle and other joints: Trochlea of humerus (part of the elbow hinge joint with the ulna) Trochlea of femur (forming the knee hinge joint with the patella) The trochlea tali in the superior surface of the body of talus (part of the ankle hinge joint with the tibia) Trochlear process of the calcaneus In quadrupeds, the trochlea of the radial bone The "knuckles" of the tarsometatarsus which articulate with the proximal phalanges in a bird's foot == Related to muscles == It also can refer to structures which serve as a guide for muscles: Trochlea of superior oblique (see also superior oblique muscle), a mover of the eye which is supplied by the trochlear nerve, or fourth cranial nerve == References ==


id: uberon-20260505-0
file: data/en.wikipedia.org/wiki/Uberon-0.md
category: reference
title: Uberon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Uberon
date_saved: 2026-05-05T07:14:10.028085+00:00
instance: kb-cron
parent: uberon-20260505-0
summary:
The Uber-anatomy ontology (Uberon) is a comparative anatomy ontology representing a variety of structures found in animals, such as lungs, muscles, bones, feathers and fins. These structures are connected to other structures via relationships such as part-of and develops-from. One of the uses of this ontology is to integrate data from different biological databases, and other species-specific ontologies such as the Foundational Model of Anatomy. == References == == External links == http://uberon.org


id: wingspan-20260505-0
file: data/en.wikipedia.org/wiki/Wingspan-0.md
category: reference
title: Wingspan
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Wingspan
date_saved: 2026-05-05T07:14:11.270186+00:00
instance: kb-cron
parent: wingspan-20260505-0
summary:
The wingspan (or just span) of a bird or an airplane is the distance from one wingtip to the opposite wingtip. For example, the Boeing 777–200 has a wingspan of 60.93 metres (199 ft 11 in), and a wandering albatross (Diomedea exulans) caught in 1965 had a wingspan of 3.63 metres (11 ft 11 in), the official record for a living bird. The term wingspan, more technically 'extent', is also used for other winged animals such as pterosaurs, bats, insects, etc., and other aircraft such as ornithopters. In humans, the term wingspan also refers to the arm span, which is the distance between the length from the end of an individual's arm (measured at the fingertips) to the individual's fingertips on the other arm when raised parallel to the ground at shoulder height. == Wingspan of aircraft == The wingspan of an aircraft is always measured in a straight line, from wingtip to wingtip, regardless of wing shape or sweep. === Implications for aircraft design and animal evolution === The lift from wings is proportional to their area, so the heavier the animal or aircraft the bigger that area must be. The area is the product of the span times


id: acropolis-20260505-0
file: data/en.wikipedia.org/wiki/Acropolis-0.md
category: reference
title: Acropolis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Acropolis
date_saved: 2026-05-05T07:14:14.203861+00:00
instance: kb-cron
parent: acropolis-20260505-0
summary:
An acropolis was the settlement of an upper part of an ancient Greek city, especially a citadel, and frequently a hill with precipitous sides, mainly chosen for purposes of defense. The term is typically used to refer to the Acropolis of Athens, yet nearly every Greek city had an acropolis of its own. The term derives from the homonymous Greek word "Ακρόπολις", composed from "akron" (ἄκρον), which means "top", and "polis" (πόλις), which means "city". Acropolises were used as religious centers and places of worship, forts, and places in which the royal and high-status resided. Acropolises became the nuclei of large cities of classical ancient times, and served as important centers of a community. Some well-known acropolises have become the centers of tourism in the present day, and they are a rich source of archaeological information of ancient Greece, especially, the Acropolis of Athens. == Origin == The plural of acropolis (ακρόπολη) is acropolises, also commonly as acropoleis and acropoles, and ακροπόλεις in Greek. The term acropolis is also used to describe the central complex of overlapping structures, such as plazas and pyramids, in many Maya cities, including Tikal and Copán. Acropolis is also the term used by archaeologists and


id: acropolis-20260505-1
file: data/en.wikipedia.org/wiki/Acropolis-1.md
category: reference
title: Acropolis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Acropolis
date_saved: 2026-05-05T07:14:14.203861+00:00
instance: kb-cron
parent: acropolis-20260505-0
summary:
=== Tourism === Acropolises today have become the epicenters of tourism and attraction sites in many modern-day Greek cities. The Athenian Acropolis, in particular, is the most famous, and has the best vantage point in Athens, Greece. Today, tourists can purchase tickets to visit the Athenian Acropolis, including walking, sightseeing, and bus tours, as well as a classic Greek dinner. === Cultural ties === Because of its classical Hellenistic and Greco-Roman style, the ruins of Mission San Juan Capistrano's Great Stone Church in California, United States has been called an American Acropolis. The civilization developed its religious, educational, and cultural aspects of the acropolis, and is used today as a location that holds events, such as operas. The neighborhood of Morningside Heights in New York City is commonly referred to as the "Academic Acropolis" due to its high elevation and the concentration of educational institutions in the area, including Columbia University and its affiliates, Barnard College, Teachers College, Union Theological Seminary and the Jewish Theological Seminary of America; Manhattan School of Music; Bank Street College of Education; and New York Theological Seminary. The analogy is also aided by the neoclassical architecture of the Columbia University campus, which was designed by


id: agora-20260505-0
file: data/en.wikipedia.org/wiki/Agora-0.md
category: reference
title: Agora
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Agora
date_saved: 2026-05-05T07:14:15.374935+00:00
instance: kb-cron
parent: agora-20260505-0
summary:
The agora (English: or ; Ancient Greek: ἀγορά, romanized: agorá, meaning "market" in Modern Greek) was a central public space in ancient Greek city-states. The literal meaning of the word "agora" is "gathering place" or "assembly". The agora was the centre of the athletic, artistic, business, social, spiritual, and political life in the city. The Ancient Agora of Athens is the best example. == Origins == Early in Greek history (10th–4th centuries BC), free-born citizens would gather in the agora for military duty or to hear statements of the ruling king or council. Later, the agora also served as a marketplace, where merchants kept stalls or shops to sell their goods amid arcades. This attracted artisans who built workshops nearby. From these twin functions of the agora as a political and a commercial spot came the two Greek verbs ἀγοράζω, agorázō, "I shop", and ἀγορεύω, agoreúō, "I speak in public". == Ancient Agora of Athens == The Ancient Agora of Athens was situated beneath the northern slope of the Acropolis. The Ancient Agora was the primary meeting ground for Athenians, where members of democracy congregated affairs of the state, where business was conducted, a place to hang out, and watch


id: amphora-20260505-0
file: data/en.wikipedia.org/wiki/Amphora-0.md
category: reference
title: Amphora
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Amphora
date_saved: 2026-05-05T07:14:16.557361+00:00
instance: kb-cron
parent: amphora-20260505-0
summary:
An amphora (; Ancient Greek: ἀμφορεύς, romanized: amphoreús; English pl. amphorae or amphoras) is a type of container with a pointed bottom and characteristic shape and size which fit tightly (and therefore safely) against each other in storage rooms and packages, tied together with rope and delivered by land or sea. The size and shape have been determined from at least as early as the Neolithic Period. Amphorae were used in vast numbers for the transport and storage of various products, both liquid and dry, but mostly for wine. They are most often ceramic, but examples in metals and other materials have been found. Versions of the amphorae were one of many shapes used in Ancient Greek vase painting. The amphora complements a vase, the pithos, which makes available capacities between one-half and two and one-half tons. In contrast, the amphora holds under a half-ton, typically less than 50 kilograms (110 lb). The bodies of the two types have similar shapes. Where the pithos may have multiple small loops or lugs for fastening a rope harness, the amphora has two expansive handles joining the shoulder of the body and a long neck. The necks of pithoi are wide for scooping


id: amphora-20260505-1
file: data/en.wikipedia.org/wiki/Amphora-1.md
category: reference
title: Amphora
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Amphora
date_saved: 2026-05-05T07:14:16.557361+00:00
instance: kb-cron
parent: amphora-20260505-0
summary:
== Production == Roman amphorae were wheel-thrown terracotta containers. During the production process the body was made first and then left to dry partially. Then coils of clay were added to form the neck, the rim, and the handles. Once the amphora was complete, the maker then treated the interior with resin that would prevent permeation of stored liquids. The reconstruction of these stages of production is based primarily on the study of modern amphora production in some areas of the eastern Mediterranean. Amphorae often were marked with a variety of stamps, sgraffito, and inscriptions. They provided information on the production, content, and subsequent marketing. A stamp usually was applied to the amphora at a partially dry stage. It indicates the name of the figlina (workshop) and/or the name of the owner of the workshop. Painted stamps, tituli picti, recorded the weight of the container and the contents, and were applied after the amphora was filled. Today, stamps are used to allow historians to track the flow of trade goods and recreate ancient trade networks. == Classification == The first systematic classification of Roman amphorae types was undertaken by the German scholar Heinrich Dressel. Following the exceptional amphora deposit uncovered


id: amphora-20260505-2
file: data/en.wikipedia.org/wiki/Amphora-2.md
category: reference
title: Amphora
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Amphora
date_saved: 2026-05-05T07:14:16.557361+00:00
instance: kb-cron
parent: amphora-20260505-0
summary:
===== Panathenaic prize amphora ===== Another special type is the Panathenaic prize amphora, with black-figure decoration, produced exclusively as prize vessels for the Panathenaia and retaining the black-figure technique for centuries after the introduction of red-figure vase painting. Some examples bear the inscription "ΤΩΝ ΑΘΗΝΗΘΕΝ ΑΘΛΩΝ" meaning "[I am one] of the prizes from [the goddess] Athena". They contained the prize of oil from the sacred olive tree of the goddess Athena for the winners of the athletic contests held to honour the goddess, and were evidently kept thereafter, and perhaps used to store wine, before being buried with the prize-winner. They depicted goddess Athena on one side (as seen on the second image on this page) and the athletic event on the other side, e.g. a scene of wrestling or running contest etc. === Ancient Rome === By the Roman period utilitarian amphorae were normally the only type produced. The first type of Roman amphora, Dressel 1, appears in central Italy in the late 2nd century BC. This type had thick walls and a characteristic red fabric. It was very heavy, although also strong. Around the middle of the 1st century BC the so-called Dressel 2-4 starts to become


id: artifact-archaeology-20260505-0
file: data/en.wikipedia.org/wiki/Artifact_(archaeology)-0.md
category: reference
title: Artifact (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Artifact_(archaeology)
date_saved: 2026-05-05T07:14:18.953802+00:00
instance: kb-cron
parent: artifact-archaeology-20260505-0
summary:
An artifact or artefact (British English) is a general term for an item made or given shape by humans, such as a tool or a work of art, especially an object of archaeological interest. In archaeology, the word has become a term of particular nuance; it is defined as an object recovered by archaeological endeavor, including cultural artifacts (of cultural interest). "Artefact" is the general term used in archaeology, while in museums the equivalent general term is normally "object", and in art history perhaps artwork or a more specific term such as "carving". The same item may be called all or any of these in different contexts, and more specific terms will be used when talking about individual objects, or groups of similar ones. Artefacts exist in many different forms and can sometimes be confused with ecofacts and features; all three of these can sometimes be found together at archaeological sites. They can also exist in different types of context depending on the processes that have acted on them over time. A wide variety of analyses take place to analyze artefacts and provide information on them. However, the process of analyzing artefacts through scientific archaeology can be hindered by the


id: artifact-archaeology-20260505-1
file: data/en.wikipedia.org/wiki/Artifact_(archaeology)-1.md
category: reference
title: Artifact (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Artifact_(archaeology)
date_saved: 2026-05-05T07:14:18.953802+00:00
instance: kb-cron
parent: artifact-archaeology-20260505-0
summary:
== Analysis == Artifact analysis is determined by what type of artifact is being examined, the best. Lithic analysis refers to analyzing artifacts that are created with stones and are often in the form of tools. Stone artifacts occur often throughout prehistoric times and are, therefore, a crucial aspect in answering archaeological questions about the past. On the surface, lithic artifacts can help archaeologists study how technology has developed throughout history by showing a variety of tools and manufacturing techniques from different periods of time. However, even deeper questions can be answered through this type of analysis; these questions can revolve around topics that include how societies were organized and structured in terms of socialization and the distribution of goods. The following lab techniques all contribute to the process of lithic analysis: petrographic analysis, neutron activation, x-ray fluorescence, particle-induced x-ray emission, individual flake analysis and mass analysis. Another type of artifact analysis is ceramic analysis, which is based around the archaeological study of pottery. This type of analysis can help archaeologists gain information on the raw materials that were used and how they were utilized in the creation of pottery. Laboratory techniques that allow for this are mainly based around


id: biofact-archaeology-20260505-0
file: data/en.wikipedia.org/wiki/Biofact_(archaeology)-0.md
category: reference
title: Biofact (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biofact_(archaeology)
date_saved: 2026-05-05T07:14:20.214138+00:00
instance: kb-cron
parent: biofact-archaeology-20260505-0
summary:
In archaeology, a biofact (or ecofact) is any organic material including flora or fauna material found at an archaeological site that has not been technologically altered by humans yet still has cultural relevance. Biofacts can include but are not limited to plants, seeds, pollen, animal bones, insects, fish bones and mollusks. The study of biofacts, alongside other archaeological remains such as artifacts are a key element to understanding how past societies interacted with their surrounding environment and with each other. Biofacts also play a role in helping archaeologists understand questions of subsistence and reveals information about the domestication of certain plant species and animals which demonstrates, for example, the transition from a hunter-gatherer society to a farming society. Biofacts are differentiated from artifacts in that artifacts are typically considered anything purposefully manipulated or made by human art and workmanship, whereas ecofacts represent matter that has not been made or deliberately influenced by humans yet still has cultural relevance. Biofacts reveal how people respond to their surroundings. There are many different ways that biofacts can be preserved, including through carbonisation, waterlogging, desiccation and mineralization. There are also varying methods of recovering them depending on the location in which they were found.


id: biofact-archaeology-20260505-1
file: data/en.wikipedia.org/wiki/Biofact_(archaeology)-1.md
category: reference
title: Biofact (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biofact_(archaeology)
date_saved: 2026-05-05T07:14:20.214138+00:00
instance: kb-cron
parent: biofact-archaeology-20260505-0
summary:
=== Waterlogging === Waterlogging is another form of preservation that occurs when an ecofact or similar archaeological deposit is preserved under the groundwater table, where a reduction in oxygen allows for preservation. Ecofacts found in most waterlogged archaeology sites are often well preserved yet delicate. To result in a high quality preservation, the groundwater level should remain consistent which ensures anaerobic conditions that ultimately prevent the decay of the organic matter. It is possible that both waterlogged and charred ecofacts can be found at the same archaeological site. === Desiccation === Desiccation is another type of preservation that only occurs in highly arid environments where there is a lack of water, such as a desert. Under these conditions, organic materials gain a resistance to high or low temperatures and UV exposure and retain their key biological structures such as their membranes, nucleic acids and proteins. Where an ecofact experiences this type of preservation, it is possible to rehydrate the tissue of the organism to cause it to resume physiological activity. Whilst rare, desiccation is another form of preservation that allows for the study of ecofacts. === Mineralization === Mineralized ecofacts require a specific set of conditions for correct preservation. Mineralization


id: botija-container-20260505-0
file: data/en.wikipedia.org/wiki/Botija_(container)-0.md
category: reference
title: Botija (container)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Botija_(container)
date_saved: 2026-05-05T07:14:21.533021+00:00
instance: kb-cron
parent: botija-container-20260505-0
summary:
Botija is a term used by archaeologists for a style of ceramic vessel produced in Seville, Spain from early in the 16th-century through the middle of the 19th century. It was radially symmetrical, widest near the top, tapering down to a rounded or nearly pointed bottom. It had a fairly small mouth, and did not have any handles or protusions. While the measurements of individual botijas vary, they tend to cluster around roughly standard sizes. They were sealed with cork stoppers. Botijas were widely used for shipping and storing liquids and some solids, and whole or broken botijas are found almost everywhere the Spanish Empire reached, as well as areas that the Spanish never controlled. Changes to certain elements of botijas over time, documented from jars found in shipwrecks of known date, allow whole jars and sherds found in archaeological sites to be roughly dated. == Names == Spanish records refer to botijas peruleras, botijas medias, botijuelas, botijuelas peruleras, and botixuelas. In colonial Guatemala, the terms botija de vino (wine), botija da aceite (oil), and botija de aceitunas (olives) are attested. Larger jars were commonly called botijas perulera or just peruleras, while the smaller ones were often called botijuellas. Perulera


id: botija-container-20260505-1
file: data/en.wikipedia.org/wiki/Botija_(container)-1.md
category: reference
title: Botija (container)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Botija_(container)
date_saved: 2026-05-05T07:14:21.533021+00:00
instance: kb-cron
parent: botija-container-20260505-0
summary:
=== James === In 1988, Stephen James described more than 1,000 intact ceramic jars recoved from two ships, the Conde de Tolosa and Neustra Senora de Guadalupe, which sank in 1724 in Samana Bay on the north coast of Hispaniola after sailing from Cádiz, Spain. He recognized four forms among the intact jars. They were variously unglazed, glazed only on the interior, or glazed on the interior and exterior. Intact jars from the wrecks were measured, including the volume of water held for jars with interior glazing. Interior glazing is believed to indicate the jar was intended to hold liquids that could be readily absorbed by unglazed ceramics. Sherds from broken jars were examined for paste composition, and were found similar enough to suggest that all of the jars were made from the same source of clay. Form I jars from the wrecks are egg-shaped and the largest found in the shipwrecks, ranging from 47 to 52 cm in height, 29.3 to 32.8 cm diameter at the widest part, and 15 to 20.1 liters in volume. They correspond to Goggin's Middle Style Shape A. Most of the jars have an empty weight of 8.5 to 9.5 kg. The jars have


id: botija-container-20260505-2
file: data/en.wikipedia.org/wiki/Botija_(container)-2.md
category: reference
title: Botija (container)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Botija_(container)
date_saved: 2026-05-05T07:14:21.533021+00:00
instance: kb-cron
parent: botija-container-20260505-0
summary:
== Production == The production of botijas was concentrated in Andalusia, with Seville being the most important center of ceramic production in the Iberian Peninsula during the Early modern period. The Casa de Contratación de Indias (the institution that controlled trade with the New World) was established in Seville in 1503, where it remained until it was transferred to Cádiz in 1717. The need for ceramic containers to hold merchandise sent to the New World led to development of potters' neighborhoods in Seville and Cádiz. Ceramic containers similar to botijas were produced in Portuguese centers such as Aveiro and in Spanish possessions in the Americas, but did not necessarily match the standards of jars produced in Seville. Colin Martin suggested that there were "official" and "civilian" botijas, with the official jars being Goggin's Form B (globular) in two sizes, while civilian jars varied considerable in shape. The jars were thrown in two parts. The body of the jars from the base up to the widest part was thrown as one part, and the top was thrown as another. The two parts were then joined with a slip while being turned on a wheel. Busto-Zapico surmises that the potter throwing the


id: botija-container-20260505-3
file: data/en.wikipedia.org/wiki/Botija_(container)-3.md
category: reference
title: Botija (container)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Botija_(container)
date_saved: 2026-05-05T07:14:21.533021+00:00
instance: kb-cron
parent: botija-container-20260505-0
summary:
== Uses == Botijas were used to store, conserve, and transport solid and liquid goods. The botija was designed for liquid foods, and was used primarily for shipping wine, olive oil, and vinegar. Botijas were also used for solid items that would fit through the mouth of the jar. The ovoid to elongated top-heavy design of botijas, with pointed or rounded bottoms, is evidence they were not intended for long-term storage of liquids while sitting on the ground. Vessels with flat bottoms and wider mouths, such as tinajas and orzas were more suitable for storing liquids. Orzas were usually made with the same paste as ''botijas, making it difficult to assign many sherds to a particular style of container. Worth suggests that botijas intended for oil were lead-glazed to prevent the oil being absorbed by the walls of the botijas and becoming rancid. Botijas carrying wine were lined with pez (colofonia), a resin which sealed the ceramic from the wine. Pez could be removed and reapplied to the interior of botijas as needed. Spices and herbs could be added to the pez to help disguise the taste of the pez, and the botijas were rinsed with vinegar and water to


id: clausurae-20260505-0
file: data/en.wikipedia.org/wiki/Clausurae-0.md
category: reference
title: Clausurae
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Clausurae
date_saved: 2026-05-05T07:14:22.853525+00:00
instance: kb-cron
parent: clausurae-20260505-0
summary:
Clausurae (sing. clausura) are short, linear cut-off walls—a term modern scholars apply to masonry or earthen barriers erected across valleys, gorges or road corridors in Late Antiquity. == Etymology and definition == The word derives from late-Latin clausura “a closing, barrier,” but philological studies have shown that in military contexts it denoted a discrete obstacle rather than a continuous frontier line. Because contemporary texts used the term variably—sometimes for a gate or fortified town—today’s historians reserve clausurae for short walls, normally a few hundred metres to several kilometres long, that seal natural bottlenecks. == Historical context == An imperial rescript of 443 CE required the magister officiorum to report annually “on the state of the camps and of the clausurae along every frontier,” confirming their recognised role in the late-Roman defence-in-depth system. While earlier scholarship misread clausurae as grand linear ramparts, current consensus treats them instead as tactical choke-points manned by modest detachments and supported by nearby forts or watch-towers. == Construction and typology == Most clausurae were stone walls 1–3 m thick and up to 5 m high, sometimes reinforced with towers and a frontal ditch; lighter barriers of timber and earth are also attested. Their alignments exploit steep


id: cradle-of-civilization-20260505-0
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-0.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
A cradle of civilization is a location and a culture where civilization was developed independently of other civilizations in other locations. A civilization is any complex society characterized by the development of the state, social stratification, urbanization, and symbolic systems of communication beyond signed or spoken languages (namely, writing systems and graphic arts). Scholars generally acknowledge six cradles of civilization: Mesopotamia, Ancient Egypt, Ancient India and Ancient China are believed to be the earliest in Afro-Eurasia, while the Caral–Supe civilization of coastal Peru and the Olmec civilization of Mexico are believed to be the earliest in the Americas. All of the cradles of civilization depended upon agriculture for sustenance (except possibly Caral–Supe which may have depended initially on marine resources). All depended upon farmers producing an agricultural surplus to support the centralized government, political leaders, religious leaders, and public works of the urban centers of the early civilizations. == Rise of civilization == The earliest signs of a process leading to sedentary culture can be seen in the Levant to as early as 12,000 BC, when the Natufian culture became sedentary; it evolved into an agricultural society by 10,000 BC. The importance of water to safeguard an abundant and stable


id: cradle-of-civilization-20260505-1
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-1.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
In Mesopotamia (a region encompassing modern Iraq and bordering regions of Southeast Turkey, Northeast Syria and Northwest Iran), the convergence of the Tigris and Euphrates rivers produced rich fertile soil and a supply of water for irrigation. Neolithic cultures emerged in the region from 8000 BC onwards. The civilizations that emerged around these rivers are the earliest known non-nomadic agrarian societies. It is because of this that the Fertile Crescent region, and Mesopotamia in particular, are often referred to as the cradle of civilization. The period known as the Ubaid period (c. 6500 to 3800 BC) is the earliest known period on the alluvial plain, although it is likely earlier periods exist obscured under the alluvium. It was during the Ubaid period that the movement toward urbanization began. Agriculture and animal husbandry were widely practiced in sedentary communities, particularly in Northern Mesopotamia (later Assyria), and intensive irrigated hydraulic agriculture began to be practiced in the south. Around 6000 BC, Neolithic settlements began to appear all over Egypt. Studies based on morphological, genetic, and archaeological data have attributed these settlements to migrants from the Fertile Crescent in the Near East arriving in Egypt and North Africa during the Egyptian and North


id: cradle-of-civilization-20260505-2
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-2.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
=== Northeastern Africa === The region is intermediate between North Africa and East Africa, and encompasses the Horn of Africa (Djibouti, Eritrea, Ethiopia, and Somalia), as well as Sudan, South Sudan, Libya, and Egypt. The region has a very long history of habitation with fossil finds from the early hominids to modern human and is one of the most culturally and linguistically diverse regions of the world, being the home to many civilizations and located on an important trade route that connects multiple continents. A range of linguistic, biological anthropological, archaeological and genetic data have identified shared affinities between early Egypt and northeastern African populations. Genetic evidence has identified the Horn of Africa as a source of a genetic marker "M35/215" Y-chromosome lineage for a significant population component which moved north from that region into Egypt and the Levant. This genetic distribution paralleled the spread of the Afrasian language family with the movement of people from the Horn of Africa into Egypt and added a new demic component to the existing population of Egypt 17,000 years ago. Mainstream scholars have situated the ethnicity and the origins of predynastic, southern Egypt as a foundational community primarily in northeast Africa which included


id: cradle-of-civilization-20260505-3
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-3.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
The developed Neolithic cultures belonging to the phases Pre-Pottery Neolithic A (10,200 BC) and Pre-Pottery Neolithic B (7600 to 6000 BC) appeared in the Fertile Crescent and from there spread eastwards and westwards. Contemporaneously, a grain-grinding culture using the earliest type of sickle blades had replaced the culture of hunters, fishers, and gathering people using stone tools along the Nile. Geological evidence and computer climate modeling studies also suggest that natural climate changes around 8000 BC began to desiccate the extensive pastoral lands of northern Africa, eventually forming the Sahara. Continued desiccation forced the early ancestors of the Egyptians to settle around the Nile more permanently and to adopt a more sedentary lifestyle. The oldest fully developed neolithic culture in Egypt is Fayum A culture that began around 5500 BC. By about 5500 BC, small tribes living in the Nile valley had developed into a series of inter-related cultures as far south as Sudan, demonstrating firm control of agriculture and animal husbandry, and identifiable by their pottery and personal items, such as combs, bracelets, and beads. The largest of these early cultures in northern Upper Egypt was the Badari, which probably originated in the Western Desert; it was known for


id: cradle-of-civilization-20260505-4
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-4.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
The earliest reliably-dated Neolithic site in South Asia is Mehrgarh in the Kacchi Plain of present-day Pakistan dating from 7000 BC. The aceramic Neolithic at Mehrgarh in present-day Pakistan lasts from 7000 to 5500 BC, with the ceramic Neolithic at Mehrgarh lasting up to 3300 BC; blending into the Early Bronze Age. Mehrgarh is one of the earliest sites with evidence of farming and herding in the Indian subcontinent. It is likely that the culture centered around Mehrgarh migrated into the Indus Valley in present-day Pakistan and became the Indus Valley Civilisation. The earliest fortified town in the region is found at Rehman Dheri, dated 4000 BC in Khyber Pakhtunkhwa close to River Zhob Valley in present-day Pakistan. Other fortified towns found to date are at Amri (3600–3300 BC), Kot Diji in Sindh, and at Kalibangan (3000 BC) at the Hakra River. The Indus Valley Civilization starts around 3300 BC with what is referred to as the Early Harappan Phase (3300 to 2600 BC), although at the start this was still a village-based culture, leaving mostly pottery for archaeologists. The earliest examples of the Indus script date to this period, as well as the emergence of citadels representing centralised authority


id: cradle-of-civilization-20260505-5
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-5.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
Drawing on archaeology, geology and anthropology, modern scholars do not see the origins of the Chinese civilization or history as a linear story but rather the history of the interactions of different and distinct cultures and ethnic groups that influenced each other's development. The specific cultural regions that developed Chinese civilization were the Yellow River civilization, the Yangtze civilization, and Liao civilization. Early evidence for Chinese millet agriculture is dated to around 7000 BC, with the earliest evidence of cultivated rice found at Chengtoushan near the Yangtze River, dated to 6500 BC. Chengtoushan may also be the site of the first walled city in China. By the beginning of the Neolithic Revolution, the Yellow River valley began to establish itself as a center of the Peiligang culture, which flourished from 7000 to 5000 BC, with evidence of agriculture, constructed buildings, pottery, and burial of the dead. With agriculture came increased population, the ability to store and redistribute crops, and the potential to support specialist craftsmen and administrators. Its most prominent site is Jiahu. Some scholars have suggested that the Jiahu symbols (6600 BC) are the earliest form of proto-writing in China. However, it is likely that they should not be


id: cradle-of-civilization-20260505-6
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-6.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
=== Ancient Peru === The earliest evidence of agriculture in the Andean region dates to around 9000 BC in Ecuador at sites of the Las Vegas culture. The bottle gourd may have been the first plant cultivated. The oldest evidence of canal irrigation in South America dates to 4700 to 2500 BC in the Zaña Valley of northern Peru. The earliest urban settlements of the Andes, as well as North and South America, are dated to 3500 BC at Huaricanga, in the Fortaleza area, and Sechin Bajo near the Sechin River. Both sites are in Peru. The Caral–Supe or Norte Chico civilization is understood to have emerged around 3200 BC, as it is at that point that large-scale human settlement and communal construction across multiple sites becomes clearly apparent. In the early 21st century, Peruvian archaeologist Ruth Shady established Caral–Supe as the oldest known civilization in the Americas. The civilization flourished near the Pacific coast in the valleys of three small rivers, the Fortaleza, the Pativilca, and the Supe. These river valleys each have large clusters of sites. Further south, there are several associated sites along the Huaura River. Notable settlements include the cities of Caral, the largest and most


id: cradle-of-civilization-20260505-7
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-7.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
=== Mesoamerica === Maize is believed to have been first domesticated in southern Mexico about 7000 BC. The Coxcatlan Caves in the Valley of Tehuacán provide evidence for agriculture in components dated between 5000 and 3400 BC. Similarly, sites such as Sipacate in Guatemala provide maize pollen samples dating to 3500 BC. Around 1900 BC, the Mokaya domesticated one of the dozen species of cacao. A Mokaya archaeological site provides evidence of cacao beverages dating to this time. The Mokaya are also thought to have been among the first cultures in Mesoamerica to develop a hierarchical society. What would become the Olmec civilization had its roots in early farming cultures of Tabasco, which began around 5100 to 4600 BC. The emergence of the Olmec civilization has traditionally been dated to around 1600 to 1500 BC. Olmec features first emerged in the city of San Lorenzo Tenochtitlán, fully coalescing around 1400 BC. The rise of civilization was assisted by the local ecology of well-watered alluvial soil, as well as by the transportation network provided by the Coatzacoalcos River basin. This environment encouraged a densely concentrated population, which in turn triggered the rise of an elite class and an associated demand for


id: cradle-of-civilization-20260505-8
file: data/en.wikipedia.org/wiki/Cradle_of_civilization-8.md
category: reference
title: Cradle of civilization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Cradle_of_civilization
date_saved: 2026-05-05T07:14:24.048097+00:00
instance: kb-cron
parent: cradle-of-civilization-20260505-0
summary:
== Cradle of Western civilization == There is academic consensus that Classical Greece was a major culture that provided the foundation of modern Western culture, democracy, art, theatre, philosophy, and science. For this reason, it is known as the cradle of Western Civilization. Along with Greece, Rome has sometimes been described as a birthplace or as the cradle of Western Civilization because of the role the city had in politics, republicanism, law, architecture, warfare and Western Christianity. == Other uses == Because the word civilization can be defined widely, the term "cradle of civilization" has also been used to describe the origin-point of a particular cultural group, or as the basis for a national mysticism or the origin myth of a nation. This is separate from the use of the term in the study of human prehistory and the development of complex, sedentary societies. "Cradle of civilization" has been used in Indian nationalism (In Search of the Cradle of Civilization 1995) and Taiwanese nationalism (Taiwan;— The Cradle of Civilization 2002). The terms also appear in esoteric pseudohistory, such as the Urantia Book, claiming the title for "the second Eden", or the pseudoarchaeology related to Megalithic Britain (Civilization One 2004, Ancient


