Editing Extinction (section)

== History of scientific understanding ==
[[File:Tyrannosaurus-rex-Profile-steveoc86.png|thumb|''[[Tyrannosaurus]]'', one of the many extinct dinosaur genera. The cause of the [[Cretaceous–Paleogene extinction event]] is a subject of much debate amongst researchers.]]
[[File:Anoplotherium_1812_Skeleton_Sketch.jpg|thumb|Georges Cuvier's 1812 unpublished version of the skeletal reconstruction of ''[[Anoplotherium]] commune'' with muscles. Today, the [[Paleogene]] mammal is thought to have gone extinct from the [[Grande Coupure]] extinction event in western Europe.<ref>{{cite journal |last1=Hooker |first1=Jerry J. |last2=Collinson |first2=Margaret E. |author-link=Margaret Collinson |last3=Sille |first3=Nicholas P. |year=2004 |title=Eocene–Oligocene mammalian faunal turnover in the Hampshire Basin, UK: calibration to the global time scale and the major cooling event |journal=Journal of the Geological Society |volume=161 |issue=2 |pages=161–172 |doi=10.1144/0016-764903-091 |bibcode=2004JGSoc.161..161H |s2cid=140576090 |url=http://doc.rero.ch/record/13418/files/PAL_E228.pdf |access-date=25 August 2023 |archive-date=8 August 2023 |archive-url=https://web.archive.org/web/20230808072039/https://doc.rero.ch/record/13418/files/PAL_E228.pdf |url-status=live}}</ref>]]
[[File:Cuvier elephant jaw.jpg|thumb|[[Georges Cuvier]] compared fossil [[mammoth]] jaws to those of living elephants, concluding that they were distinct from any known living species.<ref name=":52">{{Cite web |url=http://evolution.berkeley.edu/evolibrary/article/history_08 |title=Extinctions: Georges Cuvier |website=evolution.berkeley.edu |access-date=2017-05-04 |archive-date=29 April 2017 |archive-url=https://web.archive.org/web/20170429200852/http://evolution.berkeley.edu/evolibrary/article/history_08 |url-status=live}}</ref>]]

For much of history, the modern understanding of extinction as the end of a [[species]] was incompatible with the prevailing worldview. Prior to the 19th century, much of Western society adhered to the belief that the world was created by God and as such was complete and perfect.<ref name=":02">{{Cite journal |last=Rowland |first=Stephen |date=2009 |title=Thomas Jefferson, extinction, and the evolving view of Earth history in the late eighteenth and early nineteenth centuries |url=http://memoirs.gsapubs.org/content/203/225.abstract |journal=GSA Memoirs |volume=203 |pages=225–246 |access-date=5 May 2017 |archive-date=1 September 2015 |archive-url=https://web.archive.org/web/20150901223048/http://memoirs.gsapubs.org/content/203/225.abstract |url-status=live}}</ref> This concept reached its heyday in the 1700s with the peak popularity of a theological concept called the [[great chain of being]], in which all life on earth, from the tiniest microorganism to God, is linked in a continuous chain.<ref name=":12">{{Cite book |url=http://www.gutenberg.org/files/33224/33224-h/33224-h.htm |title=The Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology |last=Lyells |first=Charles |publisher=Appleton Co |year=1854 |location=New York |access-date=5 May 2017 |archive-date=25 October 2016 |archive-url=https://web.archive.org/web/20161025005756/http://www.gutenberg.org/files/33224/33224-h/33224-h.htm |url-status=live}}</ref> The extinction of a species was impossible under this model, as it would create gaps or missing links in the chain and destroy the natural order.<ref name=":02" /><ref name=":12" /> [[Thomas Jefferson]] was a firm supporter of the great chain of being and an opponent of extinction,<ref name=":02" /><ref name=":32">{{cite web |last1=Bressan |first1=David |title=On the Extinction of Species |url=https://blogs.scientificamerican.com/history-of-geology/on-the-extinction-of-species/ |work=Scientific American Blog Network |date=17 August 2011 |access-date=5 May 2017 |archive-date=22 December 2017 |archive-url=https://web.archive.org/web/20171222105110/https://blogs.scientificamerican.com/history-of-geology/on-the-extinction-of-species/ |url-status=live}}{{self-published inline|date=February 2022}}</ref> famously denying the extinction of the [[woolly mammoth]] on the grounds that nature never allows a race of animals to become extinct.<ref name=":42">{{cite book |last1=Vidal |first1=Fernando |last2=Dias |first2=Nélia |title=Endangerment, Biodiversity and Culture |date=2015 |publisher=Routledge |isbn=978-1-317-53807-3}}{{page needed|date=February 2022}}</ref>

