5.1 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Objections to evolution | 10/15 | https://en.wikipedia.org/wiki/Objections_to_evolution | reference | science, encyclopedia | 2026-05-05T03:08:38.113008+00:00 | kb-cron |
There's got to be a series of advantages all the way in the feather. If you can't think of one, then that's your problem not natural selection's problem... It's perfectly possible feathers began as fluffy extensions of reptilian scales to act as insulators... The earliest feathers might have been a different approach to hairiness among reptiles keeping warm.
Creationist arguments have been made such as "What use is half an eye?" and "What use is half a wing?". Research has confirmed that the natural evolution of the eye and other intricate organs is entirely feasible. Creationist claims have persisted that such complexity evolving without a designer is inconceivable and this objection to evolution has been refined in recent years as the more sophisticated irreducible complexity argument of the intelligent design movement, formulated by Michael Behe. Biochemist Michael Behe has argued that current evolutionary theory cannot account for certain complex structures, particularly in microbiology. On this basis, Behe argues that such structures were "purposely arranged by an intelligent agent". Irreducible complexity is the idea that certain biological systems cannot be broken down into their constituent parts and remain functional, and therefore that they could not have evolved naturally from less complex or complete systems. Whereas past arguments of this nature generally relied on macroscopic organs, Behe's primary examples of irreducible complexity have been cellular and biochemical in nature. He has argued that the components of systems such as the blood clotting cascade, the immune system, and the bacterial flagellum are so complex and interdependent that they could not have evolved from simpler systems. In the years since Behe proposed irreducible complexity, new developments and advances in biology such as an improved understanding of the evolution of flagella, have already undermined these arguments. The idea that seemingly irreducibly complex systems cannot evolve has been refuted through evolutionary mechanisms, such as exaptation (the adaptation of organs for entirely new functions) and the use of "scaffolding", which are initially necessary features of a system that later degenerate when they are no longer required. Potential evolutionary pathways have been provided for all of the systems Behe used as examples of irreducible complexity.
==== Cambrian explosion complexity argument ====
The Cambrian explosion was the relatively rapid appearance around 539 million years ago of most major animal phyla as demonstrated in the fossil record, and many more phyla now extinct. This was accompanied by major diversification of other organisms. Prior to the Cambrian explosion most organisms were simple, composed of individual cells occasionally organized into colonies. Over the following 70 or 80 million years the rate of diversification accelerated by an order of magnitude and the diversity of life began to resemble that of today, although they did not resemble the species of today. The basic problem with this is that natural selection calls for the slow accumulation of changes, where a new phylum would take longer than a new class which would take longer than a new order, which would take longer than a new family, which would take longer than a new genus would take longer than emergence of a new species but the apparent occurrence of high-level taxa without precedents is perhaps implying unusual evolutionary mechanisms. There is general consensus that many factors helped trigger the rise of new phyla, but there is no generally accepted consensus about the combination and the Cambrian explosion continues to be an area of controversy and research over why so rapid, why at the phylum level, why so many phyla then and none since, and even if the apparent fossil record is accurate. Some recent advances suggest that there is no clearly definable "Cambrian Explosion" event in the fossil record, but rather that there was a progression of transitional radiations starting with the Ediacaran period and continuing at a similar rate into the Cambrian. An example of opinions involving the commonly cited rise in oxygen Great Oxidation Event from biologist PZ Myers summarizes: "What it was was environmental changes, in particular the bioturbation revolution caused by the evolution of worms that released buried nutrients, and the steadily increasing oxygen content of the atmosphere that allowed those nutrients to fuel growth; ecological competition, or a kind of arms race, that gave a distinct selective advantage to novelties that allowed species to occupy new niches; and the evolution of developmental mechanisms that enabled multicellular organisms to generate new morphotypes readily." The increase in molecular oxygen (O2) also may have allowed the formation of the protective ozone layer (O3) that helps shield Earth from lethal UV radiation from the Sun.
=== Creation of information ===