id: desert-kite-20260505-0
file: data/en.wikipedia.org/wiki/Desert_kite-0.md
category: reference
title: Desert kite
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Desert_kite
date_saved: 2026-05-05T07:14:25.325383+00:00
instance: kb-cron
parent: desert-kite-20260505-0
summary:
Desert kites (Arabic: مصائد صحراوية, romanized: maṣāʾid ṣaḥrāwiyya, lit. 'desert traps') are dry stone wall structures found in Southwest Asia (Middle East, but also North Africa, Central Asia and Arabia), which were first discovered from the air during the 1920s. There are over 6,000 known desert kites, with sizes ranging from less than a hundred metres to several kilometres. They typically have a kite shape formed by two convergent "antennae" that run towards an enclosure, all formed by walls of dry stone less than one metre high, but variations exist. Little is known about their ages, but the few dated examples appear to span the entire Holocene. While the majority view holds that these structures were traps for hunting game animals such as gazelles, which were driven into the kites, a minority view suggests they were used for managing livestock. == Appearance == Desert kites are stone structures with a convergent shape, composed of linear piles of stones. The structures have lengths ranging from less than a hundred metres to several kilometres and heights of less than one metre, even accounting for erosion. There often are gaps in the lines, which were presumably either purposeful (left by the builders) or


id: desert-kite-20260505-1
file: data/en.wikipedia.org/wiki/Desert_kite-1.md
category: reference
title: Desert kite
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Desert_kite
date_saved: 2026-05-05T07:14:25.325383+00:00
instance: kb-cron
parent: desert-kite-20260505-0
summary:
Both archaeological studies and ethnographic accounts from the 19th and 20th century indicate that desert kites in the Middle East and North Africa were used as traps for wild game. A minority viewpoint is that they were used for livestock management. The disagreement stems mainly from a lack of factual evidence to support either hypothesis, from disputes on the interpretation of evidence, and from the extinction of traditions involving desert kites. There is almost no evidence of what happened to animals after they were trapped or which animals were targeted, but ethnographic analyses indicate that kites were used to hunt ungulates like gazelles, which live in groups and form defensive formations when threatened. The usage of traps in catching animals in the steppe is mentioned in the Epic of Gilgamesh. The construction of kites would have required coordinated work from multiple people and are thus indicative of social organization, even if the trapping of animals is a comparatively simple hunting technique. The use of kites in trapping animals is depicted in Israeli, Mongolian and Sinai petroglyphs; these drawings may not always be contemporaneous to the actual usage of the kites. Petroglyphs relating to kites have been found on kites. Studies


id: destruction-layer-20260505-0
file: data/en.wikipedia.org/wiki/Destruction_layer-0.md
category: reference
title: Destruction layer
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Destruction_layer
date_saved: 2026-05-05T07:14:26.527421+00:00
instance: kb-cron
parent: destruction-layer-20260505-0
summary:
A destruction layer is an archaeological stratum showing clear evidence of widespread burning, structural collapse, weapon finds, human remains, or other signs of violent or catastrophic events. Such layers may result from warfare, seismic activity, accidental fires, or other disasters. In archaeological interpretation, destruction horizons provide chronological anchors for cultural sequences and may indicate major historical turning points, such as the fall of cities, regional crises, or the collapse of polities. Finding comparable destruction layers across several sites in a region can signal a broader episode of unrest or transition, as in the case of the Late Bronze Age collapse. The archaeologist Sharon Zuckerman emphasized that destruction contexts should be analyzed together with the occupational phases preceding and following them, as part of a long-term cultural process rather than isolated events. == Examples == The city of Troy shows several destruction layers, notably Troy II (c. 2200 BC) and Troy VIIa (c. 1200 BC), the latter often associated with the end of the Late Bronze Age and possibly reflecting conflict in the region. The volcanic eruption of Thera (Santorini) produced a well-preserved destruction layer at Akrotiri, dated to the late 17th century BC. The Late Bronze Age cities of the


id: disjecta-membra-20260505-0
file: data/en.wikipedia.org/wiki/Disjecta_membra-0.md
category: reference
title: Disjecta membra
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Disjecta_membra
date_saved: 2026-05-05T07:14:27.707953+00:00
instance: kb-cron
parent: disjecta-membra-20260505-0
summary:
Disjecta membra, also written disiecta membra, is Latin for "scattered fragments" (also scattered limbs, members, or remains) and is used to refer to surviving fragments of ancient poetry, manuscripts, and other literary or cultural objects, including even fragments of ancient pottery. It is derived from disiecti membra poetae, a phrase used by Horace, a Roman poet. == Ancient and medieval poetry, literature, and manuscripts == Fragments of ancient writing, especially ancient Latin poetry found in other works, are commonly referred to as disjecta membra. The terms disiecta membra and disjecta membra are paraphrased from the Roman lyric poet Horace (65 BC – 8 BC), who wrote of disiecti membra poetae in his Satires, 1.4.62, referring to the "limbs of a dismembered poet". In full, the term originally appeared as Invenias etiam disiecti membra poetae, in reference to the earlier Roman poet Ennius. Although Horace's intended meaning remains the subject of speculation and debate, the passage is often taken to imply that if a line from poetry were torn apart and rearranged, the dismembered parts of the poet would still be recognisable. In this sense, in the study of literature, disjecta membra is often used to describe the piecing together of


id: disturbance-archaeology-20260505-0
file: data/en.wikipedia.org/wiki/Disturbance_(archaeology)-0.md
category: reference
title: Disturbance (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Disturbance_(archaeology)
date_saved: 2026-05-05T07:14:28.951367+00:00
instance: kb-cron
parent: disturbance-archaeology-20260505-0
summary:
A disturbance is any change to an archaeological site due to events which occurred after the site was laid down. Disturbances may be caused by natural events or human activity, and may result in loss of archaeological value. In some cases, it can be difficult to distinguish between features caused by human activity in the period of interest, and features caused by later human activity or natural processes. == Causes == === Natural causes === The soil scientist Francis D. Hole identified nine natural processes resulting in soil disturbance, including the movements of animals and plants (known as bioturbation, and including burrowing, root growth and treefalls); freezing and thawing; movement under gravity (including earthflow and rockslides); swelling and shrinking of clays; the actions of wind and water; the growth and dissolution of salt crystals; and movement caused by earthquakes. Different sites are subject to different degrees, combinations, and interactions of these processes, and archaeologists working with a given site must be familiar with the processes in play at that site to avoid the risk of misinterpretation. In some environments, animal activity can completely turn over the surface soil in as few as five to six years. The activity of earthworms,


id: ephyraean-style-20260505-0
file: data/en.wikipedia.org/wiki/Ephyraean_style-0.md
category: reference
title: Ephyraean style
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Ephyraean_style
date_saved: 2026-05-05T07:14:30.128916+00:00
instance: kb-cron
parent: ephyraean-style-20260505-0
summary:
The Ephyraean style is a distinctive type of Mycenaean pottery defined by a specific vessel, the Ephyraean goblet. This ware was first identified by archaeologist Carl Blegen during his excavations at Korakou, a site near Corinth. Blegen named the ware after Ephyra (Ancient Corinth), that he thought he was excavating. The style's stratigraphic position places it firmly in the Late Helladic II (LH II) period (approx. 1450–1350 BC), and it is considered a key "date-mark" for this phase of the Mycenaean era. While other shapes, such as jugs, were sometimes decorated in the Ephyraean manner, the goblet is its most characteristic form. == Goblets == === Shape, origin, and fabric === The Ephyraean goblet is a decorated subdivision of Yellow Minyan ware, which itself is a refined development of Middle Helladic Grey Minyan ware. Its characteristic shape—a one- or two-handled goblet with a short stem—is thought to be a direct imitation of metal vessels. This Helladic origin, derived from Minyan goblets, was emphasized by scholars like Persson and Wace, who refuted earlier theories by Arthur Evans that the shape had a Minoan origin. The classic goblet has a specific shape: A short stem with a hollowed foot. A deep bowl


id: favissa-20260505-0
file: data/en.wikipedia.org/wiki/Favissa-0.md
category: reference
title: Favissa
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Favissa
date_saved: 2026-05-05T07:14:31.628120+00:00
instance: kb-cron
parent: favissa-20260505-0
summary:
A favissa is a cultic storage place, usually a pit or an underground cellar, for sacred utensils and votive objects no longer in use. Favissae were located within the sacred temple precincts of the various ancient Mediterranean civilizations. Archaeologists have found such pits in Ancient Egypt, the Roman world and in the Phoenician and Punic world. == Etymology == The term is derived from the Etruscan or related to the Latin fovea "pit". During the time of ancient Rome, the term favissa referred to a cylindrical underground storage space, specifically designed to house votive objects. These repositories were typically located outside the main sanctuary but within the sacred grounds known as temenos. The Roman favissa served a similar purpose as the Greek treasury, functioning as a dedicated space for storing valuable offerings and dedicatory items. == Roman favissae == Similar to other ancient religions, the Romans had a tradition of offering relatively inexpensive objects made of materials like bronze, lead, tin, or common clay as votive offerings to the temple deities. Over time, the quantity of these votive objects became excessive, necessitating their removal. However, it was crucial for priests to ensure these offerings remained within consecrated ground and were


id: foundation-deposit-20260505-0
file: data/en.wikipedia.org/wiki/Foundation_deposit-0.md
category: reference
title: Foundation deposit
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Foundation_deposit
date_saved: 2026-05-05T07:14:32.813442+00:00
instance: kb-cron
parent: foundation-deposit-20260505-0
summary:
Foundation deposits are the archaeological remains of the ritual burial of materials under the foundations of buildings. == Ancient Egypt == In the case of Ancient Egypt, foundation deposits took the form of ritual mudbrick lined pits or holes dug at specific points under temples or tombs, which were filled with ceremonial objects, usually amulets, scarabs, food, or ritual miniature tools, and were supposed to prevent the building from falling into ruin. == Examples == == See also == Builders' rites Cornerstone Cyrus Cylinder == References ==


id: glyph-20260505-0
file: data/en.wikipedia.org/wiki/Glyph-0.md
category: reference
title: Glyph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Glyph
date_saved: 2026-05-05T07:14:34.076369+00:00
instance: kb-cron
parent: glyph-20260505-0
summary:
A glyph ( GLIF) is any kind of purposeful mark. In typography, a glyph is "the specific shape, design, or representation of a character". It is a particular graphical representation, in a particular typeface (or computer font), of an element of written language. That "element" is called a grapheme – the conceptual abstraction of some letter, number or symbol, which is independent of the glyph designed to represent it in a particular font. == Glyphs, graphemes and characters == In modern English, each symbol (such as a letter or numerical digit) is a grapheme that can be represented by a single glyph that is unique to the font where it used. Detailed differences in the design of each glyph in the repertoire is the distinguishing feature of a typeface (or computer font) but in each case the grapheme being represented is constant. In most languages written in any variety of the Latin alphabet except English, the use of diacritics to signify a sound mutation is common. For example, the grapheme ⟨à⟩ requires two glyphs: the basic |a| and the grave accent |`|. In general, a diacritic is regarded as a glyph, even if it is contiguous with the rest of


id: haltern-cooking-pot-20260505-0
file: data/en.wikipedia.org/wiki/Haltern_cooking_pot-0.md
category: reference
title: Haltern cooking pot
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haltern_cooking_pot
date_saved: 2026-05-05T07:14:35.343034+00:00
instance: kb-cron
parent: haltern-cooking-pot-20260505-0
summary:
The Haltern cooking pot is an earthenware vessel from the Roman period. Due to its frequent occurrence as utility pottery in eastern Gallic and Rhinelandic settlements and military sites of the 1st century AD, it serves as a type fossil in provincial Roman archaeology for dating archaeological finds. In ceramic typology, the form is referred to as Haltern 91 after its eponymous site, the Haltern Roman camp. == Form == The Haltern cooking pot is a bulbous vessel whose widest diameter is at the shoulder. It is characterized by an inwardly curved, grooved rim with a sharp shoulder angle. It tapers steeply toward the base, with the narrowest part located at the flat base. Early vessels were handmade, but during the Tiberian era, they were replaced by wheel-thrown pots, maintaining the same shape. The vessel surface is often coated with a clay slip, roughened with straw or twigs before firing to improve grip. The sherd is clay-based with sand tempering. Depending on the production site, it is black, light-colored, or reddish. Two variants are distinguished in current literature. Haltern 91 A consists of poorly levigated clay, with reddish-brown to black sherds and a cork-like texture ("cork ware"). In contrast, Haltern


id: holocene-calendar-20260505-0
file: data/en.wikipedia.org/wiki/Holocene_calendar-0.md
category: reference
title: Holocene calendar
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Holocene_calendar
date_saved: 2026-05-05T07:14:36.505459+00:00
instance: kb-cron
parent: holocene-calendar-20260505-0
summary:
The Holocene calendar, also known as the Holocene Era or Human Era (HE), is a year numbering system that adds exactly 10,000 years to the currently dominant (AD/BC or CE/BCE) numbering scheme, placing its first year near the beginning of the Holocene geological epoch and the Neolithic Revolution, when humans shifted from a hunter-gatherer lifestyle to agriculture and fixed settlements. The current year by the Gregorian calendar, AD 2026, is 12026 HE in the Holocene calendar. The HE scheme was first proposed by Cesare Emiliani in 1993 (11993 HE), though similar proposals to start a new calendar at the same date had been put forward decades earlier. Emiliani thereby dismissed his original proposal to align the era with the 7980-year Julian cycles, i.e. start with the epoch in 4713 BCE (5288 HE). == Overview == Cesare Emiliani's proposal for a calendar reform sought to solve a number of alleged problems with the current Anno Domini era, also called the Common Era, which numbers the years of the commonly accepted world calendar. These issues include: The Anno Domini era has no year "zero", with 1 BC followed immediately by AD 1, making calculation of time spans difficult. The years BC/BCE are


id: olive-jar-20260505-0
file: data/en.wikipedia.org/wiki/Olive_jar-0.md
category: reference
title: Olive jar
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Olive_jar
date_saved: 2026-05-05T07:14:37.702321+00:00
instance: kb-cron
parent: olive-jar-20260505-0
summary:
Spanish olive jars are ceramic containers produced in the 15th through the 19th centuries and used for transporting various products to Spanish colonies. Olive jars are commonly found in archaeological sites throughout the former Spanish Empire, including shipwrecks, and have also been found at sites that were never under Spanish control. Variations in the form of individual olive jars have been used by archaeologists to date sites in which olive jars and sherds have been found. == Names == The term "Spanish Olive Jar" was introduced by William Henry Holmes in 1903, as he believed a specific type of sherd found in archaeological sites in America came from jars that had been used to ship olives to America. American archaeologists have since then often called Spanish-produced ceramic containers found at archaeological sites "olive jars" or "Spanish olive jars". They have been inconsistent in their use of "olive jar", varying between "olive jar" as a name for all Spanish ceramics, and as a name for the most common type, the botija, which has a distinctive form and paste. Other types of Spanish ceramics that are sometimes called "olive jars", and sometimes "Spanish storage jars" include the cantimplora, tinaja, and orza. American


id: olive-jar-20260505-1
file: data/en.wikipedia.org/wiki/Olive_jar-1.md
category: reference
title: Olive jar
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Olive_jar
date_saved: 2026-05-05T07:14:37.702321+00:00
instance: kb-cron
parent: olive-jar-20260505-0
summary:
== Archaeological finds == Olive jars found on shipwrecks of known date help establish a time line for changes in styles. Botijas were important shipping containers in the Spanish Empire, but were also used in wider trade networks. They have been found in the British Isles, Brittany, the Netherlands, Poland, Sweden, Caribbean Islands, Mexico, Colombia, Ecuador, Argentina, Canada, the Philippines, Australia, the Solomon Islands, English settlements in North and South Carolina, and at the site of a Native American camp in Nebraska. Olive jars probably were used extensively by the Spanish for travel by land or small water vessels, carrying wine, olive oil, and water. The presence of olive jar sherds at archaeological sites are a good indicator of Spanish presence that lasted long enough for one or more jars to break. On the other hand, the absence of such sherds at archaeological sites that do have other artifacts of Spanish provenance, which may have arrived through trade or as plunder, may indicate that there was no Spanish presence at the site. == References == == Sources == Beaman, Thomas E., Jr.; Mintz, John J. (Summer 1998). "Iberian Olive Jars at Brunswick Town and Other British Colonial Sites: Three Models


id: palace-style-20260505-0
file: data/en.wikipedia.org/wiki/Palace_Style-0.md
category: reference
title: Palace Style
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Palace_Style
date_saved: 2026-05-05T07:14:39.082684+00:00
instance: kb-cron
parent: palace-style-20260505-0
summary:
The Palace Style is an archaeological term, coined by Sir Arthur Evans, for a style of Minoan pottery. It flourished during the Late Minoan II (LMII) period, from approximately 1450 to 1400 BC. This "magnificent" style disappears after the final destruction of the Knossos palace around 1400 BC. The style is characterized by a "grandiose and increasingly formal character" as well as "geometric severity" and "rhythmic, balanced" designs. It is often described as "grand, formal, tectonic, and rather cold" compared to the "fresher" Minoan styles that preceded it, such as the Floral Style and Marine Style. It represents a shift toward more schematic, symmetrical, and "stiff" designs, losing the "vibrancy" of earlier naturalistic art. == Etymology == The term "Palace Style" was chosen because the pottery, primarily large, high-quality storage vessels, was found almost exclusively in the vicinity of the Palace of Knossos. == Characteristics and evolution == The Palace Style is a monumental style that adapts earlier naturalistic motifs into more stylized designs. Motifs are often inspired by decorations found on the palace walls, and many designs reproduce details from metalwork models. Common motifs include: Stylized plants, especially the papyrus (often seen with wave patterns), lilies, and reeds. Marine


id: porticus-20260505-0
file: data/en.wikipedia.org/wiki/Porticus-0.md
category: reference
title: Porticus
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Porticus
date_saved: 2026-05-05T07:14:40.237009+00:00
instance: kb-cron
parent: porticus-20260505-0
summary:
In church architecture, a porticus (Latin for "portico") is usually a small room in a church. Commonly, porticuses form extensions to the north and south sides of a church, giving the building a cruciform plan. They may function as chapels, rudimentary transepts or burial-places. For example, Anglo-Saxon kings of Kent were buried in the south porticus at St Augustine's Abbey in Canterbury, with the exception of Eadberht II, who was buried in a similar location in St Mary's Church, Reculver. This feature of church design originated in the late Roman period and continued to appear in those built on the European continent and, in Anglo-Saxon England, until the 8th century. == Notes == == References == === Citations === === Bibliography === Cherry, B. (1981) [1976], "Ecclesiastical architecture", in Wilson, D.M. (ed.), The Archaeology of Anglo-Saxon England, Cambridge University Press, pp. 151–200, ISBN 0-521-28390-6 Kelly, S. (2008), "Reculver Minster and its early charters", in Barrow, J.; Wareham, A. (eds.), Myth, Rulership, Church and Charters Essays in Honour of Nicholas Brooks, Ashgate, pp. 67–82, ISBN 978-0-7546-5120-8


id: proto-city-20260505-0
file: data/en.wikipedia.org/wiki/Proto-city-0.md
category: reference
title: Proto-city
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Proto-city
date_saved: 2026-05-05T07:14:41.432872+00:00
instance: kb-cron
parent: proto-city-20260505-0
summary:
A proto-city is a large, dense Neolithic settlement that is largely distinguished from a city by its lack of planning and centralized rule. The term mega-sites is also used. While the precise classification of many sites considered proto-cities is ambiguous and subject to considerable debate, common examples include sites of the Pre-Pottery Neolithic B culture and following cultures in the Fertile Crescent such as Jericho and Çatalhöyük, sites of the Cucuteni-Trypillia culture in Southeast Europe, and of the Ubaid period in Mesopotamia. These sites pre-date the Mesopotamian city-states of the Uruk period that mark the development of the first indisputable urban settlements, with the emergence of cities such as Uruk at the end of the Fourth Millennium, B.C. The emergence of cities from proto-urban settlements is a non-linear development that demonstrates the varied experiences of early urbanization. Whilst the proto-urban sites of the Ubaid period in northern Mesopotamia anticipate the social and political developments of the first Sumerian cities, many proto-cities show little correlation with later urban settlements. The development of cities and proto-cities and the transition away from hunting and gathering toward agriculture is known as the Neolithic Revolution. == Definition == The label of a proto-city is applied


id: proto-city-20260505-1
file: data/en.wikipedia.org/wiki/Proto-city-1.md
category: reference
title: Proto-city
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Proto-city
date_saved: 2026-05-05T07:14:41.432872+00:00
instance: kb-cron
parent: proto-city-20260505-0
summary:
== Development of cities == The development of cities from proto-urban sites was not a linear progression in most cases. Rather, proto-cities are defined as "early experiments" in high-density living that "did not develop further", particularly in their level of population, suggesting a more flexible and complex trajectory to urbanisation. Alternatively, a number of proto-urban population centres such as Tell Brak in Northern Mesopotamia in the fourth millennium B.C. can be considered "successful experiments" that adopted new social and political institutions to mitigate internal conflicts. These sites anticipate the administrative practices of Southern Mesopotamian city-states such as Uruk, such as the use of seals to denote ownership or control. At Tell Brak, a stamp sealing with a motif of a lion suggests the authority of a senior official; in later periods Mesopotamians considered the lion a symbol of kingship. By the end of the fourth millennium B.C., the emergence of the city of Uruk in Southern Mesopotamia reflected the social, cultural and political developments of proto-cities in the region during prior centuries. The city can be viewed as "the culmination of a series of increasingly successful experiments in settlement nucleation". Extremely large in scale (250 ha, twice the size of


id: qiance-20260505-0
file: data/en.wikipedia.org/wiki/Qiance-0.md
category: reference
title: Qiance
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Qiance
date_saved: 2026-05-05T07:14:43.789970+00:00
instance: kb-cron
parent: qiance-20260505-0
summary:
Qiance, i.e., qiǎncè (Chinese traditional: 遣冊; Chinese simplified: 遣册), is a term for funerary-furnishing inventory list documents excavated from Chinese archaeological sites. == Description == Qiance were usually written on bamboo and wooden slips. According to Professor Qiu Xigui of Fudan University, most of the bamboo and wooden slips unearthed from ancient tombs and frontier fortress sites in China are ancient books and qiance. According to archaeological discoveries and ancient textual evidence, scholars believe that shorter funerary inventory lists, usually with less than one hundred item names, were written on fengfang, a wooden tablet, instead. == Purpose == It has been argued that qiance, together with the other tomb objects, were meant to guarantee the tomb owner's social status in the world beyond. == References ==


id: seriation-archaeology-20260505-0
file: data/en.wikipedia.org/wiki/Seriation_(archaeology)-0.md
category: reference
title: Seriation (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seriation_(archaeology)
date_saved: 2026-05-05T07:14:44.954311+00:00
instance: kb-cron
parent: seriation-archaeology-20260505-0
summary:
In archaeology, seriation is a relative dating method in which assemblages or artifacts from numerous sites in the same culture are placed in chronological order. Where absolute dating methods, such as carbon dating, cannot be applied, archaeologists have to use relative dating methods to date archaeological finds and features. Seriation is a standard method of dating in archaeology. It can be used to date stone tools, pottery fragments, and other artifacts. In Europe, it has been used frequently to reconstruct the chronological sequence of graves in a cemetery (e.g. Jørgensen 1992; Müssemeier, Nieveler et al. 2003). == Contextual and frequency seriation == Two different variants of seriation have been applied: contextual seriation and frequency seriation (Renfrew and Bahn 1996, pp. 116–117). Whereas contextual seriation is based on the presence or absence of a design style, frequency seriation relies on measuring the proportional abundance or frequency of a design style. Contextual seriation is often used for reconstructing the chronological sequence of graves as only the presence or absence of a design style or type is important. Frequency seriation is applied in cases of large quantities of objects belonging to the same style. An example of this being assemblages of pottery shards


id: seriation-archaeology-20260505-1
file: data/en.wikipedia.org/wiki/Seriation_(archaeology)-1.md
category: reference
title: Seriation (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seriation_(archaeology)
date_saved: 2026-05-05T07:14:44.954311+00:00
instance: kb-cron
parent: seriation-archaeology-20260505-0
summary:
=== Correspondence analysis for seriation purposes === Today, the most popular seriation method both for contextual and frequency problems is based on correspondence analysis. The sequence of the first axis of a correspondence analysis is considered the best seriation order (Shennan 1997, p. 342; Lock 2003, p. 127; Jensen & Høilund Nielsen 1997). Using this technique, not only the sequence of the objects but also those of the design styles is established. Note that external evidence is needed to establish the direction of the sequence calculated, i.e. the method does not tell whether the first object in the sequence is the oldest or the youngest object. Kendall (1971) applied multidimensional scaling to the cemetery data of Münsingen. The resulting scatterplot showed the form of a horse-shoe where the graves were arranged on the curve according to their chronological order. Similarly, a mapping of the component scores for the first two axes of the correspondence analysis result will display a parabola if the design styles considered are controlled by one factor only (like chronology). This is called the arch effect by Hill and Gauch (1980). Both Kendall and Jensen & Høilund Nielsen (1997) created artificial data sets to show that the


id: seriation-archaeology-20260505-2
file: data/en.wikipedia.org/wiki/Seriation_(archaeology)-2.md
category: reference
title: Seriation (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Seriation_(archaeology)
date_saved: 2026-05-05T07:14:44.954311+00:00
instance: kb-cron
parent: seriation-archaeology-20260505-0
summary:
=== Example 3: Ideal data, seriation and correspondence analysis === The contingency table shows 29 contexts with ideal seriation data as created by Kendall and Jensen & Høilund Nielsen (see above). With each new context a new type appears and another type disappears. For this regular data, it seems reasonable to assume constant time intervals for contexts adjacent in time. The correspondence analysis results shown in the figures below were calculated on the basis of 49 contexts with ideal seriation data. The scatterplot of the first two correspondence analysis axes shows the typical parabola shape. The display of the scores on the first and the third axes exhibits points lying on a third degree polynomial curve. Similarly, the plot of the scores on the first and the fourth axes will show a fourth degree polynomial for ideal data – and so on. Note that the distances of the scores for adjacent contexts on the first axis vary: At the beginning and the end, the distances are extremely small, the largest distances in the centre is about 30 times as large as the smallest distance. Hill and Gauch (1979) created a similar contingency table with a regular structure with each context


id: technofossil-20260505-0
file: data/en.wikipedia.org/wiki/Technofossil-0.md
category: reference
title: Technofossil
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Technofossil
date_saved: 2026-05-05T07:14:46.134506+00:00
instance: kb-cron
parent: technofossil-20260505-0
summary:
A technofossil refers to geological evidence of human technological activity preserved in Earth's strata that will persist for millions of years. These anthropogenic materials form distinctive markers in the geological record, with many geologists, paleobiologists, and environmental researchers stating that they would provide future evidence of humanity's industrial and consumer-oriented civilization. Technofossils represent a significant aspect of the proposed Anthropocene epoch, characterized by humanity's profound geological impact on the planet due to the mass production of synthetic resources, modified biological remains, and chemical or radioactive markers. == Concept == The term "technofossil", first coined in 2014, describes manufactured or modified materials that possess sufficient durability to persist in Earth's geological record for millions of years. Unlike traditional biological fossils, technofossils result from human technological processes rather than natural and biological processes. These persistent artifacts form a distinctive stratigraphic signature that several geologists and environmental scientists state will remain identifiable to future geologists or intelligent entities examining Earth's history. University of Leicester Department of Geology professors Jan Zalasiewicz, Mark Williams, and Sarah Gabbott, consider technofossils a defining characteristic of the Anthropocene. Each theorize that their durability and vast global distribution are in the process of creating an unprecedented geological signature distinct


id: technofossil-20260505-1
file: data/en.wikipedia.org/wiki/Technofossil-1.md
category: reference
title: Technofossil
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Technofossil
date_saved: 2026-05-05T07:14:46.134506+00:00
instance: kb-cron
parent: technofossil-20260505-0
summary:
== Preservation == Like traditional fossils, technofossils will require specific conditions for long-term preservation. Burial beneath sediment, particularly in marine or lacustrine environments, are believed to provide the most favorable conditions for preservation. Subsiding coastal urban areas provide proper conditions for preservation of human infrastructure, as gradually sinking land allows for sediment accumulation that protects artifacts from erosion and weathering. Landfills create artificial preservation environments that inhibit degradation by limiting oxygen exposure and microbial activity. Deep geological formations provide stable preservation environments for subterranean technofossils, protecting them from surface erosional processes. Many technofossils will release chemicals into the environment over geological timeframes, potentially affecting future ecosystems. === Cultural preservation === Some technofossils may unintentionally preserve cultural information. Paper documents demonstrate fossilization potential based on preserved ancient leaves and plant materials that underwent similar preservation processes. Graphite from pencils shows considerable geological stability, potentially preserving written or drawn information. Children's drawings are posited to represent potentially enduring human cultural expressions due to their simple graphite composition and potential for burial in sediments. Digital information storage media, despite their abundance, may prove less durable than older analog technologies, creating a potential gap in the cultural record preserved for future study. == See


id: virtual-archaeology-20260505-0
file: data/en.wikipedia.org/wiki/Virtual_archaeology-0.md
category: reference
title: Virtual archaeology
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Virtual_archaeology
date_saved: 2026-05-05T07:14:58.279288+00:00
instance: kb-cron
parent: virtual-archaeology-20260505-0
summary:
Virtual archaeology is a subfield of digital archeology that creates and use virtual models and simulations of archaeological sites, artifacts, and processes. It makes use of 3D modeling, virtual reality (VR), augmented reality (AR), and other technologies to recreate or visualize archaeological findings. == Etymology == It is a term introduced in 1990 by archaeologist and computer scientist Paul Reilly to describe the use of computer based simulations of archaeological excavations. Since that time, scientific results related to virtual archaeology were annually discussed, among others, at Computer Applications and Quantitative Methods in Archaeology (CAA). The keyword "visualization" defined the aim of the virtual archaeology in the London Charter Initiative: It should be made clear to users what a computer-based visualization seeks to represent, for example the existing state, an evidence-based restoration or an hypothetical reconstruction of a cultural heritage object or site, and the extent and nature of any factual uncertainty. Since its introduction, the focus of the term has been extended to explore methods that increase the visibility and accessibility of archaeology. Today it serves as an integration paradigm that allows many modern three-dimensional datasets to be analysed together, taking account preliminary reconstructions of archaeological sites and guiding further


id: waterlogging-archaeology-20260505-0
file: data/en.wikipedia.org/wiki/Waterlogging_(archaeology)-0.md
category: reference
title: Waterlogging (archaeology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Waterlogging_(archaeology)
date_saved: 2026-05-05T07:14:59.422773+00:00
instance: kb-cron
parent: waterlogging-archaeology-20260505-0
summary:
In archaeology, waterlogging is the long-term exclusion of air by groundwater, which creates an anaerobic environment that can preserve artifacts perfectly. Such waterlogging preserves perishable artifacts. Thus, in a site which has been waterlogged since the archaeological horizon was deposited, exceptional insight may be obtained by study of artifacts made of leather, wood, textile or similar materials. 75-90% of the archaeological remains at wetland sites are found to be organic material. Tree rings found from logs that have been preserved allow archaeologists to accurately date sites. Wetland sites include all those found in lakes, swamps, marshes, fens, and peat bogs. Peat bogs, nearly all of which occur in northern latitudes, are some of the most important environments for wetland archaeology. Peat bogs have likewise preserved many wooden trackways, including the world's oldest road, which is a 6,000-year-old one-mile stretch of track. Bog bodies are the best-known finds from the peat bogs of northwest Europe, with most of them dating from the Iron Age. Most corpses that were found were individuals that met a violent death and were probably either executed as criminals or killed as a sacrifice before thrown into the bog. For example, the Old Croghan Man was stabbed,