A series of fossils were discovered in the late 17th century that appeared unlike any living species. As a result, the scientific community embarked on a voyage of creative rationalization, seeking to understand what had happened to these species within a framework that did not account for total extinction. In October 1686, [[Robert Hooke]] presented an impression of a [[nautilus]] to the [[Royal Society]] that was more than two feet in diameter,<ref>{{Cite book |url=https://archive.org/details/forgottengeniusb0000inwo |url-access=registration |page=[https://archive.org/details/forgottengeniusb0000inwo/page/403 403] |quote=hooke nautilus. |title=The Forgotten Genius: The Biography of Robert Hooke, 1635–1703 |last=Inwood |first=Stephen |date=2005 |publisher=MacAdam/Cage Publishing |isbn=978-1-59692-115-3 |language=en}}</ref> and morphologically distinct from any known living species. [[Robert Hooke|Hooke]] theorized that this was simply because the species lived in the deep ocean and no one had discovered them yet.<ref name=":12" /> While he contended that it was possible a species could be "lost", he thought this highly unlikely.<ref name=":12" /> Similarly, in 1695, [[Sir Thomas Molyneux]] published an account of enormous antlers found in [[Ireland]] that did not belong to any extant taxa in that area.<ref name=":32" /><ref name=":22">{{cite journal |last1=Molyneux |first1=Thomas |author-link1=Sir Thomas Molyneux, 1st Baronet |title=II. A discourse concerning the large horns frequently found under ground in Ireland, concluding from them that the great American deer, call'd a moose, was formerly common in that Island: with remarks on some other things natural to that country |journal=Philosophical Transactions of the Royal Society of London |date=April 1697 |volume=19 |issue=227 |pages=489–512 |doi=10.1098/rstl.1695.0083 |bibcode=1695RSPT...19..489M |s2cid=186207711}}</ref> Molyneux reasoned that they came from the North American [[moose]] and that the animal had once been common on the [[British Isles]].<ref name=":32" /><ref name=":22" /> Rather than suggest that this indicated the possibility of species going extinct, he argued that although organisms could become locally extinct, they could never be entirely lost and would continue to exist in some unknown region of the globe.<ref name=":22" /> The antlers were later confirmed to be from the extinct [[deer]] ''[[Megaloceros]]''.<ref name=":32" /> Hooke and Molyneux's line of thinking was difficult to disprove. When parts of the world had not been thoroughly examined and charted, scientists could not rule out that animals found only in the fossil record were not simply "hiding" in unexplored regions of the Earth.<ref name="Watson2">''Ideas: A History from Fire to Freud'' ([[Peter Watson (business writer)|Peter Watson]] Weidenfeld & Nicolson {{ISBN|0-297-60726-X}}){{page needed|date=February 2022}}</ref>

[[Georges Cuvier]] is credited with establishing the modern conception of extinction in a 1796 lecture to the [[French Institute]],<ref name=":52" /><ref name=":42"/> though he would spend most of his career trying to convince the wider scientific community of his theory.<ref name=":62">{{Cite book |title=Perilous planet earth : catastrophes and catastrophism through the ages |last=Trevor |first=Palmer |date=2003 |publisher=Cambridge University Press |isbn=978-0-521-81928-2 |oclc=912273245}}{{page needed|date=February 2022}}</ref> Cuvier was a well-regarded geologist, lauded for his ability to reconstruct the anatomy of an unknown species from a few fragments of bone.<ref name=":52" /> His primary evidence for extinction came from mammoth skulls found near [[Paris]].<ref name=":52" /> Cuvier recognized them as distinct from any known living species of elephant, and argued that it was highly unlikely such an enormous animal would go undiscovered.<ref name=":52" /> In 1798, he studied a fossil from the [[Paris Basin]] that was first observed by [[Robert de Lamanon]] in 1782, first hypothesizing that it belonged to a canine but then deciding that it instead belonged to an animal that was unlike living ones. His study paved the way to his naming of the extinct mammal genus ''[[Palaeotherium]]'' in 1804 based on the skull and additional fossil material along with another extinct contemporary mammal genus ''[[Anoplotherium]]''. In both genera, he noticed that their fossils shared some similarities with other mammals like [[ruminant]]s and [[rhinoceros]]es but still had distinct differences.<ref>{{cite book |editor-last1=Chemla |editor-first1=Karine |editor-last2=Keller |editor-first2=Evelyn Fox |last=Belhoste |first=Bruno |year=2017 |title=Cultures without Culturalism: The Making of Scientific Knowledge |chapter=Chapter 10: From Quarry to Paper. Cuvier’s Three Epistemological Cultures |publisher=Duke University Press |pages=250–277}}</ref> In 1812, Cuvier, along with [[Alexandre Brongniart]] and [[Isidore Geoffroy Saint-Hilaire|Geoffroy Saint-Hilaire]], mapped the [[Stratum|strata]] of the Paris basin.<ref name=":12" /> They saw alternating saltwater and freshwater deposits, as well as patterns of the appearance and disappearance of fossils throughout the record.<ref name=":32" /><ref name=":62" /> From these patterns, Cuvier inferred historic cycles of catastrophic flooding, extinction, and repopulation of the earth with new species.<ref name=":32" /><ref name=":62" />

