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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| History of paleontology | 9/10 | https://en.wikipedia.org/wiki/History_of_paleontology | reference | science, encyclopedia | 2026-05-05T04:00:05.779726+00:00 | kb-cron |
Throughout the 20th century new fossil finds continued to contribute to understanding the paths taken by evolution. Examples include major taxonomic transitions such as finds in Greenland, starting in the 1930s (with more major finds in the 1980s), of fossils illustrating the evolution of tetrapods from fish, and fossils in China during the 1990s that shed light on the dinosaur-bird relationship. Other events that have attracted considerable attention have included the discovery of a series of fossils in Pakistan that have shed light on whale evolution, and most famously of all a series of finds throughout the 20th century in Africa (starting with Taung child in 1924) and elsewhere have helped illuminate the course of human evolution. Increasingly, at the end of the 20th century, the results of paleontology and molecular biology were being brought together to reveal detailed phylogenetic trees. The results of paleontology have also contributed to the development of evolutionary theory. In 1944 George Gaylord Simpson published Tempo and Mode in Evolution, which used quantitative analysis to show that the fossil record was consistent with the branching, non-directional, patterns predicted by the advocates of evolution driven by natural selection and genetic drift rather than the linear trends predicted by earlier advocates of neo-Lamarckism and orthogenesis. This integrated paleontology into the modern evolutionary synthesis. In 1972 Niles Eldredge and Stephen Jay Gould used fossil evidence to advocate the theory of punctuated equilibrium, which maintains that evolution is characterized by long periods of relative stasis and much shorter periods of relatively rapid change.
=== Cambrian explosion ===
One area of paleontology that has seen a lot of activity during the 1980s, 1990s, and beyond is the study of the Cambrian explosion during which many of the various phyla of animals with their distinctive body plans first appear. The well-known Burgess Shale Cambrian fossil site was found in 1909 by Charles Doolittle Walcott, and another important site in Chengjiang China was found in 1912. However, new analysis in the 1980s by Harry B. Whittington, Derek Briggs, Simon Conway Morris and others sparked a renewed interest and a burst of activity including discovery of an important new fossil site, Sirius Passet, in Greenland, and the publication of a popular and controversial book, Wonderful Life by Stephen Jay Gould in 1989.
=== Pre-Cambrian fossils ===
Prior to 1950 there was no widely accepted fossil evidence of life before the Cambrian period. When Charles Darwin wrote The Origin of Species he acknowledged that the lack of any fossil evidence of life prior to the relatively complex animals of the Cambrian was a potential argument against the theory of evolution, but expressed the hope that such fossils would be found in the future. In the 1860s there were claims of the discovery of pre-Cambrian fossils, but these would later be shown not to have an organic origin. In the late 19th century Charles Doolittle Walcott would discover stromatolites and other fossil evidence of pre-Cambrian life, but at the time the organic origin of those fossils was also disputed. This would start to change in the 1950s with the discovery of more stromatolites along with microfossils of the bacteria that built them, and the publication of a series of papers by the Soviet scientist Boris Vasil'evich Timofeev announcing the discovery of microscopic fossil spores in pre-Cambrian sediments. A key breakthrough would come when Martin Glaessner would show that fossils of soft bodied animals discovered by Reginald Sprigg during the late 1940s in the Ediacaran hills of Australia were in fact pre-Cambrian not early Cambrian as Sprigg had originally believed, making the Ediacaran biota the oldest animals known. By the end of the 20th century, paleobiology had established that the history of life extended back at least 3.5 billion years.
== See also == History of biology History of evolutionary thought History of geology History of science List of fossil sites (with link directory) List of years in paleontology Taxonomy of commonly fossilised invertebrates Timeline of paleontology Treatise on Invertebrate Paleontology History of paleontology in the United States
== Notes ==