id: acclimatization-20260505-0
file: data/en.wikipedia.org/wiki/Acclimatization-0.md
category: reference
title: Acclimatization
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Acclimatization
date_saved: 2026-05-05T07:15:01.114425+00:00
instance: kb-cron
parent: acclimatization-20260505-0
summary:
Acclimatization or acclimatisation (also called acclimation or acclimatation) is the process in which an individual organism adjusts to a change in its environment (such as a change in altitude, temperature, humidity, photoperiod, or pH), allowing it to maintain fitness across a range of environmental conditions. Acclimatization occurs in a short period of time (hours to weeks), and within the organism's lifetime (compared to adaptation, which is evolution, taking place over many generations). This may be a discrete occurrence (for example, when mountaineers acclimate to high altitude over hours or days) or may instead represent part of a periodic cycle, such as a mammal shedding heavy winter fur in favor of a lighter summer coat. Organisms can adjust their morphological, behavioral, physical, and/or biochemical traits in response to changes in their environment. While the capacity to acclimate to novel environments has been well documented in thousands of species, researchers still know very little about how and why organisms acclimate the way that they do. == Names == The nouns acclimatization and acclimation (and the corresponding verbs acclimatize and acclimate) are widely regarded as synonymous, both in general vocabulary and in medical vocabulary. The synonym acclimation is less commonly encountered, and fewer


id: adaptation-20260505-0
file: data/en.wikipedia.org/wiki/Adaptation-0.md
category: reference
title: Adaptation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Adaptation
date_saved: 2026-05-05T07:15:02.299236+00:00
instance: kb-cron
parent: adaptation-20260505-0
summary:
In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the population during that process. Thirdly, it is a phenotypic trait or adaptive trait, with a functional role in each individual organism, that is maintained and has evolved through natural selection. Historically, adaptation has been described from the time of the ancient Greek philosophers such as Empedocles and Aristotle. In 18th and 19th-century natural theology, adaptation was taken as evidence for the existence of a deity. Charles Darwin and Alfred Russel Wallace proposed instead that it was explained by natural selection. Adaptation is related to biological fitness, which governs the rate of evolution as measured by changes in allele frequencies. Often, two or more species co-adapt and co-evolve as they develop adaptations that interlock with those of the other species, such as with flowering plants and pollinating insects. In mimicry, species evolve to resemble other species; in mimicry this is a mutually beneficial co-evolution as each of a group of strongly defended species (such as wasps able to sting) come to advertise their defences in the


id: adaptation-20260505-1
file: data/en.wikipedia.org/wiki/Adaptation-1.md
category: reference
title: Adaptation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Adaptation
date_saved: 2026-05-05T07:15:02.299236+00:00
instance: kb-cron
parent: adaptation-20260505-0
summary:
=== What adaptation is === Adaptation is primarily a process rather than a physical form or part of a body. An internal parasite (such as a liver fluke) can illustrate the distinction: such a parasite may have a very simple bodily structure, but nevertheless the organism is highly adapted to its specific environment. From this we see that adaptation is not just a matter of visible traits: in such parasites critical adaptations take place in the life cycle, which is often quite complex. However, as a practical term, "adaptation" often refers to a product: those features of a species which result from the process. Many aspects of an animal or plant can be correctly called adaptations, though there are always some features whose function remains in doubt. By using the term adaptation for the evolutionary process, and adaptive trait for the bodily part or function (the product), one may distinguish the two different senses of the word. Adaptation is one of the two main processes that explain the observed diversity of species, such as the different species of Darwin's finches. The other process is speciation, in which new species arise, typically through reproductive isolation. An example widely used today to


id: adaptation-20260505-2
file: data/en.wikipedia.org/wiki/Adaptation-2.md
category: reference
title: Adaptation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Adaptation
date_saved: 2026-05-05T07:15:02.299236+00:00
instance: kb-cron
parent: adaptation-20260505-0
summary:
There is a relationship between adaptedness and the concept of fitness used in population genetics. Differences in fitness between genotypes predict the rate of evolution by natural selection. Natural selection changes the relative frequencies of alternative phenotypes, insofar as they are heritable. However, a phenotype with high adaptedness may not have high fitness. Dobzhansky mentioned the example of the Californian redwood, which is highly adapted, but a relict species in danger of extinction. Elliott Sober commented that adaptation was a retrospective concept since it implied something about the history of a trait, whereas fitness predicts a trait's future. 1. Relative fitness. The average contribution to the next generation by a genotype or a class of genotypes, relative to the contributions of other genotypes in the population. This is also known as Darwinian fitness, selection coefficient, and other terms. 2. Absolute fitness. The absolute contribution to the next generation by a genotype or a class of genotypes. Also known as the Malthusian parameter when applied to the population as a whole. 3. Adaptedness. The extent to which a phenotype fits its local ecological niche. Researchers can sometimes test this through a reciprocal transplant. Sewall Wright proposed that populations occupy adaptive peaks


id: adaptation-20260505-3
file: data/en.wikipedia.org/wiki/Adaptation-3.md
category: reference
title: Adaptation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Adaptation
date_saved: 2026-05-05T07:15:02.299236+00:00
instance: kb-cron
parent: adaptation-20260505-0
summary:
In coevolution, where the existence of one species is tightly bound up with the life of another species, new or 'improved' adaptations which occur in one species are often followed by the appearance and spread of corresponding features in the other species. In other words, each species triggers reciprocal natural selection in the other. These co-adaptational relationships are intrinsically dynamic, and may continue on a trajectory for millions of years, as has occurred in the relationship between flowering plants and pollinating insects. === Mimicry === Bates' work on Amazonian butterflies led him to develop the first scientific account of mimicry, especially the kind of mimicry which bears his name: Batesian mimicry. This is the mimicry by a palatable species of an unpalatable or noxious species (the model), gaining a selective advantage as predators avoid the model and therefore also the mimic. Mimicry is thus an anti-predator adaptation. A common example seen in temperate gardens is the hoverfly (Syrphidae), many of which—though bearing no sting—mimic the warning coloration of aculeate Hymenoptera (wasps and bees). Such mimicry does not need to be perfect to improve the survival of the palatable species. Bates, Wallace and Fritz Müller believed that Batesian and Müllerian mimicry


id: adaptation-20260505-4
file: data/en.wikipedia.org/wiki/Adaptation-4.md
category: reference
title: Adaptation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Adaptation
date_saved: 2026-05-05T07:15:02.299236+00:00
instance: kb-cron
parent: adaptation-20260505-0
summary:
=== Pre-adaptation === Pre-adaptation occurs when a population has characteristics which by chance are suited for a set of conditions not previously experienced. For example, the polyploid cordgrass Spartina townsendii is better adapted than either of its parent species to their own habitat of saline marsh and mud-flats. Among domestic animals, the White Leghorn chicken is markedly more resistant to vitamin B1 deficiency than other breeds; on a plentiful diet this makes no difference, but on a restricted diet this preadaptation could be decisive. Pre-adaptation may arise because a natural population carries a huge quantity of genetic variability. In diploid eukaryotes, this is a consequence of the system of sexual reproduction, where mutant alleles get partially shielded, for example, by genetic dominance. Microorganisms, with their huge populations, also carry a great deal of genetic variability. The first experimental evidence of the pre-adaptive nature of genetic variants in microorganisms was provided by Salvador Luria and Max Delbrück who developed the Fluctuation Test, a method to show the random fluctuation of pre-existing genetic changes that conferred resistance to bacteriophages in Escherichia coli. The word is controversial because it is teleological and the entire concept of natural selection depends on the presence of


id: adaptation-20260505-5
file: data/en.wikipedia.org/wiki/Adaptation-5.md
category: reference
title: Adaptation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Adaptation
date_saved: 2026-05-05T07:15:02.299236+00:00
instance: kb-cron
parent: adaptation-20260505-0
summary:
Adaptation raises philosophical issues concerning how biologists speak of function and purpose, as this carries implications of evolutionary history – that a feature evolved by natural selection for a specific reason – and potentially of supernatural intervention – that features and organisms exist because of a deity's conscious intentions. In his biology, Aristotle introduced teleology to describe the adaptedness of organisms, but without accepting the supernatural intention built into Plato's thinking, which Aristotle rejected. Modern biologists continue to face the same difficulty. On the one hand, adaptation is purposeful: natural selection chooses what works and eliminates what does not. On the other hand, biologists by and large reject conscious purpose in evolution. The dilemma gave rise to a famous joke by the evolutionary biologist Haldane: "Teleology is like a mistress to a biologist: he cannot live without her but he's unwilling to be seen with her in public.'" David Hull commented that Haldane's mistress "has become a lawfully wedded wife. Biologists no longer feel obligated to apologize for their use of teleological language; they flaunt it." Ernst Mayr stated that "adaptedness... is an a posteriori result rather than an a priori goal-seeking", meaning that the question of whether something is


id: aerobic-organism-20260505-0
file: data/en.wikipedia.org/wiki/Aerobic_organism-0.md
category: reference
title: Aerobic organism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Aerobic_organism
date_saved: 2026-05-05T07:15:03.488289+00:00
instance: kb-cron
parent: aerobic-organism-20260505-0
summary:
An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. The ability to exhibit aerobic respiration may yield benefits to the aerobic organism, as aerobic respiration yields more energy than anaerobic respiration. Energy production of the cell involves the synthesis of ATP by an enzyme called ATP synthase. In aerobic respiration, ATP synthase is coupled with an electron transport chain in which oxygen acts as a terminal electron acceptor. In July 2020, marine biologists reported that aerobic microorganisms (mainly), in "quasi-suspended animation", were found in organically poor sediments, up to 101.5 million years old, 250 feet below the seafloor in the South Pacific Gyre (SPG) ("the deadest spot in the ocean"), and could be the longest-living life forms ever found. == Types == Obligate aerobes need oxygen to grow. In a process known as cellular respiration, these organisms use oxygen to oxidize substrates (for example sugars and fats) and generate energy. Facultative anaerobes use oxygen if it is available, but also have anaerobic methods of energy production. Microaerophiles require oxygen for energy production, but are harmed by atmospheric concentrations of oxygen (21% O2). Aerotolerant anaerobes do not use oxygen but are not harmed


id: animal-20260505-0
file: data/en.wikipedia.org/wiki/Animal-0.md
category: reference
title: Animal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal
date_saved: 2026-05-05T07:15:04.727619+00:00
instance: kb-cron
parent: animal-20260505-0
summary:
Animals are multicellular, eukaryotic organisms belonging to the biological kingdom Animalia (). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Animals form a clade, meaning that they arose from a single common ancestor. Over 1.5 million living animal species have been described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from 8.5 μm (0.00033 in) to 33.6 m (110 ft). They have complex ecologies and interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology, and the study of animal behaviour is known as ethology. The animal kingdom is divided into five major clades, namely Porifera, Ctenophora, Placozoa, Cnidaria and Bilateria. Most living animal species belong to the clade Bilateria, a highly proliferative clade whose members have a bilaterally symmetric and significantly cephalised body plan, and the vast majority of bilaterians belong to two large clades: the protostomes, which


id: animal-20260505-1
file: data/en.wikipedia.org/wiki/Animal-1.md
category: reference
title: Animal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal
date_saved: 2026-05-05T07:15:04.727619+00:00
instance: kb-cron
parent: animal-20260505-0
summary:
Nearly all animals make use of some form of sexual reproduction. They produce haploid gametes by meiosis; the smaller, motile gametes are spermatozoa and the larger, non-motile gametes are ova. These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, and develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement. It first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm, also develops between them. These germ layers then differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction generally leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. Some animals are capable of asexual reproduction, which often results in a genetic clone of the parent. This may take place through fragmentation; budding, such as in Hydra and other cnidarians; or parthenogenesis, where fertile eggs are produced without mating, such as


id: animal-20260505-2
file: data/en.wikipedia.org/wiki/Animal-2.md
category: reference
title: Animal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal
date_saved: 2026-05-05T07:15:04.727619+00:00
instance: kb-cron
parent: animal-20260505-0
summary:
Evidence of animals is found as long ago as the Cryogenian period. 24-Isopropylcholestane (24-ipc) has been found in rocks from roughly 650 million years ago; it is only produced by sponges and pelagophyte algae. Its likely origin is from sponges based on molecular clock estimates for the origin of 24-ipc production in both groups. Analyses of pelagophyte algae consistently recover a Phanerozoic origin, while analyses of sponges recover a Neoproterozoic origin, consistent with the appearance of 24-ipc in the fossil record. The first body fossils of animals appear in the Ediacaran, represented by forms such as Charnia and Spriggina. It had long been doubted whether these fossils truly represented animals, but the discovery of the animal lipid cholesterol in fossils of Dickinsonia establishes their nature. Animals are thought to have originated under low-oxygen conditions, suggesting that they were capable of living entirely by anaerobic respiration, but as they became specialised for aerobic metabolism they became fully dependent on oxygen in their environments. Many animal phyla first appear in the fossil record during the Cambrian explosion, starting about 539 million years ago, in beds such as the Burgess Shale. Extant phyla in these rocks include molluscs, brachiopods, onychophorans, tardigrades, arthropods, echinoderms


id: animal-20260505-3
file: data/en.wikipedia.org/wiki/Animal-3.md
category: reference
title: Animal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal
date_saved: 2026-05-05T07:15:04.727619+00:00
instance: kb-cron
parent: animal-20260505-0
summary:
The remaining animals, the great majority—comprising some 29 phyla and over a million species—form the Bilateria clade, which have a bilaterally symmetric body plan. The Bilateria are triploblastic, with three well-developed germ layers, and their tissues form distinct organs. The digestive chamber has two openings, a mouth and an anus, and in the Nephrozoa there is an internal body cavity, a coelom or pseudocoelom. These animals have a head end (anterior) and a tail end (posterior), a back (dorsal) surface and a belly (ventral) surface, and a left and a right side. A modern consensus phylogenetic tree for the Bilateria is shown below. Having a front end means that this part of the body encounters stimuli, such as food, favouring cephalisation, the development of a head with sense organs and a mouth. Many bilaterians have a combination of circular muscles that constrict the body, making it longer, and an opposing set of longitudinal muscles, that shorten the body; these enable soft-bodied animals with a hydrostatic skeleton to move by peristalsis. They also have a gut that extends through the basically cylindrical body from mouth to anus. Many bilaterian phyla have primary larvae which swim with cilia and have an apical


id: animal-20260505-4
file: data/en.wikipedia.org/wiki/Animal-4.md
category: reference
title: Animal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Animal
date_saved: 2026-05-05T07:15:04.727619+00:00
instance: kb-cron
parent: animal-20260505-0
summary:
The human population exploits a large number of other animal species for food, both of domesticated livestock species in animal husbandry and, mainly at sea, by hunting wild species. Marine fish of many species are caught commercially for food. A smaller number of species are farmed commercially. Humans and their livestock make up more than 90% of the biomass of all terrestrial vertebrates, and almost as much as all insects combined. Invertebrates including cephalopods, crustaceans, insects—principally bees and silkworms—and bivalve or gastropod molluscs are hunted or farmed for food, fibres. Chickens, cattle, sheep, pigs, and other animals are raised as livestock for meat across the world. Animal fibres such as wool and silk are used to make textiles, while animal sinews have been used as lashings and bindings, and leather is widely used to make shoes and other items. Animals have been hunted and farmed for their fur to make items such as coats and hats. Dyestuffs including carmine (cochineal), shellac, and kermes have been made from the bodies of insects. Working animals including cattle and horses have been used for work and transport from the first days of agriculture. Animals such as the fruit fly Drosophila melanogaster serve a


id: archaea-20260505-0
file: data/en.wikipedia.org/wiki/Archaea-0.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
Archaea ( ar-KEE-ə) is a domain of organisms. Traditionally, Archaea included only its prokaryotic members, but has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even though the domain Archaea cladistically includes eukaryotes, the term archaea (sing. archaeon ar-KEE-on; from Ancient Greek ἀρχαῖον arkhaîon 'ancient') in English still generally refers specifically to prokaryotic members of Archaea. Archaea were initially classified as bacteria, receiving the name archaebacteria (, in the Archaebacteria kingdom), but this term has fallen out of use. Archaeal cells have unique properties distinguishing them from Bacteria and Eukaryota, including: cell membranes made of ether-linked lipids; metabolisms such as methanogenesis; and a unique motility structure known as an archaellum. Archaea are further divided into multiple recognized phyla. Classification is difficult because most have not been isolated in a laboratory and have been identified only by their gene sequences in environmental samples. It is unknown whether they can produce endospores. Archaea are often similar to bacteria in size and shape, although a few have very different shapes, such as the flat, square cells of Haloquadratum walsbyi. Despite this, archaea possess genes and several metabolic pathways that are more closely related to those of


id: archaea-20260505-1
file: data/en.wikipedia.org/wiki/Archaea-1.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
The classification of archaea, and of prokaryotes in general, is a rapidly moving and contentious field. Current classification systems aim to organize archaea into groups of organisms that share structural features and common ancestors. These classifications rely heavily on the use of the sequence of ribosomal RNA genes to reveal relationships among organisms (molecular phylogenetics). Most of the culturable and well-investigated species of archaea are members of two main kingdoms, the Methanobacteriati and the Thermoproteati (formerly TACK). Other groups have been tentatively created, such as the peculiar species Nanoarchaeum equitans – discovered in 2003 and assigned its own phylum, the Nanoarchaeota (reassigned to Nanobdellota in 2023). A new phylum "Korarchaeota" (now Thermoproteota) has also been proposed, containing a small group of unusual thermophilic species sharing features of both the main phyla. Other detected species of archaea are only distantly related to any of these groups, such as the Archaeal Richmond Mine acidophilic nanoorganisms (ARMAN, comprising Micrarchaeota and Parvarchaeota), which were discovered in 2006 and are some of the smallest organisms known. A superphylum – "TACK" (now kingdom Thermoproteati) – which includes the Thaumarchaeota (now Nitrososphaerota), "Augarchaeota", Crenarchaeota (now Thermoproteota), and "Korarchaeota" (now Thermoproteota) was proposed in 2011 to be related


id: archaea-20260505-2
file: data/en.wikipedia.org/wiki/Archaea-2.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
Archaea were split off as a third domain because of the large differences in their ribosomal RNA structure. The particular molecule 16S rRNA is key to the production of proteins in all organisms. Because this function is so central to life, organisms with mutations in their 16S rRNA are unlikely to survive, leading to great (but not absolute) stability in the structure of this polynucleotide over generations. 16S rRNA is large enough to show organism-specific variations, but still small enough to be compared quickly. In 1977, Carl Woese, a microbiologist studying the genetic sequences of organisms, developed a new comparison method that involved splitting the RNA into fragments that could be sorted and compared with other fragments from other organisms. The more similar the patterns between species, the more closely they are related. Woese used his new rRNA comparison method to categorize and contrast different organisms. He compared a variety of species and happened upon a group of methanogens with rRNA vastly different from any known prokaryotes or eukaryotes. These methanogens were much more similar to each other than to other organisms, leading Woese to propose the new domain of Archaea. His experiments showed that the archaea were genetically more


id: archaea-20260505-3
file: data/en.wikipedia.org/wiki/Archaea-3.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
The evolutionary relationship between archaea and eukaryotes remains unclear. Aside from the similarities in cell structure and function that are discussed below, many genetic trees group the two. Complicating factors include claims that the relationship between eukaryotes and the archaeal phylum Thermoproteota is closer than the relationship between the Methanobacteriati and the phylum Thermoproteota and the presence of archaea-like genes in certain bacteria, such as Thermotoga maritima, from horizontal gene transfer. The standard hypothesis states that the ancestor of the eukaryotes diverged early from the Archaea, and that eukaryotes arose through symbiogenesis, the fusion of an archaean and a eubacterium, which formed the mitochondria; this hypothesis explains the genetic similarities between the groups. The eocyte hypothesis instead posits that Eukaryota emerged relatively late from the Archaea. A lineage of archaea discovered in 2015, Lokiarchaeum (of the proposed new phylum "Lokiarchaeota"), named for a hydrothermal vent called Loki's Castle in the Arctic Ocean, was found to be the most closely related to eukaryotes known at that time. It has been called a transitional organism between prokaryotes and eukaryotes. Several sister phyla of "Lokiarchaeota" have since been found ("Thorarchaeota", "Odinarchaeota", "Heimdallarchaeota"), all together comprising a newly proposed supergroup "Asgard". Details of the


id: archaea-20260505-4
file: data/en.wikipedia.org/wiki/Archaea-4.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
They have membranes composed of glycerol-ether lipids, whereas bacteria and eukaryotes have membranes composed mainly of glycerol-ester lipids. The difference is the type of bond that joins the lipids to the glycerol moiety; the two types are shown in yellow in the figure at the right. In ester lipids, this is an ester bond, whereas in ether lipids this is an ether bond. The stereochemistry of the archaeal glycerol moiety is the mirror image of that found in other organisms. The glycerol moiety can occur in two forms that are mirror images of one another, called enantiomers. Just as a right hand does not fit easily into a left-handed glove, enantiomers of one type generally cannot be used or made by enzymes adapted for the other. The archaeal phospholipids are built on a backbone of sn-glycerol-1-phosphate, which is an enantiomer of sn-glycerol-3-phosphate, the phospholipid backbone found in bacteria and eukaryotes. This suggests that archaea use entirely different enzymes for synthesizing phospholipids as compared to bacteria and eukaryotes. Such enzymes developed very early in life's history, indicating an early split from the other two domains. Archaeal lipid tails differ from those of other organisms in that they are based upon long


id: archaea-20260505-5
file: data/en.wikipedia.org/wiki/Archaea-5.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
Archaea are genetically distinct from bacteria and eukaryotes, with up to 15% of the proteins encoded by any one archaeal genome being unique to the domain, although most of these unique genes have no known function. Of the remainder of the unique proteins that have an identified function, most belong to the Methanobacteriati and are involved in methanogenesis. The proteins that archaea, bacteria and eukaryotes share form a common core of cell function, relating mostly to transcription, translation, and nucleotide metabolism. Other characteristic archaeal features are the organization of genes of related function – such as enzymes that catalyze steps in the same metabolic pathway into novel operons, and large differences in tRNA genes and their aminoacyl tRNA synthetases. Transcription in archaea more closely resembles eukaryotic than bacterial transcription, with the archaeal RNA polymerase being very close to its equivalent in eukaryotes, while archaeal translation shows signs of both bacterial and eukaryotic equivalents. Although archaea have only one type of RNA polymerase, its structure and function in transcription seems to be close to that of the eukaryotic RNA polymerase II, with similar protein assemblies (the general transcription factors) directing the binding of the RNA polymerase to a gene's promoter, but


id: archaea-20260505-6
file: data/en.wikipedia.org/wiki/Archaea-6.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
Archaea reproduce asexually by binary or multiple fission, fragmentation, or budding; mitosis and meiosis do not occur, so if a species of archaea exists in more than one form, all have the same genetic material. Cell division is controlled in a cell cycle; after the cell's chromosome is replicated and the two daughter chromosomes separate, the cell divides. In the genus Sulfolobus, the cycle has characteristics that are similar to both bacterial and eukaryotic systems. The chromosomes replicate from multiple starting points (origins of replication) using DNA polymerases that resemble the equivalent eukaryotic enzymes. In Methanobacteriati the cell division protein FtsZ, which forms a contracting ring around the cell, and the components of the septum that is constructed across the center of the cell, are similar to their bacterial equivalents. In cren- and thaumarchaea, the cell division machinery Cdv fulfills a similar role. This machinery is related to the eukaryotic ESCRT-III machinery which, while best known for its role in cell sorting, also has been seen to fulfill a role in separation between divided cell, suggesting an ancestral role in cell division. Both bacteria and eukaryotes, but not archaea, make spores. Some species of Haloarchaea undergo phenotypic switching and grow


id: archaea-20260505-7
file: data/en.wikipedia.org/wiki/Archaea-7.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
Archaea exist in a broad range of habitats, are recognized as a major part of global ecosystems, and may represent about 20% of microbial cells in the oceans. However, the first-discovered archaeans were extremophiles. Indeed, some archaea survive high temperatures, often above 100 °C (212 °F), as found in geysers, black smokers, and oil wells. Other common habitats include very cold habitats and highly saline, acidic, or alkaline water, but archaea include mesophiles that grow in mild conditions, in swamps and marshland, sewage, the oceans, the intestinal tract of animals, and soils. Similar to PGPR, Archaea are considered a source of plant growth promotion as well. Extremophile archaea are members of four main physiological groups. These are the halophiles, thermophiles, alkaliphiles, and acidophiles. These groups are not comprehensive or phylum-specific, nor are they mutually exclusive, since some archaea belong to several groups. Nonetheless, they are a useful starting point for classification. Halophiles, including the genus Halobacterium, live in extremely saline environments such as salt lakes and outnumber their bacterial counterparts at salinities greater than 20–25%. Thermophiles grow best at temperatures above 45 °C (113 °F), in places such as hot springs; hyperthermophilic archaea grow optimally at temperatures greater than 80


id: archaea-20260505-8
file: data/en.wikipedia.org/wiki/Archaea-8.md
category: reference
title: Archaea
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Archaea
date_saved: 2026-05-05T07:15:06.056512+00:00
instance: kb-cron
parent: archaea-20260505-0
summary:
==== Commensalism ==== Some archaea are commensals, benefiting from an association without helping or harming the other organism. For example, the methanogen Methanobrevibacter smithii is by far the most common archaean in the human flora, making up about one in ten of the prokaryotes in the human gut. In termites and in humans, these methanogens may in fact be mutualists, interacting with other microbes in the gut to aid digestion. Archaean communities associate with a range of other organisms, such as on the surface of corals, and in the region of soil that surrounds plant roots (the rhizosphere). ==== Parasitism ==== Although Archaea do not have a historical reputation of being pathogens, Archaea are often found with similar genomes to more common pathogens like E. coli, showing metabolic links and evolutionary history with today's pathogens. Archaea have been inconsistently detected in clinical studies because of the lack of categorization of Archaea into more specific species. The reduced genome of Candidatus Sukunaarchaeum mirabile suggests it is a specialized parasite highly dependant on its dinoflagellate host. == Significance in technology and industry == Extremophile archaea, particularly those resistant either to heat or to extremes of acidity and alkalinity, are a source of


id: autotroph-20260505-0
file: data/en.wikipedia.org/wiki/Autotroph-0.md
category: reference
title: Autotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Autotroph
date_saved: 2026-05-05T07:15:07.302269+00:00
instance: kb-cron
parent: autotroph-20260505-0
summary:
An autotroph is an organism that can convert abiotic sources of energy into energy stored in organic compounds, which can be used by other organisms. Autotrophs produce complex organic compounds (such as carbohydrates, fats, and proteins) using carbon from simple substances such as carbon dioxide, generally using energy from light or inorganic chemical reactions. Autotrophs do not need a living source of carbon or energy and are the producers in a food chain, such as plants on land or algae in water. Autotrophs can reduce carbon dioxide to make organic compounds for biosynthesis and as stored chemical fuel. Most autotrophs use water as the reducing agent, but some can use other hydrogen compounds such as hydrogen sulfide. The primary producers can convert the energy in the light (phototroph and photoautotroph) or the energy in inorganic chemical compounds (chemotrophs or chemolithotrophs) to build organic molecules, which are usually accumulated in the form of biomass and will be used as carbon and energy source by other organisms (e.g. heterotrophs and mixotrophs). The photoautotrophs are the main primary producers, converting the energy of the light into chemical energy through photosynthesis, ultimately building organic molecules from carbon dioxide, an inorganic carbon source. Examples of


id: autotroph-20260505-1
file: data/en.wikipedia.org/wiki/Autotroph-1.md
category: reference
title: Autotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Autotroph
date_saved: 2026-05-05T07:15:07.302269+00:00
instance: kb-cron
parent: autotroph-20260505-0
summary:
Without primary producers, organisms that are capable of producing energy on their own, the biological systems of Earth would be unable to sustain themselves. Plants, along with other primary producers, produce the energy that other living beings consume, and the oxygen that they breathe. It is thought that the first organisms on Earth were primary producers located on the ocean floor. Autotrophs are fundamental to the food chains of all ecosystems in the world. They take energy from the environment in the form of sunlight or inorganic chemicals and use it to create fuel molecules such as carbohydrates. This mechanism is called primary production. Other organisms, called heterotrophs, take in autotrophs as food to carry out functions necessary for their life. Thus, heterotrophs – all animals, almost all fungi, and most bacteria and protozoa – depend on autotrophs, or primary producers, for the raw materials and fuel they need. Heterotrophs obtain energy by breaking down carbohydrates or oxidizing organic molecules (carbohydrates, fats, and proteins) obtained in food. Carnivorous organisms rely on autotrophs indirectly, as the nutrients obtained from their heterotrophic prey come from autotrophs they have consumed. Most ecosystems are supported by the autotrophic primary production of plants and cyanobacteria


id: bacteria-20260505-0
file: data/en.wikipedia.org/wiki/Bacteria-0.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
Bacteria are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit the air, soil, water, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria play a vital role in many stages of the nutrient cycle by recycling nutrients and the fixation of nitrogen from the atmosphere. The nutrient cycle includes the decomposition of dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. Bacteria also live in mutualistic, commensal and parasitic relationships with plants and animals. Most bacteria have not been characterised and there are many species that cannot be grown in the laboratory. The study of bacteria is known as bacteriology, a branch of microbiology. Like all animals, humans carry vast numbers (approximately 1013 to 1014) of bacteria. Most are in the gut, though there are


id: bacteria-20260505-1
file: data/en.wikipedia.org/wiki/Bacteria-1.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
== Habitat == Bacteria are ubiquitous, living in every possible habitat on the planet including soil, underwater, deep in Earth's crust and even such extreme environments as acidic hot springs and radioactive waste. There are thought to be approximately 2×1030 bacteria on Earth, forming a biomass that is only exceeded by plants. They are abundant in lakes and oceans, in arctic ice, and geothermal springs where they provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulphide and methane, to energy. They live on and in plants and animals. Most do not cause diseases, are beneficial to their environments, and are essential for life. The soil is a rich source of bacteria and a few grams contain around a thousand million of them. They are all essential to soil ecology, breaking down toxic waste and recycling nutrients. They are even found in the atmosphere and one cubic metre of air holds around one hundred million bacterial cells. The oceans and seas harbour around 3 × 1026 bacteria which provide up to 50% of the oxygen humans breathe. Only around 2% of bacterial species have been fully studied. == Morphology == Size. Bacteria display a wide


id: bacteria-20260505-2
file: data/en.wikipedia.org/wiki/Bacteria-2.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
Bacteria do not have a membrane-bound nucleus, and their genetic material is typically a single circular bacterial chromosome of DNA located in the cytoplasm in an irregularly shaped body called the nucleoid. The nucleoid contains the chromosome with its associated proteins and RNA. Like all other organisms, bacteria contain ribosomes for the production of proteins, but the structure of the bacterial ribosome is different from that of eukaryotes and archaea. Its translation process is also different. Some bacteria produce intracellular nutrient storage granules, such as glycogen, polyphosphate, sulfur or polyhydroxyalkanoates. Bacteria such as the photosynthetic cyanobacteria, produce internal gas vacuoles, which they use to regulate their buoyancy, allowing them to move up or down into water layers with different light intensities and nutrient levels. === Extracellular structures === Around the outside of the cell membrane is the cell wall. Bacterial cell walls are made of peptidoglycan (also called murein), which is made from polysaccharide chains cross-linked by peptides containing D-amino acids. Bacterial cell walls are different from the cell walls of plants and fungi, which are made of cellulose and chitin, respectively. The cell wall of bacteria is also distinct from that of archaea, which do not contain peptidoglycan. The