Cuvier's fossil evidence showed that very different life forms existed in the past than those that exist today, a fact that was accepted by most scientists.<ref name=":02" /> The primary debate focused on whether this turnover caused by extinction was gradual or abrupt in nature.<ref name=":62" /> Cuvier understood extinction to be the result of cataclysmic events that wipe out huge numbers of species, as opposed to the gradual decline of a species over time.<ref name=":8">{{Cite book |last1=M. J. S. |first1=Rudwick |title=Georges Cuvier, fossil bones, and geological catastrophes : new translations & interpretations of the primary texts |last2=Cuvier |first2=Georges |author-link2=Georges Cuvier |date=1998 |publisher=University of Chicago Press |isbn=978-0-226-73106-3 |oclc=45730036}}{{page needed|date=February 2022}}</ref> His catastrophic view of the nature of extinction garnered him many opponents in the newly emerging school of [[uniformitarianism]].<ref name=":8" />

[[Jean-Baptiste Lamarck]], a [[Gradualism|gradualist]] and colleague of Cuvier, saw the fossils of different life forms as evidence of the mutable character of species.<ref name=":62" /> While Lamarck did not deny the possibility of extinction, he believed that it was exceptional and rare and that most of the change in species over time was due to gradual change.<ref name=":62" /> Unlike Cuvier, Lamarck was skeptical that catastrophic events of a scale large enough to cause total extinction were possible. In his geological history of the earth titled Hydrogeologie, Lamarck instead argued that the surface of the earth was shaped by gradual erosion and deposition by water, and that species changed over time in response to the changing environment.<ref name=":62" /><ref>{{Cite book |title=The age of Lamarck : evolutionary theories in France, 1790–1830 |last=Corsi |first=Pietro |publisher=University of California Press |isbn=978-0-520-05830-9 |oclc=898833548 |year=1988}}{{page needed|date=February 2022}}</ref>

[[Charles Lyell]], a noted geologist and founder of [[uniformitarianism]], believed that past processes should be understood using present day processes. Like Lamarck, Lyell acknowledged that extinction could occur, noting the total extinction of the [[dodo]] and the extirpation of [[History of the horse in Britain|indigenous horses]] to the British Isles.<ref name=":12" /> He similarly argued against [[mass extinction]]s, believing that any extinction must be a gradual process.<ref name=":52"/><ref name=":42" /> Lyell also showed that Cuvier's original interpretation of the Parisian strata was incorrect. Instead of the catastrophic floods inferred by Cuvier, Lyell demonstrated that patterns of saltwater and freshwater [[Deposition (geology)|deposits]], like those seen in the Paris basin, could be formed by a slow rise and fall of [[sea level]]s.<ref name=":32" />

The concept of extinction was integral to [[Charles Darwin]]'s ''[[On the Origin of Species]]'', with less fit lineages disappearing over time. For Darwin, extinction was a constant side effect of [[Competition (biology)|competition]].<ref>{{cite magazine |title=The Lost World |url=https://www.newyorker.com/magazine/2013/12/16/the-lost-world-2 |magazine=The New Yorker |date=9 December 2013 |access-date=9 February 2022 |archive-date=3 February 2023 |archive-url=https://web.archive.org/web/20230203051615/https://www.newyorker.com/magazine/2013/12/16/the-lost-world-2 |url-status=live}}</ref> Because of the wide reach of ''On the Origin of Species'', it was widely accepted that extinction occurred gradually and evenly (a concept now referred to as [[Background extinction rate|background extinction]]).<ref name=":42" /> It was not until 1982, when [[David M. Raup|David Raup]] and [[Jack Sepkoski]] published their seminal paper on mass extinctions, that Cuvier was vindicated and catastrophic extinction was accepted as an important mechanism{{Citation needed|reason=A lot of history separates Cuvier from Raup and Sepkoski's 1982 work, including such figures as Bretz from the University of Chicago|date=February 2024}}. The current understanding of extinction is a synthesis of the cataclysmic extinction events proposed by Cuvier, and the background extinction events proposed by Lyell and Darwin.