id: bacteria-20260505-3
file: data/en.wikipedia.org/wiki/Bacteria-3.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
Bacteria exhibit an extremely wide variety of metabolic types. The distribution of metabolic traits within a group of bacteria has traditionally been used to define their taxonomy, but these traits often do not correspond with modern genetic classifications. Bacterial metabolism is classified into nutritional groups on the basis of three major criteria: the source of energy, the electron donors used, and the source of carbon used for growth. Phototrophic bacteria derive energy from light using photosynthesis, while chemotrophic bacteria breaking down chemical compounds through oxidation, driving metabolism by transferring electrons from a given electron donor to a terminal electron acceptor in a redox reaction. Chemotrophs are further divided by the types of compounds they use to transfer electrons. Bacteria that derive electrons from inorganic compounds such as hydrogen, carbon monoxide, or ammonia are called lithotrophs, while those that use organic compounds are called organotrophs. Still, more specifically, aerobic organisms use oxygen as the terminal electron acceptor, while anaerobic organisms use other compounds such as nitrate, sulfate, or carbon dioxide. Many bacteria, called heterotrophs, derive their carbon from other organic carbon. Others, such as cyanobacteria and some purple bacteria, are autotrophic, meaning they obtain cellular carbon by fixing carbon dioxide. In


id: bacteria-20260505-4
file: data/en.wikipedia.org/wiki/Bacteria-4.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
Most bacteria have a single circular chromosome that can range in size from only 160,000 base pairs in the endosymbiotic bacteria Carsonella ruddii, to 12,200,000 base pairs (12.2 Mbp) in the soil-dwelling bacteria Sorangium cellulosum, to 16.0 Mbp in another soil-dwelling bacteria, Minicystis rosea. There are many exceptions to this; for example, some Streptomyces and Borrelia species contain a single linear chromosome, while some bacteria including species of Vibrio contain more than one chromosome. Some bacteria contain plasmids, small extra-chromosomal molecules of DNA that may contain genes for various useful functions such as antibiotic resistance, metabolic capabilities, or various virulence factors. Whether they have a single chromosome or more than one, almost all bacteria have a haploid genome. This means that they have only one copy of each gene encoding proteins. This is in contrast to eukaryotes, which are diploid or polyploid, meaning they have two or more copies of each gene. This means that unlike humans, who may still be able to create a protein if the gene becomes mutated (since the human genome has an extra copy in each cell), a bacterium will be completely unable to create the protein if its gene incurs an inactivating mutation. Bacterial


id: bacteria-20260505-5
file: data/en.wikipedia.org/wiki/Bacteria-5.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
A few bacteria have chemical systems that generate light. This bioluminescence often occurs in bacteria that live in association with fish, and the light probably serves to attract fish or other large animals. Bacteria often function as multicellular aggregates known as biofilms, exchanging a variety of molecular signals for intercell communication and engaging in coordinated multicellular behaviour. The communal benefits of multicellular cooperation include a cellular division of labour, accessing resources that cannot effectively be used by single cells, collectively defending against antagonists, and optimising population survival by differentiating into distinct cell types. For example, bacteria in biofilms can have more than five hundred times the increased resistance to antibacterial agents than individual "planktonic" bacteria of the same species. One type of intercellular communication by a molecular signal is called quorum sensing. Quorum sensing determines whether the local population is dense enough to support investment in processes that are only successful if large numbers of similar organisms behave similarly, such as excreting digestive enzymes or emitting light. Quorum sensing enables bacteria to coordinate gene expression and to produce, release, and detect autoinducers or pheromones that accumulate with the growth in cell population. == Classification and identification == Classification seeks to


id: bacteria-20260505-6
file: data/en.wikipedia.org/wiki/Bacteria-6.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
=== Valid phyla === The following phyla have been validly published according to the Prokaryotic Code; phyla that do not belong to any kingdom are shown in bold: === Candidate phyla === The following phyla have been proposed, but have not been validly published according to the Prokaryotic Code; phyla that do not belong to any kingdom are shown in bold: == Interactions with other organisms == Despite their apparent simplicity, bacteria can form complex associations with other organisms. These symbiotic associations can be divided into parasitism, mutualism and commensalism. === Commensals === The word "commensalism" is derived from the word "commensal", meaning "eating at the same table" and all plants and animals are colonised by commensal bacteria. In humans and other animals, trillions of them live on the skin, the airways, the gut and other orifices. Referred to as "normal flora", or "commensals", these bacteria usually cause no harm but may occasionally invade other sites of the body and cause infection. Escherichia coli is a commensal in the human gut but can cause urinary tract infections. Similarly, streptococci, which are part of the normal flora of the human mouth, can cause heart disease. === Predators === Some species of


id: bacteria-20260505-7
file: data/en.wikipedia.org/wiki/Bacteria-7.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
Each species of pathogen has a characteristic spectrum of interactions with its human hosts. Some organisms, such as Staphylococcus or Streptococcus, can cause skin infections, pneumonia, meningitis and sepsis, a systemic inflammatory response producing shock, massive vasodilation and death. Yet these organisms are also part of the normal human flora and usually exist on the skin or in the nose without causing any disease at all. Other organisms invariably cause disease in humans, such as Rickettsia, which are obligate intracellular parasites able to grow and reproduce only within the cells of other organisms. One species of Rickettsia causes typhus, while another causes Rocky Mountain spotted fever. Chlamydia, another phylum of obligate intracellular parasites, contains species that can cause pneumonia or urinary tract infection and may be involved in coronary heart disease. Some species, such as Pseudomonas aeruginosa, Burkholderia cenocepacia, and Mycobacterium avium, are opportunistic pathogens and cause disease mainly in people who are immunosuppressed or have cystic fibrosis. Some bacteria produce toxins, which cause diseases. These are endotoxins, which come from broken bacterial cells, and exotoxins, which are produced by bacteria and released into the environment. The bacterium Clostridium botulinum for example, produces a powerful exotoxin that cause respiratory paralysis,


id: bacteria-20260505-8
file: data/en.wikipedia.org/wiki/Bacteria-8.md
category: reference
title: Bacteria
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bacteria
date_saved: 2026-05-05T07:15:08.686083+00:00
instance: kb-cron
parent: bacteria-20260505-0
summary:
Bacteria were first observed by the Dutch microscopist Antonie van Leeuwenhoek in 1676, using a single-lens microscope of his own design. Leeuwenhoek did not recognize bacteria as a distinct category of microorganisms, referring to all microorganisms that he observed, including bacteria, protists, and microscopic animals, as animalcules. He published his observations in a series of letters to the Royal Society of London. Bacteria were Leeuwenhoek's most remarkable microscopic discovery. Their size was just at the limit of what his simple lenses could resolve, and, in one of the most striking hiatuses in the history of science, no one else would see them again for over a century. His observations also included protozoans, and his findings were looked at again in the light of the more recent findings of cell theory. Christian Gottfried Ehrenberg introduced the word "bacterium" in 1828. In fact, his Bacterium was a genus that contained non-spore-forming rod-shaped bacteria, as opposed to Bacillus, a genus of spore-forming rod-shaped bacteria defined by Ehrenberg in 1835. Louis Pasteur demonstrated in 1859 that the growth of microorganisms causes the fermentation process and that this growth is not due to spontaneous generation (yeasts and molds, commonly associated with fermentation, are not bacteria,


id: biofact-biology-20260505-0
file: data/en.wikipedia.org/wiki/Biofact_(biology)-0.md
category: reference
title: Biofact (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biofact_(biology)
date_saved: 2026-05-05T07:15:09.903564+00:00
instance: kb-cron
parent: biofact-biology-20260505-0
summary:
In biology, a biofact is dead material of a once-living organism. In 1943, the protozoologist Bruno M. Klein of Vienna (1891–1968) coined the term in his article Biofakt und Artefakt in the microscopy journal Mikrokosmos, though at that time it was not adopted by the scientific community. Klein's concept of biofact stressed the dead materials produced by living organisms as sheaths, such as shells. The word biofact is now widely used in the zoo/aquarium world, but was first used by Lisbeth Bornhofft in 1993 in the Education Department at the New England Aquarium, Boston, to refer to preserved items such as animal bones, skins, molts and eggs. The Accreditation Standards and Related Policies of the Association of Zoos and Aquariums states that biofacts can be useful education tools, and are preferable to live animals because of potential ethical considerations. == See also == Biofact (archaeology) == References ==


id: bioliteracy-20260505-0
file: data/en.wikipedia.org/wiki/Bioliteracy-0.md
category: reference
title: Bioliteracy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Bioliteracy
date_saved: 2026-05-05T07:15:11.133438+00:00
instance: kb-cron
parent: bioliteracy-20260505-0
summary:
Bioliteracy is the ability to understand and engage with biological topics. The concept is used particularly in the contexts of biotechnology and biodiversity. == Description == In the biotechnology context, bioliteracy is considered important for promoting the biotechnology industry and the development of biological engineering products. It has also been defined as "the concept of imbuing people, personnel, or teams with an understanding of and comfort with biology and biotechnology." The use in the context of biodiversity is somewhat distinct, focusing on improving awareness of different organisms with the goal of conservation. Citizen science initiatives, such as iNaturalist, are considered effective ways to increase bioliteracy, engaging students with the direct observation of nature. == References ==


id: biological-target-20260505-0
file: data/en.wikipedia.org/wiki/Biological_target-0.md
category: reference
title: Biological target
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biological_target
date_saved: 2026-05-05T07:15:12.337114+00:00
instance: kb-cron
parent: biological-target-20260505-0
summary:
A biological target is anything within a living organism to which some other entity (like an endogenous ligand or a drug) is directed and/or binds, resulting in a change in its behavior or function. Examples of common classes of biological targets are proteins and nucleic acids. The definition is context-dependent, and can refer to the biological target of a pharmacologically active drug compound, the receptor target of a hormone (like insulin), or some other target of an external stimulus. Biological targets are most commonly proteins such as enzymes, ion channels, and receptors, but in recent years DNA's and RNA's became more targeted than in the past. == Mechanism == The external stimulus (i.e., the drug or ligand) physically binds to ("hits") the biological target. The interaction between the substance and the target may be: noncovalent – A relatively weak interaction between the stimulus and the target where no chemical bond is formed between the two interacting partners and hence the interaction is completely reversible. reversible covalent – A chemical reaction occurs between the stimulus and target in which the stimulus becomes chemically bonded to the target, but the reverse reaction also readily occurs in which the bond can be broken.


id: biomarker-20260505-0
file: data/en.wikipedia.org/wiki/Biomarker-0.md
category: reference
title: Biomarker
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biomarker
date_saved: 2026-05-05T07:15:13.536230+00:00
instance: kb-cron
parent: biomarker-20260505-0
summary:
In biomedical contexts, a biomarker, or biological marker, is a measurable indicator of some biological state or condition. Biomarkers are often measured and evaluated using blood, urine, or soft tissues to examine normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention. Biomarkers are used in many scientific fields. == Medicine == Biomarkers used in the medical field, are a part of a relatively new clinical toolset categorized by their clinical applications. The four main classes are molecular, physiologic, histologic and radiographic biomarkers. All four types of biomarkers have a clinical role in narrowing or guiding treatment decisions and follow a sub-categorization of being either predictive, prognostic, or diagnostic. === Predictive === Predictive molecular, cellular, or imaging biomarkers that pass validation can serve as a method of predicting clinical outcomes. Predictive biomarkers are used to help optimize ideal treatments, and often indicate the likelihood of benefiting from a specific therapy. For example, in metastatic colorectal cancer, predictive biomarkers can serve as a way of evaluating and improving patient survival rates and in the individual case by case scenario, they can serve as a way of sparing patients from needless toxicity that arises from cancer treatment plans. Common examples


id: biomarker-20260505-1
file: data/en.wikipedia.org/wiki/Biomarker-1.md
category: reference
title: Biomarker
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biomarker
date_saved: 2026-05-05T07:15:13.536230+00:00
instance: kb-cron
parent: biomarker-20260505-0
summary:
== Research == Biomarkers for precision medicine are a part of a relatively new behavioral and clinical toolset. In terms of the behavioral toolset, biomarkers are increasingly being used to motivate health behavior change, particularly in diabetes, cardiovascular diseases, and obesity research. Most research to date uses biomarkers that are easily measured, including weight, blood pressure, and glucose; these biomarkers may reflect the impacts of diet, physical activity, and smoking reduction. However, the methods by which feedback from biomarkers are used in intervention research are varied, and their effectiveness remains unclear. In reference to the clinical toolset, only two predictive biomarkers are implemented clinically in the case of metastatic colorectal cancer. In this case, the lack of data beyond retrospective studies and successful biomarker-driven approaches may be a factor in using biomarker studies due to the attrition of subjects in clinical trials. The field of biomarker research is also expanding to include a combinatorial approach to identifying biomarkers from multiple sources. Combining biomarkers from various data allows for the possibility of developing panels that evaluate treatment response based on many biomarkers at a single time. One such area of expanding research in multiple-factor biomarkers is mitochondrial DNA sequencing. Mutations in


id: biomarker-20260505-2
file: data/en.wikipedia.org/wiki/Biomarker-2.md
category: reference
title: Biomarker
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biomarker
date_saved: 2026-05-05T07:15:13.536230+00:00
instance: kb-cron
parent: biomarker-20260505-0
summary:
Biomarkers are being used to identify the effects of water contamination on aquatic organisms. Benthic macro-invertebrates reside in the sediment on the bottoms of streams, which is where many contaminants settle. These organisms have high exposure to the contamination, which makes them good study species when detecting pollutant concentrations and pollution impacts on an ecosystem. There are a variety of biomarkers within an aquatic organism that can be measured, depending on the contaminant or the response in question. There are also a variety of contaminants within water bodies. To analyze the impact of a pollutant on an organism, the biomarker must respond to a specific contaminant within a specific time frame or at a certain concentration. The biomarkers used to detect pollution in aquatic organisms can be enzymatic or non-enzymatic. Rachel Carson, the author of Silent Spring, raised the issue of using organochlorine pesticides and discussed the possible negative effects that said pesticides have on living organisms. Her book raised ethical issues against chemical corporations that were controlling the general reception of the effect of pesticides on the environment, which pioneered the need for ecotoxicological studies. Ecotoxicologial studies could be considered the precursors to biomarker studies. Biomarkers are used to


id: biosignal-20260505-0
file: data/en.wikipedia.org/wiki/Biosignal-0.md
category: reference
title: Biosignal
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biosignal
date_saved: 2026-05-05T07:15:14.749681+00:00
instance: kb-cron
parent: biosignal-20260505-0
summary:
A biosignal is any signal in a living organism that can be continually measured and monitored. The term biosignal is often used to refer to bioelectrical signals, but it may refer to both electrical and non-electrical signals. The usual understanding is to refer only to time-varying signals, although spatial parameter variations (e.g. the nucleotide sequence determining the genetic code) are sometimes subsumed as well. == Electrical biosignals == Electrical biosignals, or bioelectrical time signals, usually refers to the change in electric current produced by the sum of an electrical potential difference across a specialized tissue, organ or cell system like the nervous system. Thus, among the best-known bioelectrical signals are: Electroencephalogram (EEG) Electrocardiogram (ECG) Electromyogram (EMG) Electrooculogram (EOG) Electroretinogram (ERG) Electrogastrogram (EGG) Galvanic skin response (GSR) or electrodermal activity (EDA) EEG, ECG, EOG and EMG are measured with a differential amplifier which registers the difference between two electrodes attached to the skin. However, the galvanic skin response measures electrical resistance and the Magnetoencephalography (MEG) measures the magnetic field induced by electrical currents (electroencephalogram) of the brain. With the development of methods for remote measurement of electric fields using new sensor technology, electric biosignals such as EEG and ECG can be


id: biosignature-20260505-0
file: data/en.wikipedia.org/wiki/Biosignature-0.md
category: reference
title: Biosignature
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biosignature
date_saved: 2026-05-05T07:15:15.960639+00:00
instance: kb-cron
parent: biosignature-20260505-0
summary:
A biosignature is a phenomenon that can be explained by biological processes where all possible abiotic causes of this phenomenon have been eliminated. This term is mainly used in the field of astrobiology in the search for past or present extraterrestrial life, from planets and moons in the Solar System to exoplanets. Candidate biosignatures strongly indicate some of the earliest known life forms, aid studies of the origin of life on Earth as well as the possibility of life on Mars, Venus and elsewhere in the universe. == History == The term "biosignature" and its definition have evolved over time. In the 1960s, the phrase "life detection" was used as seen in two Nature papers "A physical basis for life detection experiments," by James. E. Lovelock (1965) and "Signs of Life: Criterion-system of exobiology," by Joshua Lederberg (1965). In 1973, Joon H. Rho used the term "biomarker" in his paper, "A search for porphyrin biomarkers in nonesuch shale and extraterrestrial samples" to describe a fossil organic compound that can be traced back to a specific organism. In medicine, biomarker (medicine) has a different definition. In 1995, the term biosignature was first used by the NASA Exobiology Program office (now the


id: biosignature-20260505-1
file: data/en.wikipedia.org/wiki/Biosignature-1.md
category: reference
title: Biosignature
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biosignature
date_saved: 2026-05-05T07:15:15.960639+00:00
instance: kb-cron
parent: biosignature-20260505-0
summary:
==== Human limitations ==== Observational or technological limitations may also limit the detectability of a potential biosignature. Telescope resolution maybe insufficient to resolve spectral features needed to distinguish between biological signals and false positives. In addition, observatories and telescopes are designed by multidisciplinary teams, resulting in instrumentation that reflects compromises among a variety of scientific priorities. As a result, optimizing instruments for biosignature detection may requires trade-offs with capabilities aimed at other science goals. == General examples == === Geomicrobiology === The ancient record on Earth provides an opportunity to see what geochemical signatures are produced by microbial life and how these signatures are preserved over geologic time. Some related disciplines such as geochemistry, geobiology, and geomicrobiology often use biosignatures to determine if living organisms are or were present in a sample. These possible biosignatures include: (a) microfossils and stromatolites; (b) molecular structures (biomarkers) and isotopic compositions of carbon, nitrogen and hydrogen in organic matter; (c) multiple sulfur and oxygen isotope ratios of minerals; and (d) abundance relationships and isotopic compositions of redox-sensitive metals (e.g., Fe, Mo, Cr, and rare earth elements). For example, the particular fatty acids measured in a sample can indicate which types of bacteria and archaea


id: biosignature-20260505-2
file: data/en.wikipedia.org/wiki/Biosignature-2.md
category: reference
title: Biosignature
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biosignature
date_saved: 2026-05-05T07:15:15.960639+00:00
instance: kb-cron
parent: biosignature-20260505-0
summary:
=== Atmospheric === The atmospheric properties of exoplanets are of particular importance, as atmospheres provide the most likely observables for the near future, including habitability indicators and biosignatures. Over billions of years, the processes of life on a planet would result in a mixture of chemicals unlike anything that could form in an ordinary chemical equilibrium. For example, large amounts of oxygen and small amounts of methane are generated by life on Earth. An exoplanet's color—or reflectance spectrum—can also be used as a biosignature due to the effect of pigments that are uniquely biologic in origin such as the pigments of phototrophic and photosynthetic life forms. Scientists use the Earth as an example of this when looked at from far away (see Pale Blue Dot) as a comparison to worlds observed outside of the Solar System. Ultraviolet radiation on life forms could also induce biofluorescence in visible wavelengths that may be detected by the new generation of space observatories under development. Some scientists have reported methods of detecting hydrogen and methane in extraterrestrial atmospheres. Habitability indicators and biosignatures must be interpreted within a planetary and environmental context. For example, the presence of oxygen and methane together could indicate the kind


id: biosignature-20260505-3
file: data/en.wikipedia.org/wiki/Biosignature-3.md
category: reference
title: Biosignature
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biosignature
date_saved: 2026-05-05T07:15:15.960639+00:00
instance: kb-cron
parent: biosignature-20260505-0
summary:
===== Ozone in the Martian Atmosphere ===== Mars has traces of ozone (including a seasonal ozone layer over the south pole in winter) and oxygen in its atmosphere both byproducts of life on Earth but explained by photochemistry on Mars. Mariner 7 detected ozone in 1971 and in 1976 by the Viking biological experiments. Significant levels of oxygen were detected in Gale Crater by Curiosity Rover in 2019 with seasonal variability that has not fully been explained. Studies indicate that the Martian atmosphere was once oxygen-rich. Today they are no longer considered valid biosignatures and are proposed to be the result of photodissociation of carbon dioxide. ===== Methane in the Martian Atmosphere ===== Martian methane is an area of ongoing research. With life being the strongest source of methane on Earth, continued observation of such a disequilibrium could be a viable biosignature. Current photochemical models cannot explain the reported rapid variations in space and time. Neither its fast appearance nor disappearance have been explained. Because of its tendency to be destroyed in the atmosphere by photochemistry, excess methane could indicate that there must be an active source. Since 2004 there have been several detection claims of methane in the Mars


id: biosignature-20260505-4
file: data/en.wikipedia.org/wiki/Biosignature-4.md
category: reference
title: Biosignature
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biosignature
date_saved: 2026-05-05T07:15:15.960639+00:00
instance: kb-cron
parent: biosignature-20260505-0
summary:
===== ExoMars Orbiter ===== The 2016 ExoMars Trace Gas Orbiter (TGO) is a Mars telecommunications orbiter and atmospheric gas analyzer mission. It delivered the Schiaparelli EDM lander and then began to settle into its science orbit to map the sources of methane on Mars and other gases, and in doing so, will help select the landing site for the Rosalind Franklin rover to be launched in 2028. The primary objective of the Rosalind Franklin rover mission is the search for biosignatures on the surface and subsurface by using a drill able to collect samples down to a depth of 2 metres (6.6 ft), away from the destructive radiation that bathes the surface. ===== Mars 2020 ===== The Mars 2020 rover, which launched in 2020, is intended to investigate an astrobiologically relevant ancient environment on Mars, investigate its surface geological processes and history, including the assessment of its past habitability, the possibility of past life on Mars, and potential for preservation of biosignatures within accessible geological materials. In addition, it will cache the most interesting samples for possible future transport to Earth. In 2024, Perseverance found a rock, called Cheyava Falls, during its exploration of the Jezero Crater. The rover's instruments


id: biosignature-20260505-5
file: data/en.wikipedia.org/wiki/Biosignature-5.md
category: reference
title: Biosignature
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Biosignature
date_saved: 2026-05-05T07:15:15.960639+00:00
instance: kb-cron
parent: biosignature-20260505-0
summary:
Voyager 1 (1979): The first close-up photos of Europa are taken. Scientists propose that a subsurface ocean could cause the tectonic-like marks on the surface. Galileo (1997): The magnetometer aboard this probe detected a subtle change in the magnetic field near Europa. This was later interpreted as a disruption in the expected magnetic field due to the current induction in a conducting layer on Europa. The composition of this conducting layer is consistent with a salty subsurface ocean. Hubble Space Telescope (2012): An image was taken of Europa which showed evidence for a plume of water vapor coming off the surface. The Europa Clipper probe includes instruments to help confirm the existence and composition of a subsurface ocean and thick icy layer. In addition, the instruments will be used to map and study surface features that may indicate tectonic activity due to a subsurface ocean. ===== Dragonfly ===== NASA's Dragonfly lander/aircraft concept is proposed to launch in 2028 and would seek evidence of biosignatures on the organic-rich surface and atmosphere of Titan, as well as study its possible prebiotic primordial soup. Titan is the largest moon of Saturn and is widely believed to have a large subsurface ocean consisting of


id: catabiosis-20260505-0
file: data/en.wikipedia.org/wiki/Catabiosis-0.md
category: reference
title: Catabiosis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Catabiosis
date_saved: 2026-05-05T07:15:17.204749+00:00
instance: kb-cron
parent: catabiosis-20260505-0
summary:
Catabiosis is the process of growing older, aging and physical degradation. The word comes from Greek "kata"—down, against, reverse and "biosis"—way of life and is generally used to describe senescence and degeneration in living organisms and biophysics of aging in general. One of the popular catabiotic theories is the entropy theory of aging, where aging is characterized by thermodynamically favourable increase in structural disorder. Living organisms are open systems that take free energy from the environment and offload their entropy as waste. However, basic components of living systems—DNA, proteins, lipids and sugars—tend towards the state of maximum entropy while continuously accumulating damages causing catabiosis of the living structure. Catabiotic force on the contrary is the influence exerted by living structures on adjoining cells, by which the latter are developed in harmony with the primary structures. == References == == External links == Onpedia definition of catabiosis Catabiotic force Dictionary.com - Catabiosis


id: chemotroph-20260505-0
file: data/en.wikipedia.org/wiki/Chemotroph-0.md
category: reference
title: Chemotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Chemotroph
date_saved: 2026-05-05T07:15:18.454829+00:00
instance: kb-cron
parent: chemotroph-20260505-0
summary:
A chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic (chemoorganotrophs) or inorganic (chemolithotrophs). The chemotroph designation is in contrast to phototrophs, which use photons. Chemotrophs can be either autotrophic or heterotrophic. Chemotrophs can be found in areas where electron donors are present in high concentration, for instance around hydrothermal vents. Some examples of chemotrophic organisms include iron-oxiding bacteria and methanogenic archaea. == Chemoautotroph == Chemoautotrophs are autotrophic organisms that can rely on chemosynthesis, i.e. deriving biological energy from chemical reactions of environmental inorganic substrates and synthesizing all necessary organic compounds from carbon dioxide. Chemoautotrophs can use inorganic energy sources such as hydrogen sulfide, elemental sulfur, ferrous iron, molecular hydrogen, and ammonia or organic sources to produce energy. Most chemoautotrophs are prokaryotic extremophiles, bacteria, or archaea that live in otherwise hostile environments (such as deep sea vents) and are the primary producers in such ecosystems. Chemoautotrophs generally fall into several groups: methanogens, sulfur oxidizers and reducers, nitrifiers, anammox bacteria, and thermoacidophiles. An example of one of these prokaryotes would be Sulfolobus. Chemolithotrophic growth can be very fast, such as Hydrogenovibrio crunogenus with a doubling time around one hour.


id: eukaryote-20260505-0
file: data/en.wikipedia.org/wiki/Eukaryote-0.md
category: reference
title: Eukaryote
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Eukaryote
date_saved: 2026-05-05T07:15:19.756158+00:00
instance: kb-cron
parent: eukaryote-20260505-0
summary:
The eukaryotes () are the domain of Eukaryota or Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of life forms alongside the two groups of prokaryotes: the Bacteria and the Archaea. Eukaryotes represent a small minority of the number of organisms, but given their generally much larger size, their collective global biomass is much larger than that of prokaryotes. The eukaryotes emerged within the archaeal phylum Promethearchaeota. Ignoring mitochondrial DNA (which is bacterial rather than archaeal), this would imply only two domains of life, Bacteria and Archaea, with eukaryotes incorporated among the Archaea. Eukaryotes first emerged during the Paleoproterozoic, likely as flagellated cells. The leading evolutionary theory is they were created by symbiogenesis between an anaerobic Promethearchaeota archaeon and an aerobic proteobacterium, which formed the mitochondria. A second episode of symbiogenesis with a cyanobacterium created the plants, with chloroplasts. Eukaryotic cells contain membrane-bound organelles such as the nucleus, the endoplasmic reticulum, and the Golgi apparatus. Eukaryotes may be either unicellular or multicellular. In comparison, prokaryotes are typically unicellular. Unicellular eukaryotes are sometimes called protists. Eukaryotes can reproduce both asexually through mitosis and sexually through


id: eukaryote-20260505-1
file: data/en.wikipedia.org/wiki/Eukaryote-1.md
category: reference
title: Eukaryote
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Eukaryote
date_saved: 2026-05-05T07:15:19.756158+00:00
instance: kb-cron
parent: eukaryote-20260505-0
summary:
Plants and various groups of algae have plastids as well as mitochondria. Plastids, like mitochondria, have their own DNA and are developed from endosymbionts, in this case cyanobacteria. They usually take the form of chloroplasts which, like cyanobacteria, contain chlorophyll and produce organic compounds (such as glucose) through photosynthesis. Others are involved in storing food. Although plastids probably had a single origin, not all plastid-containing groups are closely related. Instead, some eukaryotes have obtained them from other eukaryotes through secondary endosymbiosis or ingestion. The capture and sequestering of photosynthetic cells and chloroplasts, kleptoplasty, occurs in many types of modern eukaryotic organisms. === Cytoskeletal structures === The cytoskeleton provides stiffening structure and points of attachment for motor structures that enable the cell to move, change shape, or transport materials. The motor structures are microfilaments of actin and actin-binding proteins. These include α-actinin, fimbrin, and filamin in submembranous cortical layers and bundles. Motor proteins of microtubules, dynein and kinesin, and myosin of actin filaments, make the network dynamic. Many eukaryotes have long slender motile cytoplasmic projections, called flagella, or multiple shorter structures called cilia. These organelles are variously involved in movement, feeding, and sensation. They are composed mainly of tubulin, and are


id: eukaryote-20260505-2
file: data/en.wikipedia.org/wiki/Eukaryote-2.md
category: reference
title: Eukaryote
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Eukaryote
date_saved: 2026-05-05T07:15:19.756158+00:00
instance: kb-cron
parent: eukaryote-20260505-0
summary:
=== Phylogeny === By the early 21st century, a rough consensus started to emerge from phylogenomic studies. The majority of eukaryotes can be placed in one of two large clades dubbed Amorphea (similar in composition to the unikont hypothesis) and the Diphoda (formerly bikonts), which includes plants and most algal lineages. A third major grouping, the Excavata, has been abandoned as a formal group as it was found to be paraphyletic. The proposed phylogeny below includes two groups of excavates (Discoba and Metamonada), and incorporates the 2021 proposal that picozoans are close relatives of rhodophytes. The Provora are a group of microbial predators discovered in 2022. TSAR is a possible clade that would contain Telonemia and the SAR supergroup. One view of the great kingdoms and their stem groups. The Metamonada are hard to place, being sister possibly to Discoba or to Malawimonadida or being a paraphyletic group external to all other eukaryotes. Eukaryotes are thought to have emerged within the archaeal phylum Promethearchaeota. === Origin of eukaryotes === The origin of the eukaryotic cell, or eukaryogenesis, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms. The last eukaryotic common


id: facilitation-cascade-20260505-0
file: data/en.wikipedia.org/wiki/Facilitation_cascade-0.md
category: reference
title: Facilitation cascade
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Facilitation_cascade
date_saved: 2026-05-05T07:15:21.359452+00:00
instance: kb-cron
parent: facilitation-cascade-20260505-0
summary:
A facilitation cascade is a sequence of ecological interactions that occur when a species benefits a second species that in turn has a positive effect on a third species. These facilitative interactions can take the form of amelioration of environmental stress and/or provision of refuge from predation. Autogenic ecosystem engineering species, structural species, habitat-forming species, and foundation species are associated with the most commonly recognized examples of facilitation cascades, sometimes referred to as a habitat cascades. Facilitation generally is a much broader concept that includes all forms of positive interactions including pollination, seed dispersal, and co-evolved commensalism and mutualistic relationships, such as between cnidarian hosts and Symbiodinium in corals, and between algae and fungi in lichens. As such, facilitation cascades are widespread through all of the earth's major biomes with consistently positive effects on the abundance and biodiversity of associated organisms. == Overview == Facilitation cascades occur when prevalent foundation species, or less abundant but ecologically important keystone species, are involved in a hierarchy of positive interactions and consist of a primary facilitator which positively affects one or more secondary facilitators which support a suite of beneficiary species. Facilitation cascades at a minimum have a primary and secondary facilitator, although


id: facilitation-cascade-20260505-1
file: data/en.wikipedia.org/wiki/Facilitation_cascade-1.md
category: reference
title: Facilitation cascade
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Facilitation_cascade
date_saved: 2026-05-05T07:15:21.359452+00:00
instance: kb-cron
parent: facilitation-cascade-20260505-0
summary:
=== Transitional (intertidal) === On the cobblestone beaches of New England, cordgrasse ameliorates physical stress for the establishment of ribbed mussels which further facilitating increased diversity within the intertidal ecosystem as secondary foundation species. This is the interaction from which the facilitation cascade concept was formed. This complex habitat has also shown how facilitation cascades can increases invasibility because non-native crabs live on and among ribbed mussels, providing a mechanisms to explain positive relationships between native diversity and invasion success, and the co-existence of native and invasive species through differential use of microhabitats associated with the cascade. In salt marshes, the same species of cordgrass and mussels have also been shown to increase biodiversity, multifunctionality, and resilience to disturbance. Oyster reefs stabilize the intertidal environment by reducing sediment erosion. This enhances growth of marsh grasses which act as secondary foundation species, facilitating invertebrates including bivalves, insects and birds. The places with oyster reefs and intertidal marshes have been observed to support a higher biodiversity and abundance of inhabitants compared to sites inhabited by only one of those foundation species. Mangrove forests along the coast of Australia trap drifting seaweed among their pneumatophores, which this seaweed supports many mollusks through habitat


id: facilitation-cascade-20260505-2
file: data/en.wikipedia.org/wiki/Facilitation_cascade-2.md
category: reference
title: Facilitation cascade
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Facilitation_cascade
date_saved: 2026-05-05T07:15:21.359452+00:00
instance: kb-cron
parent: facilitation-cascade-20260505-0
summary:
=== Temporal variation === The strength of facilitation cascades can also vary across temporal scales. Spatial scale can be influenced by how rapidly a foundation species grows or reproduces, as well as how long the effect of facilitation takes to impact other species within the system. This can be due to the time necessary for a foundation species to reach a minimum individual or patch size to create a facilitative effect for the system, lags in the demographic response in the beneficiary species to the positive effects of a facilitator, or seasonality or some other temporal variability in the stress that the facilitator ameliorates. Phenological matching or mismatching of life cycles may also influence the co-occurrence of participants in a facilitation cascade and therefore the strength of their interaction. For example, hatching of insects that coincides with flowering of the plants they pollinate which are in turn used as habitat for other species later in that year. === Dispersal and movement === Movement of organisms can mediate the occurrence and importance of facilitation cascades in three ways. First, movement of a facilitative species to a location with another facilitative species can bring together the components for a facilitation cascade. For


id: facilitation-cascade-20260505-3
file: data/en.wikipedia.org/wiki/Facilitation_cascade-3.md
category: reference
title: Facilitation cascade
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Facilitation_cascade
date_saved: 2026-05-05T07:15:21.359452+00:00
instance: kb-cron
parent: facilitation-cascade-20260505-0
summary:
==== Pollution ==== The introduction of harmful or toxic substances into the environment is a threat to facilitation cascades. Nutrient pollution may initially appear to benefit facilitation cascades by stimulating growth of habitat forming species, but ultimately negative effects associated with excess biomass, such as physically smothering and biogeochemical stressors including oxygen depletion and sulfide toxicity, can overwhelm the facilitation cascade. For example, excessive amounts of nutrients can stimulate prolific growth of secondary foundation species such as seaweed in otherwise oligotrophic seagrass systems, resulting in altered competitive hierarchies where the seaweed outcompetes the seagrass. In other instances, eutrophication can lead to an outright replacement of habitat dominants, such as when macroalgae replaces corals on reefs, leading to a change or loss in components of a facilitation cascade and there a shift in the broader community. ==== Disease ==== Disease prevalence and severity are predicted to increase in response to global changes, though its impacts on facilitation cascades remain relatively understudied. High endemic biodiversity, such as that favored by a facilitation cascade, generally decreases the risk of pathogen transmission. However, disease outbreaks that impact a facilitator can reduce its density or alter its phenotype, thereby reducing habitat complexity which dampens its


id: facultative-20260505-0
file: data/en.wikipedia.org/wiki/Facultative-0.md
category: reference
title: Facultative
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Facultative
date_saved: 2026-05-05T07:15:22.612139+00:00
instance: kb-cron
parent: facultative-20260505-0
summary:
Facultative means "optional" or "discretionary" (antonym obligate), and is used mainly in biology. It is seen in topics including: Facultative anaerobe, an organism that can use oxygen but also has anaerobic methods of energy production. Facultative biotroph, an organism, often a fungus, that can live as a saprotroph but also form mutualisms with other organisms at different times of its life cycle. Facultative biped, an animal that is capable of walking or running on two legs as well as walking or running on four limbs or more, as appropriate Facultative carnivore, a carnivore that does not depend solely on animal flesh for food but also can subsist on non-animal food. Compare this with the term omnivore Facultative heterochromatin, tightly packed but non-repetitive DNA in the form of Heterochromatin, but which can lose its condensed structure and become transcriptionally active Facultative lagoon, a type of stabilization pond used in biological treatment of industrial and domestic wastewater Facultative necrophage, an animal that feeds on carrion but retains the traits needed to find and consume other food sources Facultative parasite, a parasite that can complete its life cycle without depending on a host Facultative photoperiodic plant, a plant that will eventually flower regardless


id: flux-biology-20260505-0
file: data/en.wikipedia.org/wiki/Flux_(biology)-0.md
category: reference
title: Flux (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Flux_(biology)
date_saved: 2026-05-05T07:15:23.812857+00:00
instance: kb-cron
parent: flux-biology-20260505-0
summary:
In general, flux in biology relates to movement of a substance between compartments. There are several cases where the concept of flux is important. The movement of molecules across a membrane: in this case, flux is defined by the rate of diffusion or transport of a substance across a permeable membrane. Except in the case of active transport, net flux is directly proportional to the concentration difference across the membrane, the surface area of the membrane, and the membrane permeability constant. In ecology, flux is often considered at the ecosystem level – for instance, accurate determination of carbon fluxes using techniques like eddy covariance (at a regional and global level) is essential for modeling the causes and consequences of global warming. Metabolic flux refers to the rate of flow of metabolites through a biochemical network, along a linear metabolic pathway, or through a single enzyme. A calculation may also be made of carbon flux or flux of other elemental components of biomolecules (e.g. nitrogen). The general unit of flux is chemical mass /time (e.g., micromole/minute; mg/kg/minute). Flux rates are dependent on a number of factors, including: enzyme concentration; the concentration of precursor, product, and intermediate metabolites; post-translational modification of enzymes;


id: gracility-20260505-0
file: data/en.wikipedia.org/wiki/Gracility-0.md
category: reference
title: Gracility
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Gracility
date_saved: 2026-05-05T07:15:26.372103+00:00
instance: kb-cron
parent: gracility-20260505-0
summary:
Gracility is slenderness, the condition of being gracile, which means slender. It derives from the Latin adjective gracilis (masculine or feminine), or gracile (neuter), which in either form means slender, and when transferred for example to discourse takes the sense of "without ornament", "simple" or various similar connotations. In Glossary of Botanic Terms, B. D. Jackson speaks dismissively of an entry in earlier dictionary of A. A. Crozier as follows: "Gracilis (Lat.), slender. Crozier has the needless word 'gracile'". However, his objection would be hard to sustain in current usage; apart from the fact that gracile is a natural and convenient term, it is hardly a neologism. The Shorter Oxford English Dictionary gives the source date for that usage as 1623 and indicates the word is misused (through association with grace) for "gracefully slender". This misuse is unfortunate at least, because the terms gracile and grace are unrelated: the etymological root of grace is the Latin word gratia from gratus, meaning 'pleasing', and has nothing to do with slenderness or thinness. == In biology == In biology, the term is in common use, whether as English or Latin: The term gracile and its opposite, robust—occur in discussion of the morphology


id: haplotype-block-20260505-0
file: data/en.wikipedia.org/wiki/Haplotype_block-0.md
category: reference
title: Haplotype block
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Haplotype_block
date_saved: 2026-05-05T07:15:27.632738+00:00
instance: kb-cron
parent: haplotype-block-20260505-0
summary:
In genetics, a haplotype block is a region of an organism's genome in which there is little evidence of a history of genetic recombination, and which contain only a small number of distinct haplotypes. According to the haplotype-block model, such blocks should show high levels of linkage disequilibrium and be separated from one another by numerous recombination events. The boundaries of haplotype blocks cannot be directly observed; they must instead be inferred indirectly through the use of algorithms. However, some evidence suggests that different algorithms for identifying haplotype blocks give very different results when used on the same data, though another study suggests that their results are generally consistent. The National Institutes of Health funded the HapMap project to catalog haplotype blocks throughout the human genome. == Definition == There are two main ways that the term "haplotype block" is defined: one based on whether a given genomic sequence displays higher linkage disequilibrium than a predetermined threshold, and one based on whether the sequence consists of a minimum number of single nucleotide polymorphisms (SNPs) that explain a majority of the common haplotypes in the sequence (or a lower-than-usual number of unique haplotypes). In 2001, Patil et al. proposed the following


id: heterotroph-20260505-0
file: data/en.wikipedia.org/wiki/Heterotroph-0.md
category: reference
title: Heterotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Heterotroph
date_saved: 2026-05-05T07:15:28.864372+00:00
instance: kb-cron
parent: heterotroph-20260505-0
summary:
A heterotroph (; from Ancient Greek ἕτερος (héteros), meaning "other", and τροφή (trophḗ), meaning "nourishment") is an organism that cannot produce its own food, instead taking nutrition from other sources of organic carbon, mainly matter from other organisms. In the food chain, heterotrophs are primary, secondary and tertiary consumers, but not producers. Living organisms that are heterotrophic include most animals, all fungi, some bacteria and protists, and many parasitic plants. The term heterotroph arose in microbiology in 1946 as part of a classification of microorganisms based on their type of nutrition. The term is now used in many fields, such as ecology, in describing the food chain. Heterotrophs occupy the second and third trophic levels of the food chain while autotrophs occupy the first trophic level. Heterotrophs may be subdivided according to their energy source. If the heterotroph uses chemical energy, it is a chemoheterotroph (e.g., humans and mushrooms). If it uses light for energy, then it is a photoheterotroph (e.g., haloquadratum walsbyi and green non-sulfur bacteria). Heterotrophs represent one of the two mechanisms of nutrition (trophic levels), the other being autotrophs (auto = self, troph = nutrition). Autotrophs use energy from sunlight (photoautotrophs) or oxidation of inorganic compounds (lithoautotrophs)


id: heterotroph-20260505-1
file: data/en.wikipedia.org/wiki/Heterotroph-1.md
category: reference
title: Heterotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Heterotroph
date_saved: 2026-05-05T07:15:28.864372+00:00
instance: kb-cron
parent: heterotroph-20260505-0
summary:
== Origin and diversification == The chemical origin of life hypothesis suggests that life originated in a prebiotic soup with heterotrophs. The summary of this theory is as follows: early Earth had a highly reducing atmosphere and energy sources such as electrical energy in the form of lightning, which resulted in reactions that formed simple organic compounds, which further reacted to form more complex compounds and eventually resulted in life. Alternative theories of an autotrophic origin of life contradict this theory. The theory of a chemical origin of life beginning with heterotrophic life was first proposed in 1924 by Alexander Ivanovich Oparin, and eventually published "The Origin of Life." It was independently proposed for the first time in English in 1929 by John Burdon Sanderson Haldane. While these authors agreed on the gasses present and the progression of events to a point, Oparin championed a progressive complexity of organic matter prior to the formation of cells, while Haldane had more considerations about the concept of genes as units of heredity and the possibility of light playing a role in chemical synthesis (autotrophy). Evidence grew to support this theory in 1953, when Stanley Miller conducted an experiment in which he added


id: heterotroph-20260505-2
file: data/en.wikipedia.org/wiki/Heterotroph-2.md
category: reference
title: Heterotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Heterotroph
date_saved: 2026-05-05T07:15:28.864372+00:00
instance: kb-cron
parent: heterotroph-20260505-0
summary:
Many heterotrophs are chemoorganoheterotrophs that use organic carbon (e.g. glucose) as their carbon source, and organic chemicals (e.g. carbohydrates, lipids, proteins) as their electron sources. Heterotrophs function as consumers in food chain: they obtain these nutrients from saprotrophic, parasitic, or holozoic nutrients. They break down complex organic compounds (e.g., carbohydrates, fats, and proteins) produced by autotrophs into simpler compounds (e.g., carbohydrates into glucose, fats into fatty acids and glycerol, and proteins into amino acids). They release the chemical energy of nutrient molecules by oxidizing carbon and hydrogen atoms from carbohydrates, lipids, and proteins to carbon dioxide and water, respectively. They can catabolize organic compounds by respiration, fermentation, or both. Fermenting heterotrophs are either facultative or obligate anaerobes that carry out fermentation in low oxygen environments, in which the production of ATP is commonly coupled with substrate-level phosphorylation and the production of end products (e.g. alcohol, CO2, sulfide). These products can then serve as the substrates for other bacteria in the anaerobic digestion, and be converted into CO2 and CH4, which is an important step for the carbon cycle for removing organic fermentation products from anaerobic environments. Heterotrophs can undergo respiration, in which ATP production is coupled with oxidative phosphorylation. This


id: heterotroph-20260505-3
file: data/en.wikipedia.org/wiki/Heterotroph-3.md
category: reference
title: Heterotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Heterotroph
date_saved: 2026-05-05T07:15:28.864372+00:00
instance: kb-cron
parent: heterotroph-20260505-0
summary:
== Impacts on Biogeochemical Cycles == Heterotrophs, organisms that obtain energy and carbon by consuming organic matter, are vital parts of Earth's biogeochemical cycles particularly in the carbon, nitrogen, and sulfur cycles. Their metabolic activities impact the processing and cycling of elements through ecosystems and the biosphere. Heterotrophs are key players in the carbon cycle, acting as both consumers and decomposers. They release carbon dioxide (CO2) into the atmosphere through respiration, contributing to a large portion of carbon dioxide emissions. This process makes carbon available for autotrophs, who can fix carbon through photosynthesis or chemosynthesis. This circulation supports the continuous cycling of carbon between organic and inorganic forms. Heterotrophic organisms contribute to key processes in the nitrogen cycle like ammonification, the conversion of organic nitrogen to ammonia, and denitrification, the reduction of nitrate and the release of nitrogen gas to the atmosphere. Heterotrophic microorganisms are essential in the mineralization of organic compounds containing nitrogen. Through deamination, they convert organic nitrogen to ammonium (NH4+), which can be further oxidized by lithotrophs into forms available to plants. Similarly, desulfurylation by heterotrophs transforms organic sulfur into hydrogen sulfide (H2S), which is then oxidized by lithotrophs and phototrophs, contributing to the sulfur cycle. The


id: hindgut-fermentation-20260505-0
file: data/en.wikipedia.org/wiki/Hindgut_fermentation-0.md
category: reference
title: Hindgut fermentation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hindgut_fermentation
date_saved: 2026-05-05T07:15:30.125848+00:00
instance: kb-cron
parent: hindgut-fermentation-20260505-0
summary:
Hindgut fermentation is a digestive process seen in monogastric herbivores (animals with a simple, single-chambered stomach). Cellulose is digested with the aid of symbiotic microbes including bacteria, archaea, and eukaryotes. The microbial fermentation occurs in the digestive organs that follow the small intestine: the cecum and large intestine. Examples of hindgut fermenters include proboscideans and large odd-toed ungulates such as horses and rhinos, as well as small animals such as rodents, rabbits and koalas. In contrast, foregut fermentation is the form of cellulose digestion seen in ruminants such as cattle which have a four-chambered stomach, as well as in sloths, macropodids, some monkeys, and one bird, the hoatzin. == Cecum == Hindgut fermenters generally have a cecum and large intestine that are much larger and more complex than those of a foregut fermenter. Research on small cecum fermenters such as flying squirrels, rabbits and lemurs has revealed these mammals to have a GI tract about 10-13 times the length of their body. This is due to the high intake of fiber and other hard to digest compounds that are characteristic to the diet of monogastric herbivores. Easily digestible food is processed in the gastrointestinal tract & expelled as regular feces.


id: homeostasis-20260505-0
file: data/en.wikipedia.org/wiki/Homeostasis-0.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
In biology, homeostasis (British also homoeostasis; HOH-mee-ə-STAY-sis) is the state of steady internal physical and chemical conditions maintained by living organisms. This is the condition of optimal functioning for the organism and includes many variables, such as body temperature and fluid balance, being kept within certain pre-set limits (homeostatic range). Other variables include the pH of extracellular fluid, the concentrations of sodium, potassium, and calcium ions, as well as the blood sugar level, and these need to be regulated despite changes in the environment, diet, or level of activity. Each of these variables is controlled by one or more regulators or homeostatic mechanisms, which together maintain life. Homeostasis is brought about by a natural resistance to change when already in its optimal conditions, and equilibrium is maintained by many regulatory mechanisms; it is thought to be the central motivation for all organic action. All homeostatic control mechanisms have at least three interdependent components for the variable being regulated: a receptor, a control center, and an effector. The receptor is the sensing component that monitors and responds to changes in the environment, either external or internal. Receptors include thermoreceptors and mechanoreceptors. Control centers include the respiratory center and the renin-angiotensin system.


id: homeostasis-20260505-1
file: data/en.wikipedia.org/wiki/Homeostasis-1.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
If an entity is homeostatically controlled it does not imply that its value is necessarily absolutely steady in health. Core body temperature is, for instance, regulated by a homeostatic mechanism with temperature sensors in, amongst others, the hypothalamus of the brain. However, the set point of the regulator is regularly reset. For instance, core body temperature in humans varies during the course of the day (i.e. has a circadian rhythm), with the lowest temperatures occurring at night, and the highest in the afternoons. Other normal temperature variations include those related to the menstrual cycle. The temperature regulator's set point is reset during infections to produce a fever. Organisms are capable of adjusting somewhat to varied conditions such as temperature changes or oxygen levels at altitude, by a process of acclimatisation. Homeostasis does not govern every activity in the body. For instance, the signal (be it via neurons or hormones) from the sensor to the effector is, of necessity, highly variable in order to convey information about the direction and magnitude of the error detected by the sensor. Similarly, the effector's response needs to be highly adjustable to reverse the error – in fact it should be very nearly in proportion


id: homeostasis-20260505-2
file: data/en.wikipedia.org/wiki/Homeostasis-2.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
Blood sugar levels are regulated within fairly narrow limits. In mammals, the primary sensors for this are the beta cells of the pancreatic islets. The beta cells respond to a rise in the blood sugar level by secreting insulin into the blood and simultaneously inhibiting their neighboring alpha cells from secreting glucagon into the blood. This combination (high blood insulin levels and low glucagon levels) act on effector tissues, the chief of which is the liver, fat cells, and muscle cells. The liver is inhibited from producing glucose, taking it up instead, and converting it to glycogen and triglycerides. The glycogen is stored in the liver, but the triglycerides are secreted into the blood as very low-density lipoprotein (VLDL) particles which are taken up by adipose tissue, there to be stored as fats. The fat cells take up glucose through special glucose transporters (GLUT4), whose numbers in the cell wall are increased as a direct effect of insulin acting on these cells. The glucose that enters the fat cells in this manner is converted into triglycerides (via the same metabolic pathways as are used by the liver) and then stored in those fat cells together with the VLDL-derived triglycerides that


id: homeostasis-20260505-3
file: data/en.wikipedia.org/wiki/Homeostasis-3.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
Changes in the levels of oxygen, carbon dioxide, and plasma pH are sent to the respiratory center, in the brainstem where they are regulated. The partial pressure of oxygen and carbon dioxide in the arterial blood is monitored by the peripheral chemoreceptors (PNS) in the carotid artery and aortic arch. A change in the partial pressure of carbon dioxide is detected as altered pH in the cerebrospinal fluid by central chemoreceptors (CNS) in the medulla oblongata of the brainstem. Information from these sets of sensors is sent to the respiratory center which activates the effector organs – the diaphragm and other muscles of respiration. An increased level of carbon dioxide in the blood, or a decreased level of oxygen, will result in a deeper breathing pattern and increased respiratory rate to bring the blood gases back to equilibrium. Too little carbon dioxide, and, to a lesser extent, too much oxygen in the blood can temporarily halt breathing, a condition known as apnea, which freedivers use to prolong the time they can stay underwater. The partial pressure of carbon dioxide is more of a deciding factor in the monitoring of pH. However, at high altitude (above 2500 m) the monitoring of


id: homeostasis-20260505-4
file: data/en.wikipedia.org/wiki/Homeostasis-4.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
The plasma ionized calcium (Ca2+) concentration is very tightly controlled by a pair of homeostatic mechanisms. The sensor for the first one is situated in the parathyroid glands, where the chief cells sense the Ca2+ level by means of specialized calcium receptors in their membranes. The sensors for the second are the parafollicular cells in the thyroid gland. The parathyroid chief cells secrete parathyroid hormone (PTH) in response to a fall in the plasma ionized calcium level; the parafollicular cells of the thyroid gland secrete calcitonin in response to a rise in the plasma ionized calcium level. The effector organs of the first homeostatic mechanism are the bones, the kidney, and, via a hormone released into the blood by the kidney in response to high PTH levels in the blood, the duodenum and jejunum. Parathyroid hormone (in high concentrations in the blood) causes bone resorption, releasing calcium into the plasma. This is a very rapid action which can correct a threatening hypocalcemia within minutes. High PTH concentrations cause the excretion of phosphate ions via the urine. Since phosphates combine with calcium ions to form insoluble salts (see also bone mineral), a decrease in the level of phosphates in the blood,


id: homeostasis-20260505-5
file: data/en.wikipedia.org/wiki/Homeostasis-5.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
=== Sodium concentration === The homeostatic mechanism which controls the plasma sodium concentration is rather more complex than most of the other homeostatic mechanisms described on this page. The sensor is situated in the juxtaglomerular apparatus of kidneys, which senses the plasma sodium concentration in a surprisingly indirect manner. Instead of measuring it directly in the blood flowing past the juxtaglomerular cells, these cells respond to the sodium concentration in the renal tubular fluid after it has already undergone a certain amount of modification in the proximal convoluted tubule and loop of Henle. These cells also respond to rate of blood flow through the juxtaglomerular apparatus, which, under normal circumstances, is directly proportional to the arterial blood pressure, making this tissue an ancillary arterial blood pressure sensor. In response to a lowering of the plasma sodium concentration, or to a fall in the arterial blood pressure, the juxtaglomerular cells release renin into the blood. Renin is an enzyme which cleaves a decapeptide (a short protein chain, 10 amino acids long) from a plasma α-2-globulin called angiotensinogen. This decapeptide is known as angiotensin I. It has no known biological activity. However, when the blood circulates through the lungs a pulmonary capillary


id: homeostasis-20260505-6
file: data/en.wikipedia.org/wiki/Homeostasis-6.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
The total amount of water in the body needs to be kept in balance. Fluid balance involves keeping the fluid volume stabilized, and also keeping the levels of electrolytes in the extracellular fluid stable. Fluid balance is maintained by the process of osmoregulation and by behavior. Osmotic pressure is detected by osmoreceptors in the median preoptic nucleus in the hypothalamus. Measurement of the plasma osmolality to give an indication of the water content of the body, relies on the fact that water losses from the body, (through unavoidable water loss through the skin which is not entirely waterproof and therefore always slightly moist, water vapor in the exhaled air, sweating, vomiting, normal feces and especially diarrhea) are all hypotonic, meaning that they are less salty than the body fluids (compare, for instance, the taste of saliva with that of tears. The latter has almost the same salt content as the extracellular fluid, whereas the former is hypotonic with respect to the plasma. Saliva does not taste salty, whereas tears are decidedly salty). Nearly all normal and abnormal losses of body water therefore cause the extracellular fluid to become hypertonic. Conversely, excessive fluid intake dilutes the extracellular fluid causing the hypothalamus


id: homeostasis-20260505-7
file: data/en.wikipedia.org/wiki/Homeostasis-7.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
=== Neurotransmission === Inhibitory neurons in the central nervous system play a homeostatic role in the balance of neuronal activity between excitation and inhibition. Inhibitory neurons using GABA, make compensating changes in the neuronal networks preventing runaway levels of excitation. An imbalance between excitation and inhibition is seen to be implicated in a number of neuropsychiatric disorders. === Neuroendocrine system === The neuroendocrine system is the mechanism by which the hypothalamus maintains homeostasis, regulating metabolism, reproduction, eating and drinking behaviour, energy utilization, osmolarity and blood pressure. The regulation of metabolism, is carried out by hypothalamic interconnections to other glands. Three endocrine glands of the hypothalamic–pituitary–gonadal axis (HPG axis) often work together and have important regulatory functions. Two other regulatory endocrine axes are the hypothalamic–pituitary–adrenal axis (HPA axis) and the hypothalamic–pituitary–thyroid axis (HPT axis). The liver also has many regulatory functions of the metabolism. An important function is the production and control of bile acids. Too much bile acid can be toxic to cells and its synthesis can be inhibited by activation of FXR a nuclear receptor. === Gene regulation === At the cellular level, homeostasis is carried out by several mechanisms including transcriptional regulation that can alter the activity of


id: homeostasis-20260505-8
file: data/en.wikipedia.org/wiki/Homeostasis-8.md
category: reference
title: Homeostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Homeostasis
date_saved: 2026-05-05T07:15:31.436253+00:00
instance: kb-cron
parent: homeostasis-20260505-0
summary:
== Biosphere == In the Gaia hypothesis, James Lovelock stated that the entire mass of living matter on Earth (or any planet with life) functions as a vast homeostatic superorganism that actively modifies its planetary environment to produce the environmental conditions necessary for its own survival. In this view, the entire planet maintains several homeostasis (the primary one being temperature homeostasis). Whether this sort of system is present on Earth is open to debate. However, some relatively simple homeostatic mechanisms are generally accepted. For example, it is sometimes claimed that when atmospheric carbon dioxide levels rise, certain plants may be able to grow better and thus act to remove more carbon dioxide from the atmosphere. However, warming has exacerbated droughts, making water the actual limiting factor on land. When sunlight is plentiful and the atmospheric temperature climbs, it has been claimed that the phytoplankton of the ocean surface waters, acting as global sunshine, and therefore heat sensors, may thrive and produce more dimethyl sulfide (DMS). The DMS molecules act as cloud condensation nuclei, which produce more clouds, and thus increase the atmospheric albedo, and this feeds back to lower the temperature of the atmosphere. However, rising sea temperature has stratified


id: hybrid-biology-20260505-0
file: data/en.wikipedia.org/wiki/Hybrid_(biology)-0.md
category: reference
title: Hybrid (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hybrid_(biology)
date_saved: 2026-05-05T07:15:32.895326+00:00
instance: kb-cron
parent: hybrid-biology-20260505-0
summary:
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different varieties, subspecies, species or genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera. Hybrids are not always intermediates between their parents such as in blending inheritance (a now discredited theory in modern genetics by particulate inheritance), but can show hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species must be for their offspring to be classified as a hybrid, since crosses between species within the same genera are often treated differently from crosses between more distantly related taxa. Species are reproductively isolated by strong barriers to hybridization, which include genetic and morphological differences, differing times of fertility, mating behaviors and cues, and physiological rejection of sperm cells or the developing embryo. Some act before fertilization


id: hybrid-biology-20260505-1
file: data/en.wikipedia.org/wiki/Hybrid_(biology)-1.md
category: reference
title: Hybrid (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hybrid_(biology)
date_saved: 2026-05-05T07:15:32.895326+00:00
instance: kb-cron
parent: hybrid-biology-20260505-0
summary:
=== Animal and plant breeding === From the point of view of animal and plant breeders, there are several kinds of hybrid formed from crosses within a species, such as between different breeds. Single cross hybrids result from the cross between two true-breeding organisms which produces an F1 hybrid (first filial generation). The cross between two different homozygous lines produces an F1 hybrid that is heterozygous; having two alleles, one contributed by each parent and typically one is dominant and the other recessive. Typically, the F1 generation is also phenotypically homogeneous, producing offspring that are all similar to each other. Double cross hybrids result from the cross between two different F1 hybrids (i.e., there are four unrelated grandparents). Three-way cross hybrids result from the cross between an F1 hybrid and an inbred line. Triple cross hybrids result from the crossing of two different three-way cross hybrids. Top cross (or "topcross") hybrids result from the crossing of a top quality or pure-bred male and a lower quality female, intended to improve the quality of the offspring, on average. Population hybrids result from the crossing of plants or animals in one population with those of another population. These include interspecific hybrids or


id: hybrid-biology-20260505-2
file: data/en.wikipedia.org/wiki/Hybrid_(biology)-2.md
category: reference
title: Hybrid (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hybrid_(biology)
date_saved: 2026-05-05T07:15:32.895326+00:00
instance: kb-cron
parent: hybrid-biology-20260505-0
summary:
A few animal species are the result of hybridization. The Lonicera fly is a natural hybrid. The American red wolf appears to be a hybrid of the gray wolf and the coyote, although its taxonomic status has been a subject of controversy. The European edible frog is a semi-permanent hybrid between pool frogs and marsh frogs; its population requires the continued presence of at least one of the parent species. Cave paintings indicate that the European bison is a natural hybrid of the aurochs and the steppe bison. Plant hybridization is more commonplace compared to animal hybridization. Many crop species are hybrids, including notably the polyploid wheats: some have four sets of chromosomes (tetraploid) or six (hexaploid), while other wheat species have (like most eukaryotic organisms) two sets (diploid), so hybridization events likely involved the doubling of chromosome sets, causing immediate genetic isolation. Hybridization may be important in speciation in some plant groups. However, homoploid hybrid speciation (not increasing the number of sets of chromosomes) may be rare: by 1997, only eight natural examples had been fully described. Experimental studies suggest that hybridization offers a rapid route to speciation, a prediction confirmed by the fact that early generation hybrids and


id: hybrid-biology-20260505-3
file: data/en.wikipedia.org/wiki/Hybrid_(biology)-3.md
category: reference
title: Hybrid (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hybrid_(biology)
date_saved: 2026-05-05T07:15:32.895326+00:00
instance: kb-cron
parent: hybrid-biology-20260505-0
summary:
In agriculture and animal husbandry, the Green Revolution's use of conventional hybridization increased yields by breeding high-yielding varieties. The replacement of locally indigenous breeds, compounded with unintentional cross-pollination and crossbreeding (genetic mixing), has reduced the gene pools of various wild and indigenous breeds resulting in the loss of genetic diversity. Since the indigenous breeds are often well-adapted to local extremes in climate and have immunity to local pathogens, this can be a significant genetic erosion of the gene pool for future breeding. Therefore, commercial plant geneticists strive to breed "widely adapted" cultivars to counteract this tendency. == Different taxa == === In animals === ==== Mammals ==== Familiar examples of equid hybrids are the mule, a cross between a female horse and a male donkey, and the hinny, a cross between a female donkey and a male horse. Pairs of complementary types like the mule and hinny are called reciprocal hybrids. Polar bears and brown bears are another case of a hybridizing species pairs, and introgression among non-sister species of bears appears to have shaped the Ursidae family tree. Among many other mammal crosses are hybrid camels, crosses between a bactrian camel and a dromedary. There are many examples of


id: hybrid-biology-20260505-4
file: data/en.wikipedia.org/wiki/Hybrid_(biology)-4.md
category: reference
title: Hybrid (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hybrid_(biology)
date_saved: 2026-05-05T07:15:32.895326+00:00
instance: kb-cron
parent: hybrid-biology-20260505-0
summary:
Plant species hybridize more readily than animal species, and the resulting hybrids are fertile more often. Many plant species are the result of hybridization, combined with polyploidy, which duplicates the chromosomes. Chromosome duplication allows orderly meiosis and so viable seed can be produced. Plant hybrids are generally given names that include an "×" (not in italics), such as Platanus × hispanica for the London plane, a natural hybrid of P. orientalis (oriental plane) and P. occidentalis (American sycamore). The parent's names may be kept in their entirety, as seen in Prunus persica × Prunus americana, with the female parent's name given first, or if not known, the parent's names given alphabetically. Plant species that are genetically compatible may not hybridize in nature for various reasons, including geographical isolation, differences in flowering period, or differences in pollinators. Species that are brought together by humans in gardens may hybridize naturally, or hybridization can be facilitated by human efforts, such as altered flowering period or artificial pollination. Hybrids are sometimes created by humans to produce improved plants that have some of the characteristics of each of the parent species. Much work is now being done with hybrids between crops and their wild relatives


id: hybrid-incompatibility-20260505-0
file: data/en.wikipedia.org/wiki/Hybrid_incompatibility-0.md
category: reference
title: Hybrid incompatibility
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Hybrid_incompatibility
date_saved: 2026-05-05T07:15:34.128889+00:00
instance: kb-cron
parent: hybrid-incompatibility-20260505-0
summary:
Hybrid incompatibility is a phenomenon in plants and animals, wherein offspring produced by the mating of two different species or populations have reduced viability and/or are less able to reproduce. Examples of hybrids include mules and ligers from the animal world, and subspecies of the Asian rice crop Oryza sativa from the plant world. Multiple models have been developed to explain this phenomenon. Recent research suggests that the source of this incompatibility is largely genetic, as combinations of genes and alleles prove lethal to the hybrid organism. Incompatibility is not solely influenced by genetics, however, and can be affected by environmental factors such as temperature. The genetic underpinnings of hybrid incompatibility may provide insight into factors responsible for evolutionary divergence between species. == Background == Hybrid incompatibility occurs when the offspring of two closely related species are not viable or suffer from infertility. Charles Darwin posited that hybrid incompatibility is not a product of natural selection, stating that the phenomenon is an outcome of the hybridizing species diverging, rather than something that is directly acted upon by selective pressures. The underlying causes of the incompatibility can be varied: earlier research focused on things like changes in ploidy in plants. More


id: individuation-20260505-0
file: data/en.wikipedia.org/wiki/Individuation-0.md
category: reference
title: Individuation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Individuation
date_saved: 2026-05-05T07:15:35.415660+00:00
instance: kb-cron
parent: individuation-20260505-0
summary:
The principle of individuation, or principium individuationis, describes the manner in which a thing is identified as distinct from other things. The concept appears in numerous fields and is encountered in works of Leibniz, Carl Jung, Gunther Anders, Gilbert Simondon, Bernard Stiegler, Friedrich Nietzsche, Arthur Schopenhauer, David Bohm, Henri Bergson, Gilles Deleuze, and Manuel DeLanda. == Usage == The word individuation occurs with different meanings and connotations in different fields. === In philosophy === Philosophically, "individuation" expresses the general idea of how a thing is identified as an individual thing that "is not something else". This includes how an individual person is held to be different from other elements in the world and how a person is distinct from other persons. By the seventeenth century, philosophers began to associate the question of individuation or what brings about individuality at any one time with the question of identity or what constitutes sameness at different points in time. === In Jungian psychology === In analytical psychology, individuation is the process by which the individual self develops out of an undifferentiated unconscious – seen as a developmental psychic process during which innate elements of personality, the components of the immature psyche, and the


id: individuation-20260505-1
file: data/en.wikipedia.org/wiki/Individuation-1.md
category: reference
title: Individuation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Individuation
date_saved: 2026-05-05T07:15:35.415660+00:00
instance: kb-cron
parent: individuation-20260505-0
summary:
According to Jungian psychology, individuation (German: Individuation) is a process of psychological integration. "In general, it is the process by which individual beings are formed and differentiated [from other human beings]; in particular, it is the development of the psychological individual as a being distinct from the general, collective psychology." Individuation is a process of transformation whereby the personal and collective unconscious are brought into consciousness (e.g., by means of dreams, active imagination, or free association) to be assimilated into the whole personality. It is a completely natural process that is necessary for the integration of the psyche. Individuation has a holistic healing effect on the person, both mentally and physically. In addition to Jung's theory of complexes, his theory of the individuation process forms conceptions of an unconscious filled with mythic images, a non-sexual libido, the general types of extraversion and introversion, the compensatory and prospective functions of dreams, and the synthetic and constructive approaches to fantasy formation and utilization. "The symbols of the individuation process . . . mark its stages like milestones, prominent among them for Jungians being the shadow, the wise old man . . . and lastly the anima in man and the animus in


id: individuation-20260505-2
file: data/en.wikipedia.org/wiki/Individuation-2.md
category: reference
title: Individuation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Individuation
date_saved: 2026-05-05T07:15:35.415660+00:00
instance: kb-cron
parent: individuation-20260505-0
summary:
== In collectivistic cultures == Research indicates that individuation is culturally mediated: in collectivist societies, expressions of individuation "take the lead" or "seek attention" rather than follow a singular independent pattern. Concepts like "integrative individuation" emphasize maintaining relational bonds rather than complete separation. Collectivist norms tend to discourage standing out, meaning individuation is often constrained or reshaped according to cultural values. == See also == Akrasia Deindividuation Identical particles Identity formation Indiscernibles Individualistic culture Nekyia Positive disintegration Principle of individuation Rationalization (sociology) Self-actualization == References == == Bibliography == Gilbert Simondon, Du mode d'existence des objets techniques (Méot, 1958; Paris: Aubier, 1989, second edition). (in French) Gilbert Simondon, On the Mode of Existence of Technical Objects, Part 1, link to PDF of 1980 translation. Gilbert Simondon, L'individu et sa genèse physico-biologique (l'individuation à la lumière des notions de forme et d'information) (Paris: PUF, 1964; J.Millon, coll. Krisis, 1995, second edition). (in French) Gilbert Simondon, The Individual and Its Physico-Biological Genesis, Part 1, Part 2, links to HTML files of unpublished 2007 translation. Gilbert Simondon, L'Individuation psychique et collective (1964; Paris: Aubier, 1989). (in French) Bernard Stiegler, Acting Out. Bernard Stiegler, Temps et individuation technique, psychique, et collective dans l’oeuvre de


id: landrace-20260505-0
file: data/en.wikipedia.org/wiki/Landrace-0.md
category: reference
title: Landrace
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Landrace
date_saved: 2026-05-05T07:15:39.109121+00:00
instance: kb-cron
parent: landrace-20260505-0
summary:
A landrace is a domesticated, locally adapted, often traditional variety of a species of animal or plant that has developed over time, through adaptation to its natural and cultural environment of agriculture and pastoralism, and due to isolation from other populations of the species. Landraces are distinct from cultivars and from standard breeds.| Landrace dogs are commonly referenced. They typically have distinct ecological and behavioral characteristics that evolutionally developed in certain nations and locales, especially those with a history of colonization. A significant proportion of farmers around the world grow landrace crops, and most plant landraces are associated with traditional agricultural systems. Landraces of many crops have probably been grown for millennia. Increasing reliance upon modern plant cultivars that are bred to be uniform has led to a reduction in biodiversity, because most of the genetic diversity of domesticated plant species lies in landraces and other traditionally used varieties. Some farmers using scientifically improved varieties also continue to raise landraces for agronomic reasons that include better adaptation to the local environment, lower fertilizer requirements, lower cost, and better disease resistance. Cultural and market preferences for landraces include culinary uses and product attributes such as texture, color, or ease of use.


id: landrace-20260505-1
file: data/en.wikipedia.org/wiki/Landrace-1.md
category: reference
title: Landrace
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Landrace
date_saved: 2026-05-05T07:15:39.109121+00:00
instance: kb-cron
parent: landrace-20260505-0
summary:
=== Autochthonous and allochthonous landraces === A landrace native to, or produced for a long time within the agricultural system in which it is found is referred to as an autochthonous landrace, while a more recently introduced one is termed an allochthonous landrace. Within academic agronomy, the term autochthonous landrace is sometimes used with a more technical, productivity-related definition, synthesized by A. C. Zeven from previous definitions beginning with Mansholt's: "an autochthonous landrace is a variety with a high capacity to tolerate biotic and abiotic stress, resulting in a high yield stability and an intermediate yield level under a low input agricultural system." The terms autochthonous and allochthonous are most often applied to plants, with animals more often being referred to as indigenous or native. Examples of references in sources to long-term local landraces of livestock include constructions such as "indigenous landraces of sheep", and "Leicester Longwool sheep were bred to the native landraces of the region". Some usage of autochthonous does occur in reference to livestock, e.g. "autochthonous races of cattle such as the Asturian mountain cattle – Ratina and Casina – and Tudanca cattle." == Biodiversity and conservation == A significant proportion of farmers around the world grow


id: landrace-20260505-2
file: data/en.wikipedia.org/wiki/Landrace-2.md
category: reference
title: Landrace
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Landrace
date_saved: 2026-05-05T07:15:39.109121+00:00
instance: kb-cron
parent: landrace-20260505-0
summary:
The label landrace includes regional cultigens that are genetically heterogeneous, but with enough characteristics in common to permit their recognition as a group. These characteristics are used by farmers to manage diversity and purity within landraces. In some cultures, the development of new landraces is typically limited to members of specific social groups, such as women or shaman. Maintaining existing landraces, like developing new landraces, requires that farmers be able to identify crop-specific characteristics and that those characteristics are passed on to following generations. Over time, the process of identifying the distinguishing characteristic or features of a new landrace is reinforced by cultivation processes; for example, descendants of a plant that is notably drought tolerant may become iteratively more so through selective breeding as farmers regard it as better for dry areas and prioritize planting it in those locations. This is one way in which farming systems can develop a portfolio of landraces over time that have specific ecological niches and uses. Conversely, modern cultivars can also be developed into a landrace over time when farmers save seed and practice selective breeding. Although landraces are often discussed once they have become endemic to a particular geographical region, landraces have always


id: liana-20260505-0
file: data/en.wikipedia.org/wiki/Liana-0.md
category: reference
title: Liana
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Liana
date_saved: 2026-05-05T07:15:41.589127+00:00
instance: kb-cron
parent: liana-20260505-0
summary:
A liana ( lee-ANN-ə, also -⁠AH-nə) is a long-stemmed woody vine that is rooted in the soil at ground level and uses trees, as well as other means of vertical support, to climb up to the canopy in search of direct sunlight. The word liana does not refer to a taxonomic grouping, but rather a habit of plant growth—much like tree or shrub. It comes from standard French liane, itself from an Antilles French dialect word meaning 'to sheave'. == Ecology == Lianas are characteristic of tropical moist broadleaf forests (especially seasonal forests), but may be found in temperate rainforests and temperate deciduous forests. There are also temperate lianas, for example the members of the Clematis or Vitis (wild grape) genera. Lianas can form bridges in the forest canopy, providing arboreal animals—including ants and many other invertebrates, lizards, rodents, sloths, monkeys, and lemurs—with paths through the forest. For example, in the Eastern tropical forests of Madagascar many lemurs achieve higher mobility from the web of lianas draped among the vertical tree species. Many lemurs prefer trees with lianas because of their roots. Lianas are parasitic, they do not derive nutrients directly from host trees, but live on and indirectly derive


id: earliest-known-life-forms-20260505-0
file: data/en.wikipedia.org/wiki/Earliest_known_life_forms-0.md
category: reference
title: Earliest known life forms
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Earliest_known_life_forms
date_saved: 2026-05-05T07:15:42.867278+00:00
instance: kb-cron
parent: earliest-known-life-forms-20260505-0
summary:
The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia. The earliest evidence of life found in a stratigraphic unit, not just a single mineral grain, is the 3.7 Ga metasedimentary rocks containing graphite from the Isua Supracrustal Belt in Greenland. The earliest direct known life on Earth are stromatolite fossils which have been found in 3.480-billion-year-old geyserite uncovered in the Dresser Formation of the Pilbara Craton of Western Australia. Various microfossils of microorganisms have been found in 3.4 Ga rocks, including 3.465-billion-year-old Apex chert rocks from the same Australian craton region, and in 3.42 Ga hydrothermal vent precipitates from Barberton, South Africa. Much later in the geologic record, likely starting in 1.73 Ga, preserved molecular compounds of biologic origin are indicative of aerobic life. Therefore, the earliest time for the origin of life on Earth is at least 3.5 billion years ago and possibly as early as 4.1 billion years ago—not long after the oceans formed 4.5 billion years ago and after the formation of the Earth 4.54 billion years ago. == Biospheres == Earth


id: earliest-known-life-forms-20260505-1
file: data/en.wikipedia.org/wiki/Earliest_known_life_forms-1.md
category: reference
title: Earliest known life forms
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Earliest_known_life_forms
date_saved: 2026-05-05T07:15:42.867278+00:00
instance: kb-cron
parent: earliest-known-life-forms-20260505-0
summary:
Stromatolites are laminated sedimentary structures created by photosynthetic organisms as they establish a microbial mat on a sediment surface. An important distinction for biogenicity is their convex-up structures and wavy laminations, which are typical of microbial communities who build preferentially toward the sun. A disputed report of stromatolites is from the 3.7 Ga Isua metasediments that show convex-up, conical, and domical morphologies. Further mineralogical analysis disagrees with the initial findings of internal convex-up laminae, a critical criterion for stromatolite identification, suggesting that the structures may be deformation features (i.e. boudins) caused by extensional tectonics in the Isua Supracrustal Belt. The earliest direct evidence of life are stromatolites found in 3.48 billion-year-old chert in the Dresser formation of the Pilbara Craton in Western Australia. Several features in these fossils are difficult to explain with abiotic processes, for example, the thickening of laminae over flexure crests that is expected from more sunlight. Sulfur isotopes from barite veins in the stromatolites also favor a biologic origin. However, while most scientists accept their biogenicity, abiotic explanations for these fossils cannot be fully discarded due to their hydrothermal depositional environment and debated geochemical evidence. Most archean stromatolites older than 3.0 Ga are found in Australia


id: earliest-known-life-forms-20260505-2
file: data/en.wikipedia.org/wiki/Earliest_known_life_forms-2.md
category: reference
title: Earliest known life forms
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Earliest_known_life_forms
date_saved: 2026-05-05T07:15:42.867278+00:00
instance: kb-cron
parent: earliest-known-life-forms-20260505-0
summary:
While current geochemical evidence dates the origin of life to possibly as early as 4.1 Ga, and fossil evidence shows life at 3.5 Ga, some researchers speculate that life may have started nearly 4.5 billion years ago. According to biologist Stephen Blair Hedges, "If life arose relatively quickly on Earth ... then it could be common in the universe." The possibility that terrestrial life forms may have been seeded from outer space has been considered. In January 2018, a study found that 4.5 billion-year-old meteorites found on Earth contained liquid water along with prebiotic complex organic substances that may be ingredients for life. === Hydrothermal vents === Hydrothermal vents have long been hypothesized to be the grounds from which life originated. The properties of ancient hydrothermal vents, such as the geochemistry, pressure, and temperatures, have the potential to create organic molecules from inorganic molecules. In experiments performed by NASA, it was shown that the organic compounds formate and methane could be created from inorganics in the conditions of ancient hydrothermal vents. The production of organic molecules could have led to the formation of more complex organic molecules, such as amino acids that can eventually form RNA or DNA. === Darwin's


id: live-crown-20260505-0
file: data/en.wikipedia.org/wiki/Live_crown-0.md
category: reference
title: Live crown
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Live_crown
date_saved: 2026-05-05T07:15:44.042313+00:00
instance: kb-cron
parent: live-crown-20260505-0
summary:
The live crown is the top part of a tree, the part that has green leaves (as opposed to the bare trunk, bare branches, and dead leaves). The ratio of the size of a tree's live crown to its total height is used in estimating its health and its level of competition with neighboring trees. This is referred to as the Live Crown Ratio (LCR). == References ==


id: matriphagy-20260505-0
file: data/en.wikipedia.org/wiki/Matriphagy-0.md
category: reference
title: Matriphagy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Matriphagy
date_saved: 2026-05-05T07:15:55.810435+00:00
instance: kb-cron
parent: matriphagy-20260505-0
summary:
Matriphagy is the consumption of the mother by her offspring. The behavior generally takes place within the first few weeks of life and has been documented in some species of insects, nematode worms, pseudoscorpions, and other arachnids as well as in caecilian amphibians. The specifics of how matriphagy occurs varies among different species. However, the process is best-described in the desert spider (Stegodyphus lineatus), where the mother harbors nutritional resources for her young through food consumption. The mother can regurgitate small portions of food for her growing offspring, but between 1–2 weeks after hatching, the progeny capitalize on this food source by eating her alive. Typically, offspring only feed on their biological mother as opposed to other females in the population. In other arachnid species, matriphagy occurs after the ingestion of nutritional eggs known as trophic eggs (e.g. Black lace-weaver Amaurobius ferox, crab spider Australomisidia ergandros). It involves different techniques for killing the mother, such as transfer of poison via biting and sucking to cause a quick death (e.g. Black lace-weaver) or continuous sucking of the hemolymph, resulting in a more gradual death (e.g. Crab spider). The behavior is less well described but follows a similar pattern in species such


id: matriphagy-20260505-1
file: data/en.wikipedia.org/wiki/Matriphagy-1.md
category: reference
title: Matriphagy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Matriphagy
date_saved: 2026-05-05T07:15:55.810435+00:00
instance: kb-cron
parent: matriphagy-20260505-0
summary:
==== Anechura harmandi ==== Anechura harmandi is the only species of earwigs that has been currently documented to exhibit matriphagy. Mothers in this particular species of earwigs have been found to reproduce during colder temperatures. This is mainly for the purpose of avoiding predation and maximizing their offspring's survival, since females are unable to produce a second clutch. Due to the cold temperature, there is a scarcity of available nutrients when the offspring hatch, which is why the offspring end up consuming their mother. === Pseudoscorpions === ==== Paratemnoides nidificator ==== Matriphagy in this species of pseudoscorpions is usually observed during times of food scarcity. After their offspring hatch, mothers exit their nests and wait to be consumed. Offspring follow their mothers out of the nest where they grab onto her legs and proceed to feed through her leg joints, similar to that of Australomisidia ergandros. Females of this species are able to produce more than one clutch of offspring if their first clutch was unsuccessful. Matriphagy in this species has been predicted to prevent cannibalism between siblings as well. == Evolution == The adaptive value of matriphagy is based on the benefits provided to the offspring and the costs


id: matriphagy-20260505-2
file: data/en.wikipedia.org/wiki/Matriphagy-2.md
category: reference
title: Matriphagy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Matriphagy
date_saved: 2026-05-05T07:15:55.810435+00:00
instance: kb-cron
parent: matriphagy-20260505-0
summary:
The Taita African caecilian Boulengerula taitana is an oviparous (egg-laying) caecilian whose skin transforms in brooding females to supply nutrients to growing offspring. The offspring are born with specific dentition that they can use to peel and eat the outer epidermal layer of their mother's skin. Young move around their mother's bodies, using their lower jaws to lift and peel the mother's skin while vigorously pressing their heads against her abdomen. To account for this, the epidermis of brooding females can be up to twice the thickness of non-brooding females. Viviparous (developing in the mother) caecilians on the other hand, have specialized fetal dentition which can be used for scraping lipid-rich secretions and cellular materials from the maternal oviduct lining. The ringed caecilian Siphonops annulatus, an oviparous caecilian, exhibits characteristics similar to viviparous caecilians. Mothers have paler skin tones than non-attending females, suggesting that offspring feed on glandular secretions on the mother's skin—a process that resembles mammalian lactation. This scraping method is different from the peeling actions performed by oviparous caecilians. For both oviparous and viviparous caecilians, delayed investment is a common benefit. Providing nutrition through the skin allows for redirection of nutrients, yielding fewer and larger offspring than caecilians


id: modularity-biology-20260505-0
file: data/en.wikipedia.org/wiki/Modularity_(biology)-0.md
category: reference
title: Modularity (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Modularity_(biology)
date_saved: 2026-05-05T07:15:56.996480+00:00
instance: kb-cron
parent: modularity-biology-20260505-0
summary:
Modularity refers to the ability of a system to organize discrete, individual units that can overall increase the efficiency of network activity and, in a biological sense, facilitates selective forces upon the network. Modularity is observed in all model systems, and can be studied at nearly every scale of biological organization, from molecular interactions all the way up to the whole organism. == Evolution of Modularity == The exact evolutionary origins of biological modularity has been debated since the 1990s. In the mid 1990s, Günter Wagner argued that modularity could have arisen and been maintained through the interaction of four evolutionary modes of action: [1] Selection for the rate of adaptation: If different complexes evolve at different rates, then those evolving more quickly reach fixation in a population faster than other complexes. Thus, common evolutionary rates could be forcing the genes for certain proteins to evolve together while preventing other genes from being co-opted unless there is a shift in evolutionary rate. [2] Constructional selection: When a gene exists in many duplicated copies, it may be maintained because of the many connections it has (also termed pleiotropy). There is evidence that this is so following whole genome duplication, or duplication


id: molluscivore-20260505-0
file: data/en.wikipedia.org/wiki/Molluscivore-0.md
category: reference
title: Molluscivore
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molluscivore
date_saved: 2026-05-05T07:15:58.235461+00:00
instance: kb-cron
parent: molluscivore-20260505-0
summary:
A molluscivore is a carnivorous animal that specialises in feeding on molluscs such as gastropods, bivalves, brachiopods and cephalopods. Known molluscivores include numerous predatory (and often cannibalistic) molluscs, (e.g. octopuses, murexes, decollate snails and oyster drills), arthropods such as crabs and firefly larvae, and vertebrates such as fish, birds and mammals. Molluscivory is performed in a variety of ways with some animals highly adapted to this method of feeding. A similar behaviour, durophagy, describes the feeding of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled molluscs, or crabs. == Description == Molluscivory can be performed in several ways: In some cases, the mollusc prey are simply swallowed entire, including the shell, whereupon the prey is killed through suffocation and/or exposure to digestive enzymes. Only cannibalistic sea slugs, snail-eating cone shells of the taxon Coninae, and some sea anemones use this method. One method, used especially by vertebrate molluscivores, is to break the shell, either by exerting force on the shell until it breaks, often by biting the shell, like with oyster crackers, mosasaurs, and placodonts, or hammering at the shell, e.g. oystercatchers and crabs, or by simply dashing the mollusc on a rock (e.g. song thrushes,


id: molluscivore-20260505-1
file: data/en.wikipedia.org/wiki/Molluscivore-1.md
category: reference
title: Molluscivore
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Molluscivore
date_saved: 2026-05-05T07:15:58.235461+00:00
instance: kb-cron
parent: molluscivore-20260505-0
summary:
Cone snails: Some cone snails hunt and eat other kinds of snails, such as cowries, olive shells, turbo snails, and conch snails, while others will eat other cone snails. Conus marmoreus and Conus omaria are able to kill and swallow prey that are larger than themselves; some Conus species can swallow prey that weigh up to half of their own weight. Snails' bodies are attached to their shell by a columellar muscle that holds onto the columella, the axis of the snail. This muscle also allows the snail to retract back into its shell. If this muscle is broken, the snail will lose its shell and die. It is hard to detach this muscle in a live snail, or even in a dead snail. It is thought that the conotoxins in the venom of cone snails are able to completely relax this muscle so that the body can be pulled out from its shell. The cone snail uses its foot to hold the shell of its prey. Using a strong, steady pulling motion, the body of the snail can be forced out and then swallowed whole. Complete digestion of a snail can take many hours, even days. Starfish: Primitive starfish,


id: monoclonality-20260505-0
file: data/en.wikipedia.org/wiki/Monoclonality-0.md
category: reference
title: Monoclonality
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Monoclonality
date_saved: 2026-05-05T07:15:59.386578+00:00
instance: kb-cron
parent: monoclonality-20260505-0
summary:
In biology, monoclonality refers to the state of a line of cells that have been derived from a single clonal origin. Thus, "monoclonal cells" can be said to form a single clone. The term monoclonal comes from Ancient Greek monos 'alone, single' and klonos 'clone'. The process of replication can occur in vivo, or may be stimulated in vitro for laboratory manipulations. The use of the term typically implies that there is some method to distinguish between the cells of the original population from which the single ancestral cell is derived, such as a random genetic alteration, which is inherited by the progeny. Common usages of this term include: Monoclonal antibody: a single hybridoma cell, which by chance includes the appropriate V(D)J recombination to produce the desired antibody, is cloned to produce a large population of identical cells. In informal laboratory jargon, the monoclonal antibodies isolated from cell culture supernatants of these hybridoma clones (hybridoma lines) are simply called monoclonals. Monoclonal neoplasm (tumor): A single aberrant cell which has undergone carcinogenesis reproduces itself into a cancerous mass. Monoclonal plasma cell (also called plasma cell dyscrasia): A single aberrant plasma cell which has undergone carcinogenesis reproduces itself, which in some cases


id: monogastric-20260505-0
file: data/en.wikipedia.org/wiki/Monogastric-0.md
category: reference
title: Monogastric
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Monogastric
date_saved: 2026-05-05T07:16:00.599009+00:00
instance: kb-cron
parent: monogastric-20260505-0
summary:
A monogastric organism defines one of the many types of digestive tracts found among different species of animals. The defining feature of a monogastric is that it has a simple single-chambered stomach (one stomach). A monogastric can be classified as an herbivore, an omnivore (facultative carnivore), or a carnivore (obligate carnivore). Herbivores have a plant-based diet, omnivores have a plant and meat-based diet, and carnivores only eat meat. Examples of monogastric herbivores include horses, rabbits, and guinea pigs. Examples of monogastric omnivores include humans, pigs, and hamsters. Furthermore, there are monogastric carnivores such as cats and seals. A monogastric digestive tract is slightly different from other types of digestive tracts such as a ruminant and avian. Ruminant organisms have a four-chambered complex stomach and avian organisms have a two-chambered stomach. An example of a ruminant and avian are cattle and chickens. == Digestive System == The digestive system of a monogastric is a one way tract that can be divided into two section: the foregut and the hindgut. The foregut consists of the mouth, esophagus, stomach, and small intestine. The hindgut consists of the large intestine, cecum, colon, and rectum. Each organ has its own role in the break down


id: mycobiota-20260505-0
file: data/en.wikipedia.org/wiki/Mycobiota-0.md
category: reference
title: Mycobiota
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Mycobiota
date_saved: 2026-05-05T07:16:02.079658+00:00
instance: kb-cron
parent: mycobiota-20260505-0
summary:
Mycobiota (plural noun, no singular) are a group of all the fungi present in a particular geographic region (e.g. "the mycobiota of Ireland") or habitat type (e.g. "the mycobiota of cocoa"). An analogous term for Mycobiota is funga. == Human mycobiota == Mycobiota exist on the surface and in the gastrointestinal system of humans. There are as many as sixty-six genera and 184 species in the gastrointestinal tract of healthy people. Most of these are in the Candida genera. Though found to be present on the skin and in the gi tract in healthy individuals, the normal resident mycobiota can become pathogenic in those who are immunocompromised. Such multispecies infections lead to higher mortalities. In addition hospital-acquired infections by C. albicans have become a cause of major health concerns. A high mortality rate of 40-60% is associated with systemic infection. The best-studied of these are Candida species due to their ability to become pathogenic in immunocompromised and even in healthy hosts. Yeasts are also present on the skin, such as Malassezia species, where they consume oils secreted from the sebaceous glands. Pityrosporum (Malassezia) ovale, which is lipid-dependent and found only on humans. P. ovale was later divided into two species,


id: natural-competence-20260505-0
file: data/en.wikipedia.org/wiki/Natural_competence-0.md
category: reference
title: Natural competence
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Natural_competence
date_saved: 2026-05-05T07:16:03.334926+00:00
instance: kb-cron
parent: natural-competence-20260505-0
summary:
In microbiology, genetics, cell biology, and molecular biology, competence is the ability of a cell to alter its genetics by taking up extracellular DNA from its environment through a process called transformation. Competence can be differentiated between natural competence and induced or artificial competence. Natural competence is a genetically specified ability of bacteria that occurs under natural conditions as well as in the laboratory. Artificial competence arises when cells in laboratory cultures are treated to make them transiently permeable to DNA. Competence allows for rapid adaptation and DNA repair of the cell. == History == Natural competence was discovered by Frederick Griffith in 1928, when he showed that a preparation of killed cells of a pathogenic bacterium contained something that could transform related non-pathogenic cells into the pathogenic type. In 1944 Oswald Avery, Colin MacLeod, and Maclyn McCarty demonstrated that this 'transforming factor' was pure DNA. This was the first compelling evidence that DNA carries the genetic information of the cell. Since then, natural competence has been studied in a number of different bacteria, particularly Bacillus subtilis, Streptococcus pneumoniae, Neisseria gonorrhoeae, Haemophilus influenzae and members of the Acinetobacter genus. Areas of active research include the mechanisms of DNA transport, the


id: natural-competence-20260505-1
file: data/en.wikipedia.org/wiki/Natural_competence-1.md
category: reference
title: Natural competence
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Natural_competence
date_saved: 2026-05-05T07:16:03.334926+00:00
instance: kb-cron
parent: natural-competence-20260505-0
summary:
=== Hypothesis of DNA as food === The second hypothesis, DNA as food, relies on the fact that cells that take up DNA inevitably acquire the nucleotides the DNA consists of, and, because nucleotides are needed for DNA and RNA synthesis and are expensive to synthesize, these may make a significant contribution to the cell's energy budget. Some naturally competent bacteria also secrete nucleases into their surroundings, and all bacteria can take up the free nucleotides these nucleases generate from environmental DNA. The energetics of DNA uptake are not understood in any system, so it is difficult to compare the efficiency of nuclease secretion to that of DNA uptake and internal degradation. In principle the cost of nuclease production and the uncertainty of nucleotide recovery must be balanced against the energy needed to synthesize the uptake machinery and to pull DNA in. Other important factors are the likelihoods that nucleases and competent cells will encounter DNA molecules, the relative inefficiencies of nucleotide uptake from the environment and from the periplasm (where one strand is degraded by competent cells), and the advantage of producing ready-to-use nucleotide monophosphates from the other strand in the cytoplasm. Another complicating factor is the self-bias of


id: obligate-20260505-0
file: data/en.wikipedia.org/wiki/Obligate-0.md
category: reference
title: Obligate
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Obligate
date_saved: 2026-05-05T07:16:05.776718+00:00
instance: kb-cron
parent: obligate-20260505-0
summary:
As an adjective, obligate means "by necessity" (antonym facultative) and is used mainly in biology in phrases such as: Obligate aerobe, an organism that cannot survive without oxygen Obligate anaerobe, an organism that cannot survive in the presence of oxygen Obligate air-breather, a term used in fish physiology to describe those that respire entirely from the atmosphere Obligate biped, an animal that relies solely on walking or running on its two hind limbs for locomotion Obligate carnivore, an organism dependent for survival on a diet of animal flesh. Obligate chimerism, a kind of organism with two distinct sets of DNA, always Obligate hibernation, a state of inactivity in which some organisms survive conditions of insufficiently available resources. Obligately intracellular parasite, a parasitic microorganism that cannot reproduce without entering a suitable host cell Obligate necrophage, an animal that uses carrion as its sole or main food source and depends on carrion for survival or reproduction Obligate parasite, a parasite that cannot reproduce without exploiting a suitable host Obligate photoperiodic plant, a plant that requires sufficiently long or short nights before it initiates flowering, germination or similarly functions Obligate scavenger, an animal that uses decaying biomass (e.g. carrion, dead plant material) as


id: oophagy-20260505-0
file: data/en.wikipedia.org/wiki/Oophagy-0.md
category: reference
title: Oophagy
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Oophagy
date_saved: 2026-05-05T07:16:07.109473+00:00
instance: kb-cron
parent: oophagy-20260505-0
summary:
Oophagy ( oh-OFF-ə-jee) or ovophagy, literally "egg eating", is the practice of embryos feeding on eggs produced by the ovary while still inside the mother's uterus. The word oophagy is formed from the classical Greek ᾠόν (ōion, "egg") and classical Greek φᾱγεῖν (phāgein, "to eat"). In contrast, adelphophagy is the cannibalism of a multi-celled embryo. Oophagy is thought to occur in all sharks in the order Lamniformes and has been recorded in the bigeye thresher (Alopias superciliosus), the pelagic thresher (A. pelagicus), the shortfin mako (Isurus oxyrinchus) and the porbeagle (Lamna nasus) among others. It also occurs in the tawny nurse shark (Nebrius ferrugineus), and in the family Pseudotriakidae. This practice may lead to larger embryos or prepare the embryo for a predatory lifestyle. There are variations in the extent of oophagy among the different shark species. The grey nurse shark (Carcharias taurus) practices intrauterine cannibalism, the first developed embryo consuming both additional eggs and any other developing embryos. Slender smooth-hounds (Gollum attenuatus), form egg capsules which contain 30-80 ova, within which only one ovum develops; the remaining ova are ingested and their yolks stored in its external yolk sac. The embryo then proceeds to develop normally, without ingesting further


id: paratype-20260505-0
file: data/en.wikipedia.org/wiki/Paratype-0.md
category: reference
title: Paratype
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Paratype
date_saved: 2026-05-05T07:16:09.515534+00:00
instance: kb-cron
parent: paratype-20260505-0
summary:
In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Often there is more than one paratype. Paratypes are usually held in museum research collections. The exact meaning of the term paratype when it is used in zoology is not the same as the meaning when it is used in botany. In both cases however, this term is used in conjunction with holotype. == Zoology == In zoological nomenclature, a paratype is officially defined as "Each specimen of a type series other than the holotype." In turn, this definition relies on the definition of a "type series". A type series is the material (specimens of organisms) that was cited in the original publication of the new species or subspecies, and was not excluded from being type material by the author (this exclusion can be implicit, e.g., if an author mentions "paratypes" and then subsequently mentions "other material examined", the latter are not included in the type series), nor referred to as a variant, or only dubiously


id: perennation-20260505-0
file: data/en.wikipedia.org/wiki/Perennation-0.md
category: reference
title: Perennation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Perennation
date_saved: 2026-05-05T07:16:13.223016+00:00
instance: kb-cron
parent: perennation-20260505-0
summary:
In botany, perennation is the ability of organisms, particularly plants, to survive from one germinating season to another, especially under unfavourable conditions such as drought or winter cold. It typically involves development of a perennating organ, which stores enough nutrients to sustain the organism during the unfavourable season, and develops into one or more new plants the following year. Perennation is done by stem in plants to tide over unfavourable condition. Common forms of perennating organs are storage organs (e.g. bulbs, tubers, rhizomes and corm), buds and oxalis . Perennation is closely related with vegetative reproduction, as the organisms commonly use the same organs for both survival and reproduction. == See also == Overwintering Plant pathology Sclerotium Turion (botany) == References ==


id: permissiveness-endocrinology-20260505-0
file: data/en.wikipedia.org/wiki/Permissiveness_(endocrinology)-0.md
category: reference
title: Permissiveness (endocrinology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Permissiveness_(endocrinology)
date_saved: 2026-05-05T07:16:15.770918+00:00
instance: kb-cron
parent: permissiveness-endocrinology-20260505-0
summary:
In endocrinology, permissiveness is a biochemical phenomenon in which the presence of one hormone is required in order for another hormone to exert its full effects on a target cell. Hormones can interact in permissive, synergistic, or antagonistic ways. The chemical classes of hormones include amines, polypeptides, glycoproteins and steroids. Permissive hormones act as precursors to active hormones and may be classified as either prohormones or prehormones. It stimulate the formation of receptors of that hormone. == Examples == Thyroid hormone increases the number of beta-adrenergic receptors available for epinephrine at the latter's target cell, thereby increasing epinephrine's effect on that cell. Specially in cardiac cell. Without the thyroid hormone, epinephrine would have only a weak effect. Cortisol is required for the response of vascular and bronchial smooth muscle to catecholamines. Cortisol is also required for the lipolytic effect of catecholamines, ACTH, and growth hormone on fat cells. Cortisol is also required for the calorigenic effects of glucagon and catecholamines. The effects of a hormone in the body depend on its concentration. Permissive actions of glucocorticoids like cortisol generally occur at low concentrations. Abnormally high amounts of a hormone can result in atypical effects. Glucocorticoids function by attaching to cytoplasmic


id: photoautotroph-20260505-0
file: data/en.wikipedia.org/wiki/Photoautotroph-0.md
category: reference
title: Photoautotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photoautotroph
date_saved: 2026-05-05T07:16:16.929231+00:00
instance: kb-cron
parent: photoautotroph-20260505-0
summary:
Photoautotrophs are organisms that can utilize light energy from sunlight, and elements (such as carbon) from inorganic compounds, to produce organic materials needed to sustain their own metabolism (i.e. autotrophy). Such biological activities are known as photosynthesis, and examples of such organisms include plants, algae and cyanobacteria. Eukaryotic photoautotrophs absorb photonic energy through the photopigment chlorophyll (a porphyrin derivative) in their endosymbiont chloroplasts, while prokaryotic photoautotrophs use chlorophylls and bacteriochlorophylls present in free-floating cytoplasmic thylakoids. Plants, algae, and cyanobacteria perform oxygenic photosynthesis that produces oxygen as a byproduct, while some bacteria perform anoxygenic photosynthesis. == Origin and the Great Oxidation Event == Chemical and geological evidence indicate that photosynthetic cyanobacteria existed about 2.6 billion years ago and anoxygenic photosynthesis had been taking place since a billion years before that. Oxygenic photosynthesis was the primary source of free oxygen and led to the Great Oxidation Event roughly 2.4 to 2.1 billion years ago during the Neoarchean-Paleoproterozoic boundary. Although the end of the Great Oxidation Event was marked by a significant decrease in gross primary productivity that eclipsed extinction events, the development of aerobic respiration enabled more energetic metabolism of organic molecules, leading to symbiogenesis and the evolution of eukaryotes, and allowing


id: photoheterotroph-20260505-0
file: data/en.wikipedia.org/wiki/Photoheterotroph-0.md
category: reference
title: Photoheterotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photoheterotroph
date_saved: 2026-05-05T07:16:18.165326+00:00
instance: kb-cron
parent: photoheterotroph-20260505-0
summary:
Photoheterotrophs (Gk: photo = light, hetero = (an)other, troph = nourishment) are heterotrophic phototrophs—that is, they are organisms that use light for energy, but cannot use carbon dioxide as their sole carbon source. Consequently, they use organic compounds from the environment to satisfy their carbon requirements; these compounds include carbohydrates, fatty acids, and alcohols. Examples of photoheterotrophic organisms include purple non-sulfur bacteria, green non-sulfur bacteria, and heliobacteria. These microorganisms are ubiquitous in aquatic habitats, occupy unique niche-spaces, and contribute to global biogeochemical cycling. Recent research has also indicated that the oriental hornet and some aphids may be able to use light to supplement their energy supply. Some recent research has even found hints of photoheterotrophy in a few eukaryotes, though it's still being studied. == Research == Studies have shown that mammalian mitochondria can also capture light and synthesize ATP when mixed with pheophorbide, a light-capturing metabolite of chlorophyll. Research demonstrated that the same metabolite when fed to the worm Caenorhabditis elegans leads to increase in ATP synthesis upon light exposure, along with an increase in life span. Furthermore, inoculation experiments suggest that mixotrophic Ochromonas danica (i.e., Golden algae)—and comparable eukaryotes—favor photoheterotrophy in oligotrophic (i.e., nutrient-limited) aquatic habitats. This preference


id: photoheterotroph-20260505-1
file: data/en.wikipedia.org/wiki/Photoheterotroph-1.md
category: reference
title: Photoheterotroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photoheterotroph
date_saved: 2026-05-05T07:16:18.165326+00:00
instance: kb-cron
parent: photoheterotroph-20260505-0
summary:
=== Distribution and niche partitioning === Photoheterotrophs are found in many different water-based environments like oceans, lakes, and even rice paddies. They tend to live near the surface of the water, where there's enough light but not much carbon dioxide. Photoheterotrophs—either 1) cyanobacteria (i.e. facultative heterotrophs in nutrient-limited environments like Synechococcus and Prochlorococcus), 2) aerobic anoxygenic photoheterotrophic bacteria (AAP; employing bacteriochlorophyll-based reaction centers), 3) proteorhodopsin (PR)-containing bacteria and archaea, and 4) heliobacteria (i.e., the only phototroph with bacteriochlorophyll g pigments, or Gram-positive membrane) are found in various aquatic habitats including oceans, stratified lakes, rice fields, and environmental extremes. In oceans' photic zones, up to 10% of bacterial cells are capable of AAP, whereas greater than 50% of net marine microorganisms house PR—reaching up to 90% in coastal biomes. As demonstrated in inoculation experiments, photoheterotrophy may provide these planktonic microbes competitive advantages 1) relative to chemoheterotrophs in oligotrophic (i.e., nutrient-poor) environments via increased nutrient use-efficiency (i.e., organic carbon fuels biosynthesis, excessively, versus energy production) and 2) by eliminating investment in physiologically costly autotrophic enzymes/complexes (RuBisCo and PSII). Furthermore, in Arctic oceans, AAP and PR photoheterotrophs are prominent in ice-covered regions during wintertime per light scarcity. Lastly, seasonal turnover has been observed


id: photokinesis-20260505-0
file: data/en.wikipedia.org/wiki/Photokinesis-0.md
category: reference
title: Photokinesis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photokinesis
date_saved: 2026-05-05T07:16:19.384164+00:00
instance: kb-cron
parent: photokinesis-20260505-0
summary:
Photokinesis is a change in the velocity of movement of an organism as a result of changes in light intensity. The alteration in speed is independent of the direction from which the light is shining. Photokinesis is described as positive if the velocity of travel is greater with an increase in light intensity and negative if the velocity is slower. If a group of organisms with a positive photokinetic response is swimming in a partially shaded environment, there will be fewer organisms per unit of volume in the sunlit portion than in the shaded parts. This may be beneficial for the organisms if it is unfavourable to their predators, or it may be propitious to them in their quest for prey. In photosynthetic prokaryotes, the mechanism for photokinesis appears to be an energetic process. In cyanobacteria, for example, an increase in illumination results in an increase of photophosphorylation which enables an increase in metabolic activity. However the behaviour is also found among eukaryotic microorganisms, including those like Astasia longa which are not photosynthetic, and in these, the mechanism is not fully understood. In Euglena gracilis, the rate of swimming has been shown to speed up with increased light intensity until


id: photoperiodism-20260505-0
file: data/en.wikipedia.org/wiki/Photoperiodism-0.md
category: reference
title: Photoperiodism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photoperiodism
date_saved: 2026-05-05T07:16:20.769311+00:00
instance: kb-cron
parent: photoperiodism-20260505-0
summary:
Photoperiod is the change of day length over the seasons. Earth's rotation around its axis produces 24-hour changes in light (daytime) and dark (night) cycles on Earth. The length of the light and dark in each phase varies across the seasons due to the axial tilt of Earth. The photoperiod defines the length of the light. For example, in summer the length of light could be 16 hours while the dark is 8 hours, whereas in winter the length of day could be 8 hours, while the dark is 16 hours. Importantly, the axial tilt of the Earth causes the opposing seasons in the Northern and Southern Hemispheres. Photoperiodism is the physiological reaction of organisms to the length of light or a dark period. It occurs in plants and animals. Plant photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light and dark periods. They are classified under three groups according to the photoperiods: short-day plants, long-day plants, and day-neutral plants. In animals, photoperiodism (sometimes called seasonality) is the suite of physiological changes that occur in response to changes in day length. This allows animals to respond to a temporally changing environment associated


id: photoperiodism-20260505-1
file: data/en.wikipedia.org/wiki/Photoperiodism-1.md
category: reference
title: Photoperiodism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Photoperiodism
date_saved: 2026-05-05T07:16:20.769311+00:00
instance: kb-cron
parent: photoperiodism-20260505-0
summary:
Kenaf (Hibiscus cannabinus) Marijuana (Cannabis) Cotton (Gossypium) Rice (Oryza) Sorghum (Sorghum bicolor) Green gram (Mung bean, Vigna radiata) Soybeans (Glycine max) === Day-neutral plants === Day-neutral plants, such as cucumbers, roses, tomatoes, and Ruderalis (autoflowering cannabis) do not initiate flowering based on photoperiodism. Instead, they may initiate flowering after attaining a certain overall developmental stage or age, or in response to alternative environmental stimuli, such as vernalisation (a period of low temperature). == Animals == Day length, and thus knowledge of the season of the year, is vital to many animals. A number of biological and behavioural changes are dependent on this knowledge. Together with temperature changes, photoperiod provokes changes in the color of fur and feathers, migration, entry into hibernation, sexual behaviour, and even the resizing of organs. In insects, sensitivity to photoperiod has been proven to be initiated by photoreceptors located in the brain. Photoperiod can affect insects at different life stages, serving as an environmental cue for physiological processes such as diapause induction and termination, and seasonal morphs. In the water strider Aquarius paludum, for instance, photoperiod conditions during nymphal development have been shown to trigger seasonal changes in wing frequency and also induce diapause, although the


id: phototaxis-20260505-0
file: data/en.wikipedia.org/wiki/Phototaxis-0.md
category: reference
title: Phototaxis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phototaxis
date_saved: 2026-05-05T07:16:22.043277+00:00
instance: kb-cron
parent: phototaxis-20260505-0
summary:
Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from a stimulus of light. This is advantageous for phototrophic organisms as they can orient themselves most efficiently to receive light for photosynthesis. Phototaxis is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite. Phototaxis has been described in microorganisms and algea, insects and other invertebrates, and vertebrates. Typically nocturnal insects can show positive phototaxis, while nocturnal mammals often show negative phototaxis. == Phototaxis in bacteria and archea == Phototaxis can be advantageous for phototrophic bacteria as they can orient themselves most efficiently to receive light for photosynthesis. Phototaxis is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite. Two types of positive phototaxis are observed in prokaryotes (bacteria and archea). The first is called "scotophobotaxis" (from the word "scotophobia"), which is observed only under a microscope. This occurs when a bacterium swims by chance out of the area illuminated by the microscope. Entering darkness signals the cell to reverse flagella rotation direction and reenter the light. The second


id: phototaxis-20260505-1
file: data/en.wikipedia.org/wiki/Phototaxis-1.md
category: reference
title: Phototaxis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phototaxis
date_saved: 2026-05-05T07:16:22.043277+00:00
instance: kb-cron
parent: phototaxis-20260505-0
summary:
The ability to link light perception to control of motility is found in a very wide variety of prokaryotes, indicating that this ability must confer a range of physiological advantages. Most directly, the light environment is crucial to phototrophs as their energy source. Phototrophic prokaryotes are extraordinarily diverse, with a likely role for horizontal gene transfer in spreading phototrophy across multiple phyla. Thus, different groups of phototrophic prokaryotes may have little in common apart from their exploitation of light as an energy source, but it should be advantageous for any phototroph to be able to relocate in search of better light environments for photosynthesis. To do this efficiently requires the ability to control motility in response to integrated information on the intensity of light, the spectral quality of light and the physiological status of the cell. A second major reason for light-controlled motility is to avoid light at damaging intensities or wavelengths: this factor is not confined to photosynthetic bacteria since light (especially in the UV region) can be dangerous to all prokaryotes, primarily because of DNA and protein damage and inhibition of the translation machinery by light-generated reactive oxygen species. Finally, light signals potentially contain rich and complex information


id: phototaxis-20260505-2
file: data/en.wikipedia.org/wiki/Phototaxis-2.md
category: reference
title: Phototaxis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phototaxis
date_saved: 2026-05-05T07:16:22.043277+00:00
instance: kb-cron
parent: phototaxis-20260505-0
summary:
Some protists (unicellular eukaryotes) can also move toward or away from light, by coupling their locomotion strategy with a light-sensing organ. Eukaryotes evolved for the first time in the history of life the ability to follow light direction in three dimensions in open water. The strategy of eukaryotic sensory integration, sensory processing and the speed and mechanics of tactic responses is fundamentally different from that found in prokaryotes. Both single-celled and multi-cellular eukaryotic phototactic organisms have a fixed shape, are polarized, swim in a spiral and use cilia for swimming and phototactic steering. Signalling can happen via direct light-triggered ion currents, adenylyl cyclases or trimeric G-proteins. The photoreceptors used can also be very different (see below). However, signalling in all cases eventually modifies the beating activity of cilia. The mechanics of phototactic orientation is analogous in all eukaryotes. A photosensor with a restricted view angle rotates to scan the space and signals periodically to the cilia to alter their beating, which will change the direction of the helical swimming trajectory. Three-dimensional phototaxis can be found in five out of the six eukaryotic major groups (opisthokonts, Amoebozoa, plants, chromalveolates, excavates, rhizaria). Pelagic phototaxis is present in green algae – it is


id: phototaxis-20260505-3
file: data/en.wikipedia.org/wiki/Phototaxis-3.md
category: reference
title: Phototaxis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phototaxis
date_saved: 2026-05-05T07:16:22.043277+00:00
instance: kb-cron
parent: phototaxis-20260505-0
summary:
Phototaxis has been well studied in the marine ragworm Platynereis dumerilii. Both Platynereis dumerilii trochophore and its metatrochophore larvae are positively phototactic. Phototaxis is mediated by simple eyespots that consists of a pigment cell and a photoreceptor cell. The photoreceptor cell synapses directly onto ciliated cells, which are used for swimming. The eyespots do not give spatial resolution, therefore the larvae are rotating to scan their environment for the direction where the light is coming from. Platynereis dumerilii larvae (nectochaete) can switch between positive and negative phototaxis. Phototaxis there is mediated by two pairs of more complex pigment cup eyes. These eyes contain more photoreceptor cells that are shaded by pigment cells forming a cup. The photoreceptor cells do not synapse directly onto ciliated cells or muscle cells but onto inter-neurons of a processing center. This way the information of all four eye cups can be compared and a low-resolution image of four pixels can be created telling the larvae where the light is coming from. This way the larva does not need to scan its environment by rotating. This is an adaption for living on the bottom of the sea the lifestyle of the larva while scanning rotation is


id: phototaxis-20260505-4
file: data/en.wikipedia.org/wiki/Phototaxis-4.md
category: reference
title: Phototaxis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phototaxis
date_saved: 2026-05-05T07:16:22.043277+00:00
instance: kb-cron
parent: phototaxis-20260505-0
summary:
== Light based vertical movement == A depth can also be selected based on light levels: The brightness decreases with depth, but depends on the weather (e.g. whether it is sunny or cloudy) and the time of the day. Also the color depends on the water depth and dissolved and suspended matter. The only consistent factor is that at a given place, deeper water is darker. In water, light attenuates differently for each wavelength. The UV, violet (> 420 nm), and red (< 500 nm) wavelengths disappear before blue light (470 nm), which penetrates clear water the deepest. The wavelength composition is constant for each depth and is almost independent of time of the day and the weather. To gauge depth, an animal would need two photopigments sensitive to different wavelengths to compare different ranges of the spectrum. Such pigments may be expressed in different structures. Such different structures are found in the polychaete Torrea candida. Its eyes have a main and two accessory retinae. The accessory retinae sense UV-light (λmax = 400 nm) and the main retina senses blue-green light (λmax = 560 nm). If the light sensed from all retinae is compared, the depth can be estimated, and


id: phototroph-20260505-0
file: data/en.wikipedia.org/wiki/Phototroph-0.md
category: reference
title: Phototroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phototroph
date_saved: 2026-05-05T07:16:23.246471+00:00
instance: kb-cron
parent: phototroph-20260505-0
summary:
Phototrophs (from Ancient Greek φῶς, φωτός (phôs, phōtós) 'light' and τροφή (trophḗ) 'nourishment') are organisms that carry out photon capture to acquire energy. They use the energy from light to carry out various cellular metabolic processes. It is a common misconception that phototrophs are obligatorily photosynthetic. Many, but not all, phototrophs photosynthesize: they anabolically convert carbon dioxide into biomolecules to be utilized structurally (e.g. cellulose and membrane lipids), functionally (e.g. vitamins, nucleotides, and amino acids), or as a source for later catabolic processes (e.g. starches, sugars and fats). All phototrophs either use electron transport chains or direct proton pumping to establish an electrochemical gradient, which is utilized by ATP synthase to provide adenosine triphosphate (ATP) for the cell. Phototrophs can be either autotrophs or heterotrophs. If their electron and hydrogen donors are inorganic compounds (e.g., Na2S2O3, as in some purple sulfur bacteria, or H2S, as in some green sulfur bacteria) they can be also called lithotrophs, and so, some photoautotrophs are also called photolithoautotrophs. Examples of phototroph organisms are Rhodobacter capsulatus, Chromatium, and Chlorobium. == History == Originally used with a different meaning, the term took its current definition after Lwoff and collaborators (1946). == Photoautotroph == Most well-known phototrophs


id: phototropism-20260505-0
file: data/en.wikipedia.org/wiki/Phototropism-0.md
category: reference
title: Phototropism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phototropism
date_saved: 2026-05-05T07:16:24.492344+00:00
instance: kb-cron
parent: phototropism-20260505-0
summary:
In biology, phototropism, formerly called heliotropism, is the growth of an organism in response to a light stimulus. Phototropism is most often observed in plants, but can also occur in other organisms such as fungi. The cells on the plant that are farthest from the light contain a hormone called auxin that reacts when phototropism occurs. This causes the plant to have elongated cells on the furthest side from the light. Phototropism is one of the many plant tropisms, or movements, which respond to external stimuli. Growth towards a light source is called positive phototropism, while growth away from light is called negative phototropism. Negative phototropism is not to be confused with skototropism, which is defined as the growth towards darkness, whereas negative phototropism can refer to either the growth away from a light source or towards the darkness. Most plant shoots exhibit positive phototropism, and rearrange their chloroplasts in the leaves to maximize photosynthetic energy and promote growth. Some vine shoot tips exhibit negative phototropism, which allows them to grow towards dark, solid objects and climb them. The combination of phototropism and gravitropism allow plants to grow in the correct direction. == Mechanism == There are several signaling molecules


id: phototropism-20260505-1
file: data/en.wikipedia.org/wiki/Phototropism-1.md
category: reference
title: Phototropism
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Phototropism
date_saved: 2026-05-05T07:16:24.492344+00:00
instance: kb-cron
parent: phototropism-20260505-0
summary:
=== Five models of auxin distribution in phototropism === In 2012, Sakai and Haga outlined how different auxin concentrations could be arising on shaded and lighted side of the stem, giving birth to phototropic response. Five models in respect to stem phototropism have been proposed, using Arabidopsis thaliana as the study plant. First model In the first model incoming light deactivates auxin on the light side of the plant allowing the shaded part to continue growing and eventually bend the plant over towards the light. Second model In the second model light inhibits auxin biosynthesis on the light side of the plant, thus decreasing the concentration of auxin relative to the unaffected side. Third model In the third model there is a horizontal flow of auxin from both the light and dark side of the plant. Incoming light causes more auxin to flow from the exposed side to the shaded side, increasing the concentration of auxin on the shaded side and thus more growth occurring. Fourth model In the fourth model it shows the plant receiving light to inhibit auxin basipetal down to the exposed side, causing the auxin to only flow down the shaded side. Fifth model Model five


id: postglacial-vegetation-20260505-0
file: data/en.wikipedia.org/wiki/Postglacial_vegetation-0.md
category: reference
title: Postglacial vegetation
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Postglacial_vegetation
date_saved: 2026-05-05T07:16:27.073439+00:00
instance: kb-cron
parent: postglacial-vegetation-20260505-0
summary:
Postglacial vegetation refers to plants that colonize the newly exposed substrate after a glacial retreat. The term "postglacial" typically refers to processes and events that occur after the departure of glacial ice or glacial climates. == Climate Influence == Climate change is the main force behind changes in species distribution and abundance. Repeated changes in climate throughout the Quaternary Period are thought to have had a significant impact on the current vegetation species diversity present today. Functional and phylogenetic diversity are considered to be closely related to changing climatic conditions and this indicates that trait differences are extremely important in long term responses to climate change. During the transition from the last glaciation of the Pleistocene to the Holocene period, climate warming resulted in the expansion of taller plants and larger seed bearing plants which resulted in lower proportions of vegetation regeneration. Hence, low temperatures can be strong environmental filters that prevent tall and large-seeded plants from establishing in postglacial environments. Throughout Europe vegetation dynamics within the first half of the Holocene appear to have been influenced mainly by climate and the reorganization of atmospheric circulation associated with the disappearance of the North American ice sheet. This is evident in


id: predation-rates-20260505-0
file: data/en.wikipedia.org/wiki/Predation_rates-0.md
category: reference
title: Predation rates
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Predation_rates
date_saved: 2026-05-05T07:16:28.250216+00:00
instance: kb-cron
parent: predation-rates-20260505-0
summary:
The term predation rate refers to the frequency with which an organism captures and consumes its prey in an ecosystem. Coupled with the kill rate, the predation rate drives the population dynamics of predation. This statistic is related to Predator–prey dynamics and may be influenced by several factors. In order for predation to occur, a predator and its prey must encounter one another. A low concentration of prey decreases the likelihood of such encounters. The prey encounter rate is determined by the abundance of organisms and a predator’s ability to locate its prey. Covering more territory increases the likelihood that a predator will meet its prey. In areas of low prey density, predators are adapted to be more motile, engage in filter feeding, or use attractants such as chemical lures. If predation increased simply with prey concentration, the relationship would be linear until a limit is reached. This scenario is represented by Holling's type I functional response, which is rarely observed in nature. Several factors affect this relationship, including handling time (the time required for a predator to consume its prey), selective feeding behaviors, and learning. In contrast, Holling's type II and type III functional responses account for the time


id: prehensility-20260505-0
file: data/en.wikipedia.org/wiki/Prehensility-0.md
category: reference
title: Prehensility
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Prehensility
date_saved: 2026-05-05T07:16:29.527669+00:00
instance: kb-cron
parent: prehensility-20260505-0
summary:
Prehensility is the quality of an appendage or organ that has adapted for grasping or holding. The word is derived from the Latin term prehendere, meaning "to grasp". The ability to grasp is likely derived from a number of different origins. The most common are tree-climbing and the need to manipulate food. == Examples == Appendages that can become prehensile include: == Uses == Prehensility affords animals a great natural advantage in manipulating their environment for feeding, climbing, digging, and defense. It enables many animals, such as primates, to use tools to complete tasks that would otherwise be impossible without highly specialized anatomy. For example, chimpanzees have the ability to use sticks to obtain termites and grubs in a manner similar to human fishing. However, not all prehensile organs are applied to tool use; the giraffe tongue, for instance, is instead used in feeding and self-cleaning. == See also == Robot end effector == References ==


id: proteostasis-20260505-0
file: data/en.wikipedia.org/wiki/Proteostasis-0.md
category: reference
title: Proteostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Proteostasis
date_saved: 2026-05-05T07:16:30.910694+00:00
instance: kb-cron
parent: proteostasis-20260505-0
summary:
Proteostasis is the dynamic regulation of a balanced, functional proteome. The proteostasis network includes competing and integrated biological pathways within cells that control the biogenesis, folding, trafficking, and degradation of proteins present within and outside the cell. Loss of proteostasis is central to understanding the cause of diseases associated with excessive protein misfolding and degradation leading to loss-of-function phenotypes, as well as aggregation-associated degenerative disorders. Therapeutic restoration of proteostasis may treat or resolve these pathologies. Cellular proteostasis is key to ensuring successful development, healthy aging, resistance to environmental stresses, and to minimize homeostatic perturbations from pathogens such as viruses. Cellular mechanisms for maintaining proteostasis include regulated protein translation, chaperone assisted protein folding, and protein degradation pathways. Adjusting each of these mechanisms based on the need for specific proteins is essential to maintain all cellular functions relying on a correctly folded proteome. == Mechanisms of proteostasis == === The roles of the ribosome in proteostasis === One of the first points of regulation for proteostasis is during translation. This regulation is accomplished via the structure of the ribosome, a complex central to translation. Its characteristics shape the way the protein folds, and influence the protein's future interactions. The synthesis of a


id: proteostasis-20260505-1
file: data/en.wikipedia.org/wiki/Proteostasis-1.md
category: reference
title: Proteostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Proteostasis
date_saved: 2026-05-05T07:16:30.910694+00:00
instance: kb-cron
parent: proteostasis-20260505-0
summary:
=== Cytosolic heat shock response === The cytosolic heat shock response (HSR) is mainly mediated by the transcription factor family HSF (heat shock family). HSF is constitutively bound by Hsp90. Upon a proteotoxic stimulus Hsp90 is recruited away from HSF, which can then bind to heat response elements in the DNA and upregulate gene expression of proteins involved in the maintenance of proteostasis. === ER unfolded protein response === The unfolded protein response (UPR) in the ER is activated by imbalances of unfolded proteins inside the ER and the proteins mediating protein homeostasis. Different "detectors" - such as IRE1, ATF6 and PERK - can recognize misfolded proteins in the ER and mediate transcriptional responses which help alleviate the effects of ER stress. === Mitochondrial unfolded protein response === The mitochondrial unfolded protein response detects imbalances in protein stoichiometry of mitochondrial proteins and misfolded proteins. The expression of mitochondrial chaperones is upregulated by the activation of the transcription factors ATF1 and/or DVE-1 with UBL5. === Systemic stress signaling === Stress responses can also be triggered in a non-cell autonomous fashion by intercellular communication. The stress that is sensed in one tissue could thereby be communicated to other tissues to protect the


id: proteostasis-20260505-2
file: data/en.wikipedia.org/wiki/Proteostasis-2.md
category: reference
title: Proteostasis
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Proteostasis
date_saved: 2026-05-05T07:16:30.910694+00:00
instance: kb-cron
parent: proteostasis-20260505-0
summary:
=== Pharmacologic intervention in proteostasis === There are two main approaches that have been used for therapeutic development targeting the proteostatic network: pharmacologic chaperones and proteostasis regulators. The principle behind designing pharmacologic chaperones for intervention in diseases of proteostasis is to design small molecules that stabilize proteins exhibiting borderline stability. Previously, this approach has been used to target and stabilize G-protein coupled receptors, neurotransmitter receptors, glycosidases, lysosomal storage proteins, and the mutant CFTR protein that causes cystic fibrosis and transthyretin, which can misfiled and aggregate leading to amyloidoses. Vertex Pharmaceuticals and Pfizer sell regulatory agency approved pharmacologic chaperones for ameliorating cystic fibrosis and the transthyretin amyloidoses, respectively. Amicus sells a regulatory agency approved pharmacologic chaperone for Fabry disease–a lysosomal storage disease. The principle behind proteostasis regulators is different. These molecules alter the biology of protein folding and/or degradation by altering the stoichiometry of the proteostasis network components in a given sub cellular compartment. For example, some proteostasis regulators initiate stress responsive signaling, such as the unfolded protein response, which transcriptionally reprograms the endoplasmic reticulum proteostasis network. It has been suggested that this approach could even be applied prophylactically, such as upregulating certain protective pathways before experiencing an anticipated severe cellular


id: psammon-20260505-0
file: data/en.wikipedia.org/wiki/Psammon-0.md
category: reference
title: Psammon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Psammon
date_saved: 2026-05-05T07:16:32.210054+00:00
instance: kb-cron
parent: psammon-20260505-0
summary:
Psammon (from Greek "psammos", "sand") is an ecological community of organisms inhabiting coastal sand. It consists of biota buried in moist sediments. Psammon is also sometimes considered a part of benthos due to its near-bottom distribution. Psammon term is commonly used to refer to freshwater reservoirs such as lakes. == See also == Epipsammon == References ==


id: psammophyte-20260505-0
file: data/en.wikipedia.org/wiki/Psammophyte-0.md
category: reference
title: Psammophyte
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Psammophyte
date_saved: 2026-05-05T07:16:33.528329+00:00
instance: kb-cron
parent: psammophyte-20260505-0
summary:
A psammophyte is a plant that grows in sandy and often unstable soils. Psammophytes are commonly found growing on beaches, deserts, and sand dunes. Because they thrive in these challenging or inhospitable habitats, psammophytes are considered extremophiles, and are further classified as a type of psammophile. == Etymology == The word "psammophyte" consists of two Greek roots, psamm-, meaning "sand", and -phyte, meaning "plant". The term "psammophyte" first entered English in the early twentieth century via German botanical terminology. == Description == Psammophytes are found in many different plant families, so may not share specific morphological or phytochemical traits. They also come in a variety of plant life-forms, including annual ephemerals, perennials, subshrubs, hemicryptophytes, and many others. What the many diverse psammophytes have in common is a resilience to harsh or rapidly fluctuating environmental factors, such as shifting soils, strong winds, intense sunlight exposure, or saltwater exposure, depending on the habitat. Psammophytes often have specialized traits, such as unusually tenacious or resilient roots that enable them to anchor and thrive despite various environmental stressors. Those growing in arid regions have evolved highly efficient physiological mechanisms that enable them to survive despite limited water availability, similar to those in other xerophytes.


id: pyrrolizidine-alkaloid-sequestration-20260505-0
file: data/en.wikipedia.org/wiki/Pyrrolizidine_alkaloid_sequestration-0.md
category: reference
title: Pyrrolizidine alkaloid sequestration
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Pyrrolizidine_alkaloid_sequestration
date_saved: 2026-05-05T07:16:34.807727+00:00
instance: kb-cron
parent: pyrrolizidine-alkaloid-sequestration-20260505-0
summary:
Pyrrolizidine alkaloid sequestration by insects is a strategy to facilitate defense and mating. Various species of insects have been known to use molecular compounds from plants for their own defense and even as their pheromones or precursors to their pheromones. A few Lepidoptera have been found to sequester chemicals from plants which they retain throughout their life and some members of Erebidae are examples of this phenomenon. Starting in the mid-twentieth century researchers investigated various members of Arctiidae, and how these insects sequester pyrrolizidine alkaloids (PAs) during their life stages, and use these chemicals as adults for pheromones or pheromone precursors. PAs are also used by members of the Arctiidae for defense against predators throughout the life of the insect. == Overview == Pyrrolizidine alkaloids are a group of chemicals produced by plants as secondary metabolites, all of which contain a pyrrolizidine nucleus. This nucleus is made up of two pyrrole rings bonded by one carbon and one nitrogen. There are two forms in which PAs can exist and will readily interchange between: a pro-toxic free base form, also called a tertiary amine, or in a non-toxic form of N-oxide. Researchers have collected data that strongly suggests that PAs can


id: range-state-20260505-0
file: data/en.wikipedia.org/wiki/Range_state-0.md
category: reference
title: Range state
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Range_state
date_saved: 2026-05-05T07:16:36.174449+00:00
instance: kb-cron
parent: range-state-20260505-0
summary:
Range state is a term generally used in zoogeography and conservation biology to refer to any nation that exercises jurisdiction over any part of a range which a particular species, taxon or biotope inhabits, or crosses or overflies at any time on its normal migration route. The term is often expanded to also include, particularly in international waters, any nation with vessels flying their flag that engage in exploitation (e.g. hunting, fishing, capturing) of that species. Countries in which a species occurs only as a vagrant or ‘accidental’ visitor outside of its normal range or migration route are not usually considered range states. Because governmental conservation policy is often formulated on a national scale, and because in most countries, both governmental and private conservation organisations are also organised at the national level, the range state concept is often used by international conservation organizations in formulating their conservation and campaigning policy. An example of one such organization is the Convention on the Conservation of Migratory Species of Wild Animals (CMS, or the “Bonn Convention”). It is a multilateral treaty focusing on the conservation of critically endangered and threatened migratory species, their habitats and their migration routes. Because such habitats and/or migration


id: redundancy-principle-biology-20260505-0
file: data/en.wikipedia.org/wiki/Redundancy_principle_(biology)-0.md
category: reference
title: Redundancy principle (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Redundancy_principle_(biology)
date_saved: 2026-05-05T07:16:37.452192+00:00
instance: kb-cron
parent: redundancy-principle-biology-20260505-0
summary:
The redundancy principle in biology expresses the need of many copies of the same entity (cells, molecules, ions) to fulfill a biological function. Examples are numerous: disproportionate numbers of spermatozoa during fertilization compared to one egg, large number of neurotransmitters released during neuronal communication compared to the number of receptors, large numbers of released calcium ions during transient in cells, and many more in molecular and cellular transduction or gene activation and cell signaling. This redundancy is particularly relevant when the sites of activation are physically separated from the initial position of the molecular messengers. The redundancy is often generated for the purpose of resolving the time constraint of fast-activating pathways. It can be expressed in terms of the theory of extreme statistics to determine its laws and quantify how the shortest paths are selected. The main goal is to estimate these large numbers from physical principles and mathematical derivations. When a large distance separates the source and the target (a small activation site), the redundancy principle explains that this geometrical gap can be compensated by large number. Had nature used less copies than normal, activation would have taken a much longer time, as finding a small target by chance


id: redundancy-principle-biology-20260505-1
file: data/en.wikipedia.org/wiki/Redundancy_principle_(biology)-1.md
category: reference
title: Redundancy principle (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Redundancy_principle_(biology)
date_saved: 2026-05-05T07:16:37.452192+00:00
instance: kb-cron
parent: redundancy-principle-biology-20260505-0
summary:
where the boundary ∂ Ω {\displaystyle \partial \Omega } contains NR binding sites ∂ Ω i ⊂ ∂ Ω {\displaystyle \partial \Omega _{i}\subset \partial \Omega } ( ∂ Ω a = ⋃ i = 1 N R ∂ Ω i , ∂ Ω r = ∂ Ω − ∂ Ω a {\displaystyle \partial \Omega _{a}=\bigcup \limits _{i=1}^{N_{R}}\partial \Omega _{i},\ \partial \Omega _{r}=\partial \Omega -\partial \Omega _{a}} ). The single particle survival probability is Pr { t 1 > t } = ∫ Ω p ( x , t ) d x , {\displaystyle \Pr\{t_{1}>t\}=\int \limits _{\Omega }p(x,t)dx,} so that Pr { τ 1 = t } = d d t Pr { τ 1 < t } = N ( Pr { t 1 > t } ) N − 1 Pr { t 1 = t } , {\displaystyle \Pr\{\tau ^{1}=t\}={\frac {d}{dt}}\Pr\{\tau ^{1}<t\}=N(\Pr\{t_{1}>t\})^{N-1}\Pr \limits \{t_{1}=t\},} where Pr { t 1 = t } = ∮ ∂ Ω a ∂ p ( x , t ) ∂ n d S x {\displaystyle \Pr\{t_{1}=t\}={\oint _{\partial \Omega _{a}}}{\frac {\partial p(x,t)}{\partial n}}\,dS_{x}} and Pr { t 1 = t } = N R ∮ ∂ Ω 1 ∂ p ( x , t


id: redundancy-principle-biology-20260505-2
file: data/en.wikipedia.org/wiki/Redundancy_principle_(biology)-2.md
category: reference
title: Redundancy principle (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Redundancy_principle_(biology)
date_saved: 2026-05-05T07:16:37.452192+00:00
instance: kb-cron
parent: redundancy-principle-biology-20260505-0
summary:
Pr { t 1 > t | y } = ∫ 0 a p ( x , t | y ) d x d s ∼ 1 − max 2 t π [ e − y 2 / 4 t y , e − ( a − y ) 2 / 4 t a − y ] as t → 0 {\displaystyle \Pr\{t_{1}>t\,|\,y\}=\int \limits \limits _{0}^{a}p(x,t\,|\,y)\,dxds\sim 1-\max {\frac {2{\sqrt {t}}}{\sqrt {\pi }}}\left[{\frac {e^{-y^{2}/4t}}{y}},{\frac {e^{-(a-y)^{2}/4t}}{a-y}}\right]\quad {\mbox{as}}\ t\to 0} , where the maximum occurs at δ = {\displaystyle \delta =} min[y,a-y] for 0<y<a (the shortest ray from y to the boundary). All other integrals can be computed explicitly, leading to τ ¯ 1 = ∫ 0 ∞ [ Pr { t 1 > t } ] N d t ≈ ∫ 0 ∞ exp ⁡ { N ln ⁡ ( 1 − 8 t δ π e − δ 2 / 16 t ) } d t ≈ δ 2 16 D ln ⁡ 2 N π for N ≫ 1. {\displaystyle {\bar {\tau }}^{1}=\int \limits \limits _{0}^{\infty }\left[\Pr\{t_{1}>t\}\right]^{N}dt\approx \int \limits \limits _{0}^{\infty }\exp \left\{N\ln \left(1-{\frac {8{\sqrt {t}}}{\delta {\sqrt {\pi }}}}e^{-\delta ^{2}/16t}\right)\right\}dt\approx {\frac {\delta ^{2}}{16D\ln {\frac {2N}{\sqrt {\pi }}}}}\quad {\mbox{for}}\ N\gg 1.}


id: redundancy-principle-biology-20260505-3
file: data/en.wikipedia.org/wiki/Redundancy_principle_(biology)-3.md
category: reference
title: Redundancy principle (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Redundancy_principle_(biology)
date_saved: 2026-05-05T07:16:37.452192+00:00
instance: kb-cron
parent: redundancy-principle-biology-20260505-0
summary:
⟨ τ ( n ) ⟩ = ∫ 0 ∞ exp ⁡ { n log ⁡ ∫ Ω p ( x , t | y ) d x } d t = ∫ 0 ∞ τ σ P r { Path σ ∈ S n ( y ) , τ σ = t } d t , {\displaystyle \langle \tau ^{(n)}\rangle =\int \limits \limits _{0}^{\infty }\exp \left\{n\log \int \limits _{\Omega }p(x,t|y)\,dx\right\}dt=\int _{0}^{\infty }\tau _{\sigma }Pr\{{\hbox{ Path }}\sigma \in S_{n}(y),\tau _{\sigma }=t\}dt,} where S n ( y ) {\displaystyle S_{n}(y)} is the ensemble of shortest paths selected among n Brownian trajectories, starting at point y and exiting between time t and t+dt from the domain Ω {\displaystyle \Omega } . The probability P r { Path σ ∈ S n } {\displaystyle Pr\{{\hbox{ Path }}\sigma \in S_{n}\}} is used to show that the empirical stochastic trajectories of S n {\displaystyle S_{n}} concentrate near the shortest paths starting from y and ending at the small absorbing window ∂ Ω a {\displaystyle \partial \Omega _{a}} , under the condition that ϵ = | ∂ Ω a | | ∂ Ω | ≪ 1 {\displaystyle \epsilon ={\frac {|\partial \Omega _{a}|}{|\partial \Omega |}}\ll 1} .


id: redundancy-principle-biology-20260505-4
file: data/en.wikipedia.org/wiki/Redundancy_principle_(biology)-4.md
category: reference
title: Redundancy principle (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Redundancy_principle_(biology)
date_saved: 2026-05-05T07:16:37.452192+00:00
instance: kb-cron
parent: redundancy-principle-biology-20260505-0
summary:
where the integral is taken over all paths starting at y(0) and exiting at time m Δ t {\displaystyle m\Delta t} . This formula suggests that when n is large, only the paths that minimize the integrant will contribute. For large n, this formula suggests that paths that will contribute the most are the ones that will minimize the exponent, which allows selecting the paths for which the energy functional is minimal, that is E = min X ∈ P t ∫ 0 T x ˙ 2 d s , {\displaystyle E=\min _{X\in {\mathcal {P}}_{t}}\int \limits _{0}^{T}{\dot {x}}^{2}ds,} where the integration is taken over the ensemble of regular paths P t {\displaystyle {\mathcal {P}}_{t}} inside Ω {\displaystyle \Omega } starting at y and exiting in ∂ Ω a {\displaystyle \partial \Omega _{a}} , defined as P T = { P ( 0 ) = y , P ( T ) ∈ ∂ Ω a and P ( s ) ∈ Ω and 0 ≤ s ≤ T } . {\displaystyle {\mathcal {P}}_{T}=\{P(0)=y,P(T)\in \partial \Omega _{a}{\hbox{ and }}P(s)\in \Omega {\hbox{ and }}0\leq s\leq T\}.} This formal argument shows that the random paths associated to the fastest exit time are concentrated near


id: reproductive-interference-20260505-0
file: data/en.wikipedia.org/wiki/Reproductive_interference-0.md
category: reference
title: Reproductive interference
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reproductive_interference
date_saved: 2026-05-05T07:16:39.962893+00:00
instance: kb-cron
parent: reproductive-interference-20260505-0
summary:
Reproductive interference is the interaction between individuals of different species during mate acquisition that leads to a reduction of fitness in one or more of the individuals involved. The interactions occur when individuals make mistakes or are unable to recognise their own species, labelled as ‘incomplete species recognition'. Reproductive interference has been found within a variety of taxa, including insects, mammals, birds, amphibians, marine organisms, and plants. There are seven causes of reproductive interference, namely signal jamming, heterospecific rivalry, misdirected courtship, heterospecific mating attempts, erroneous female choice, heterospecific mating, and hybridisation. All types have fitness costs on the participating individuals, generally from a reduction in reproductive success, a waste of gametes, and the expenditure of energy and nutrients. These costs are variable and dependent on numerous factors, such as the cause of reproductive interference, the sex of the parent, and the species involved. Reproductive interference occurs between species that occupy the same habitat and can play a role in influencing the coexistence of these species. It differs from competition as reproductive interference does not occur due to a shared resource. Reproductive interference can have ecological consequences, such as through the segregation of species both spatially and temporally. It can also


id: reproductive-interference-20260505-1
file: data/en.wikipedia.org/wiki/Reproductive_interference-1.md
category: reference
title: Reproductive interference
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reproductive_interference
date_saved: 2026-05-05T07:16:39.962893+00:00
instance: kb-cron
parent: reproductive-interference-20260505-0
summary:
Auditory signalling in the gray treefrog (Hyla versicolor) and the Cope's gray treefrogs (Hyla chrysoscelis) – The success of reproduction is dependent on a female’s ability to correctly identify and respond to the advertisement call of a potential mate. At a breeding site with high densities of males, the male’s chorus may overlap with heterospecific calls, making it difficult for the female to successfully locate a mate. When the advertisement calls of the male gray treefrog and male Cope’s gray treefrog overlap, female gray treefrogs make mistakes and choose the heterospecific call. The amount of errors the female makes is dependent on the amount of overlap between signals. Female Cope’s gray treefrogs can better differentiate the signals and are only significantly affected when heterospecifics completely overlap conspecific male signals. However, female Cope’s gray treefrogs prefer conspecific male signals that have less overlap (i.e. less interference). Furthermore, females have longer response times to overlapped calls, where it takes longer for them to choose a mate. Signal jamming can affect both males and females as difficulties in identifying and locating a mate reduces their mating frequencies. Females may have more costs if they mate with a male of a lower quality, and


id: reproductive-interference-20260505-2
file: data/en.wikipedia.org/wiki/Reproductive_interference-2.md
category: reference
title: Reproductive interference
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reproductive_interference
date_saved: 2026-05-05T07:16:39.962893+00:00
instance: kb-cron
parent: reproductive-interference-20260505-0
summary:
Atlantic salmon (Salmo salar) – Atlantic salmon that were once native to Lake Ontario were reintroduced to the lake to study their spawning interactions with other species of fish, including the chinook salmon, coho salmon, and brown trout. Chinook salmon interacted with Atlantic salmon the most, where male chinooks attempted to court female Atlantic salmon. Male chinooks also chased away, and in some interactions, behaved aggressively towards other Atlantic salmon that approached female Atlantic salmon. A male brown trout was also observed to court a female Atlantic salmon. Misdirected courtship towards the Atlantic salmon can cause problems in waters that the Atlantic salmon currently occupy, and towards conservation efforts to reintroduce the Atlantic salmon to Lake Ontario. Implications of misdirected courtship on the Atlantic salmon can cause the delay or prevention of spawning, and the hybridisation of the Atlantic salmon with other species. === Heterospecific mating attempts === Heterospecific mating attempts occur when males attempt to mate with females of a different species, regardless of whether courtship occurs. During each mating attempt, sperm transfer may or may not occur. Both sexes have costs when a heterospecific attempts to mate. Costs associated with heterospecific mating attempts include wasted energy, time, and


id: reproductive-interference-20260505-3
file: data/en.wikipedia.org/wiki/Reproductive_interference-3.md
category: reference
title: Reproductive interference
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Reproductive_interference
date_saved: 2026-05-05T07:16:39.962893+00:00
instance: kb-cron
parent: reproductive-interference-20260505-0
summary:
==== Examples ==== Spider mites – two closely related Panonychus mites: the Panonychus citri and Panonychus mori, are generally geographically segregated and on occasion co-exist. However, the co-existence is not stable as the Panonychus mori is eventually excluded. The exclusion is a result of reproductive interference and also due to the higher reproductive rate of the Panonychus citri. Heterospecific mating occurs between the two species which can produce infertile eggs or infertile hybrid females. Furthermore, females are not able to produce female offspring after mating with a heterospecific. In addition to the wastage of energy, time, and gametes, the inability to produce female offspring after heterospecific mating skews the sex ratio of the co-existing populations. The high costs associated with heterospecific mating along with the higher reproductive rate of the Panonychus citri lead to the displacement of the Panonychus mori. Black-legged meadow katydid (Orchelimum nigripes) and the handsome meadow katydid (Orchelimum pulchellum) – The two closely related species of katydid have the same habitat preferences and co-exist along the Potomac River. Females of both species that mate heterospecifically have a large reduction in fecundity compared to conspecific pairings. Heterospecific mating either produces no eggs or male hybrids that may be


id: retinalophototroph-20260505-0
file: data/en.wikipedia.org/wiki/Retinalophototroph-0.md
category: reference
title: Retinalophototroph
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Retinalophototroph
date_saved: 2026-05-05T07:16:41.252337+00:00
instance: kb-cron
parent: retinalophototroph-20260505-0
summary:
A retinalophototroph is one of two different types of phototrophs, and are named for retinal-binding proteins (microbial rhodopsins) they utilize for cell signaling and converting light into energy. Like all phototrophs, retinalophototrophs absorb photons to initiate their cellular processes. In contrast with chlorophototrophs, retinalophototrophs do not use chlorophyll or an electron transport chain to power their chemical reactions. This means retinalophototrophs are incapable of traditional carbon fixation, a fundamental photosynthetic process that transforms inorganic carbon (carbon contained in molecular compounds like carbon dioxide) into organic compounds. For this reason, experts consider them to be less efficient than their chlorophyll-using counterparts, chlorophototrophs. == Energy conversion == Retinalophototrophs achieve adequate energy conversion via a proton-motive force. In retinalophototrophs, proton-motive force is generated from rhodopsin-like proteins, primarily bacteriorhodopsin and proteorhodopsin, acting as proton pumps along a cellular membrane. To capture photons needed for activating a protein pump, retinalophototrophs employ organic pigments known as carotenoids, namely beta-carotenoids. Beta-carotenoids present in retinalophototrophs are unusual candidates for energy conversion, but they possess high Vitamin-A activity necessary for retinaldehyde, or retinal, formation. Retinal, a chromophore molecule configured from Vitamin A, is formed when bonds between carotenoids are disrupted in a process called cleavage. Due to its acute


id: rimose-20260505-0
file: data/en.wikipedia.org/wiki/Rimose-0.md
category: reference
title: Rimose
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Rimose
date_saved: 2026-05-05T07:16:42.501491+00:00
instance: kb-cron
parent: rimose-20260505-0
summary:
Rimose is an adjective used to describe a surface that is cracked or fissured. The term is often used in describing crustose lichens. A rimose surface of a lichen is sometimes contrasted to the surface being areolate. Areolate is an extreme form of being rimose, where the cracks or fissures are so deep that they create island-like pieces called areoles, which look the "islands" of mud on the surface of a dry lake bed. Rimose and areolate are contrasted with being verrucose, or "warty". Verrucose surfaces have warty bumps which are distinct, but not separated by cracks. In mycology the term describes mushrooms whose caps crack in a radial pattern, as commonly found in the genera Inocybe and Inosperma. == References ==


id: runt-20260505-0
file: data/en.wikipedia.org/wiki/Runt-0.md
category: reference
title: Runt
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Runt
date_saved: 2026-05-05T07:16:43.749383+00:00
instance: kb-cron
parent: runt-20260505-0
summary:
A runt is an animal that is unusually small for its species. In veterinary medicine, a runt may also be described using terms such as low-birth weight, intrauterine growth restriction, and small for gestational age. An animal may be defined as small for gestational age (SGA) depending on different criteria, such as size in comparison to littermates', as percent of maternal body weight, as a specific neonate weight threshold for the breed or species, and as different body proportions displayed by runts. Runts face many challenges in comparison to their normal birth weight peers - they are more likely to contract diseases, and die in the neonatal period, have lower glycogen stores, have developmental delays, insulin resistance, hypothermia, and low blood pressure. Runts are also associated with economic losses in farm animals - SGA adult cows give smaller milk yields and have infertility, intrauterine growth restricted (IUGR) piglets have modifications in their muscle tissue that may affect the taste of their meat, adult IUGR sows have smaller litter sizes and lower birth weight piglets in their litters and adult low birth weight ewes may have poorer quality fleeces. == Causes == SGA has been best studied in pigs, both due


id: smash-and-grab-biology-20260505-0
file: data/en.wikipedia.org/wiki/Smash_and_Grab_(biology)-0.md
category: reference
title: Smash and Grab (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Smash_and_Grab_(biology)
date_saved: 2026-05-05T07:16:44.953153+00:00
instance: kb-cron
parent: smash-and-grab-biology-20260505-0
summary:
Smash and Grab is the name given to a technique developed by Charles S. Hoffman and Fred Winston used in molecular biology to rescue plasmids from yeast transformants into Escherichia coli, also known as E. coli, in order to amplify and purify them. In addition, it can be used to prepare yeast genomic DNA (and DNA from tissue samples) for Southern blot analyses or polymerase chain reaction (PCR). == References ==


id: sociome-20260505-0
file: data/en.wikipedia.org/wiki/Sociome-0.md
category: reference
title: Sociome
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Sociome
date_saved: 2026-05-05T07:16:46.170901+00:00
instance: kb-cron
parent: sociome-20260505-0
summary:
The Sociome is a concept used by scientists in Biology and Sociology referring to the dimensions of existence that are social. The term is also an indication of the convergence of systems biology and the study of society as a complex system that has begun to occur among early 21st Century scientists. Just as the phenome is typically thought of as the set of expressed phenotypes of an organism, the sociome can be thought of as the set of observed characteristics of societies. For example, while all societies consisting of humans might be thought of as having the potential to become egalitarian social democracies, not all observed societies are egalitarian or social democracies. Thus, the sociome can also be thought of indirectly as an ideal type of the unrealized potential of any given organization of social beings. == Origin of term == The first known usage of the term sociome was in 2001 by Daichi Kamiyama. The term has also been utilized by sociologist Adam Thomas Perzynski. The two scientists differ in their usage. Kamiyama's study describes a new scientific "era of the sociome (Sociology[+ome])" characterized by the study of the social activities of molecules. This usage is an anthropomorphism


id: storage-organ-20260505-0
file: data/en.wikipedia.org/wiki/Storage_organ-0.md
category: reference
title: Storage organ
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Storage_organ
date_saved: 2026-05-05T07:16:48.570582+00:00
instance: kb-cron
parent: storage-organ-20260505-0
summary:
A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water. Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have an underground storage organ are called geophytes in the Raunkiær plant life-form classification system. Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions (such as cold, excessive heat, lack of light or drought). == Relationship to perennating organ == Storage organs may act as perennating organs ('perennating' as in perennial, meaning "through the year", used in the sense of continuing beyond the year and in due course lasting for multiple years). These are used by plants to survive adverse periods in the plant's life-cycle (e.g. caused by cold, excessive heat, lack of light or drought). During these periods, parts of the plant die and then when conditions become favourable again, re-growth occurs from buds in the perennating organs. For example, geophytes growing in woodland under deciduous trees (e.g. bluebells, trilliums) die back to underground storage organs during summer when tree leaf cover restricts light and water is less available. However, perennating organs


id: substrate-biology-20260505-0
file: data/en.wikipedia.org/wiki/Substrate_(biology)-0.md
category: reference
title: Substrate (biology)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Substrate_(biology)
date_saved: 2026-05-05T07:16:49.725303+00:00
instance: kb-cron
parent: substrate-biology-20260505-0
summary:
In biology, a substrate is the surface on which an organism (such as a plant, fungus, or animal) lives. A substrate can include biotic or abiotic materials and animals. For example, encrusting algae that lives on a rock (its substrate) can be itself a substrate for an animal that lives on top of the algae. Inert substrates are used as growing support materials in the hydroponic cultivation of plants. In biology substrates are often activated by the nanoscopic process of substrate presentation. == In agriculture and horticulture == Cellulose substrate Expanded clay aggregate (LECA) Rock wool Potting soil Soil == In animal biotechnology == === Requirements for animal cell and tissue culture === Requirements for animal cell and tissue culture are the same as described for plant cell, tissue and organ culture (In Vitro Culture Techniques: The Biotechnological Principles). Desirable requirements are (i) air conditioning of a room, (ii) hot room with temperature recorder, (iii) microscope room for carrying out microscopic work where different types of microscopes should be installed, (iv) dark room, (v) service room, (vi) sterilization room for sterilization of glassware and culture media, and (vii) preparation room for media preparation, etc. In addition the storage areas should


id: subvariety-botany-20260505-0
file: data/en.wikipedia.org/wiki/Subvariety_(botany)-0.md
category: reference
title: Subvariety (botany)
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Subvariety_(botany)
date_saved: 2026-05-05T07:16:51.293257+00:00
instance: kb-cron
parent: subvariety-botany-20260505-0
summary:
A subvariety (Latin: subvarietas) in botanical nomenclature is a taxonomic rank. They are rarely used to classify organisms. == Plant taxonomy == Subvariety is ranked: below that of variety (varietas) above that of form (forma). Subvariety is an infraspecific taxon. === Name === Its name consists of three parts: a genus name (genera) a specific epithet (species) an infraspecific epithet (subvariety) To indicate the subvariety rank, the abbreviation "subvar." is put before the infraspecific epithet. == References ==


id: suctorial-20260505-0
file: data/en.wikipedia.org/wiki/Suctorial-0.md
category: reference
title: Suctorial
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Suctorial
date_saved: 2026-05-05T07:16:52.681651+00:00
instance: kb-cron
parent: suctorial-20260505-0
summary:
Suctorial pertains to the adaptation for sucking or suction, as possessed by marine parasites such as the Cookiecutter shark, specifically in a specialised lip organ enabling attachment to the host. Suctorial organs of a different form are possessed by the Solifugae arachnids, enabling the climbing of smooth, vertical surfaces. Another variation on the suctorial organ can be found as part of the glossa proboscis of Masarinae (pollen wasps), enabling nectar feeding from the deep and narrow corolla of flowers. == References ==


id: syngameon-20260505-0
file: data/en.wikipedia.org/wiki/Syngameon-0.md
category: reference
title: Syngameon
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Syngameon
date_saved: 2026-05-05T07:16:54.005494+00:00
instance: kb-cron
parent: syngameon-20260505-0
summary:
Syngameon refers to groups of taxa that frequently engage in natural hybridization and lack strong reproductive barriers that prevent interbreeding. Syngameons are more common in plants than animals, with approximately 25% of plant species and 10% of animal species producing natural hybrids. The most well known syngameons include irises of the California Pacific Coast and white oaks of the Eastern United States. Hybridization within a syngameon is typically not equally distributed among species and few species often dominate patterns of hybridization. The term syngameon comes from the root word syngamy coined by Edward Bagnall Poulton to define groups that freely interbreed. He also coined the word asyngamy referring to groups that do not freely interbreed (with the substantive noun forms Syngamy and Asyngamy). The term syngameon was first used by Johannes Paulus Lotsy, who used it to describe a habitually interbreeding community that was reproductively isolated from other habitually interbreeding communities. Syngameon was used interchangeably with the term species to describe groups of closely related individuals that interbreed to varying degrees. A more specific definition of syngameon has been given to groups of taxa that frequently engage in natural hybridization and lack strong morphological differences that could be used to


id: temperature-sensitive-mutant-20260505-0
file: data/en.wikipedia.org/wiki/Temperature-sensitive_mutant-0.md
category: reference
title: Temperature-sensitive mutant
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Temperature-sensitive_mutant
date_saved: 2026-05-05T07:16:55.194576+00:00
instance: kb-cron
parent: temperature-sensitive-mutant-20260505-0
summary:
Temperature-sensitive mutations are variants of genes that allow the organism to function normally at low temperatures but alter its function at higher temperatures. Cold-sensitive mutants are variants of genes that allow normal function of the organism at higher temperatures but altered function at low temperatures. == Mechanism == Most temperature-sensitive mutations affect proteins, and cause loss of protein function at the non-permissive temperature. The permissive temperature is one at which the protein typically can fold properly or remain properly folded. At higher temperatures, the protein is unstable and ceases to function properly. These mutations are usually recessive in diploid organisms. Temperature -sensitive mutations arrange a reversible mechanism and can reduce particular gene products at varying stages of growth, which is easily done by changing the temperature of growth. == Permissive temperature == The permissive temperature is the temperature at which a temperature-sensitive mutation gene product takes on a normal, functional phenotype. When a temperature-sensitive mutant is grown in a permissive condition, the mutant gene product behaves normally (meaning that the phenotype is not observed), even if there is a mutant allele present. This results in the survival of the cell or organism,as if it were a wild type strain. In


id: temperature-sensitive-mutant-20260505-1
file: data/en.wikipedia.org/wiki/Temperature-sensitive_mutant-1.md
category: reference
title: Temperature-sensitive mutant
tags: science, encyclopedia
source_url: https://en.wikipedia.org/wiki/Temperature-sensitive_mutant
date_saved: 2026-05-05T07:16:55.194576+00:00
instance: kb-cron
parent: temperature-sensitive-mutant-20260505-0
summary:
== Evolutionary Effects == Temperature is an environmental factor that influences the evolution of organisms by shaping their genetic variation, physiological traits, adaptations, and survivability. As global temperatures increase due to climate change, species have to adapt to these changes through mutations that affect protein function, such as temperature sensitive mutations. Specifically, higher temperatures can increase mutation rates, alter the stability of proteins, and influence natural selection. These factors can lead to evolutionary changes in populations over time. However, when adapting to these higher temperatures, organisms often experience trade-offs, which are compromises where gaining an advantage in one trait leads to a disadvantage in another. Higher temperatures can directly influence mutation rates by increasing the rate of spontaneous mutations leading to more errors during DNA replication or increased exposure to mutagens. Studies have shown that these effects are potentially due to enhanced metabolic rates. More specifically, a study involving Daphnia pulex found that spontaneous mutations had varied fitness effects under different thermal conditions, which suggests that temperature plays a role in shaping mutational impacts. In addition, this heightened mutation rate provides a broader range of genetic diversity for natural selection to act upon, allowing populations to adapt more rapidly. However,


