Editing Evolution (section)

=== Darwinian revolution ===

The crucial break from the concept of constant typological classes or types in biology came with the theory of evolution through natural selection, which was formulated by [[Charles Darwin]] and [[Alfred Wallace]] in terms of variable populations. Darwin used the expression ''descent with modification'' rather than ''evolution''.<ref>{{Cite web |url=http://darwin-online.org.uk/content/search-results?pagesize=50&sort=date-ascending&pageno=0&freetext=descent+with+modification&allfields=&searchid=&name=Darwin+Charles+Robert&dateafter=&datebefore=&searchtitle=&description=&place=&publisher=&periodical= |title=Search results for "descent with modification" – The Complete Work of Charles Darwin Online |access-date=30 July 2022 |archive-date=5 June 2022 |archive-url=https://web.archive.org/web/20220605101314/http://darwin-online.org.uk/content/search-results?pagesize=50&sort=date-ascending&pageno=0&freetext=descent+with+modification&allfields=&searchid=&name=Darwin+Charles+Robert&dateafter=&datebefore=&searchtitle=&description=&place=&publisher=&periodical= |url-status=live}}</ref> Partly influenced by ''[[An Essay on the Principle of Population]]'' (1798) by [[Thomas Robert Malthus]], Darwin noted that population growth would lead to a "struggle for existence" in which favourable variations prevailed as others perished. In each generation, many offspring fail to survive to an age of reproduction because of limited resources. This could explain the diversity of plants and animals from a common ancestry through the working of natural laws in the same way for all types of organism.<ref name="Sober-2009">{{cite journal |last=Sober |first=Elliott |author-link=Elliott Sober |date=16 June 2009 |title=Did Darwin write the ''Origin'' backwards? |journal=[[PNAS]] |volume=106 |issue=Suppl. 1 |pages=10048–10055 |bibcode=2009PNAS..10610048S |doi=10.1073/pnas.0901109106 |issn=0027-8424 |pmid=19528655 |pmc=2702806 |doi-access=free}}</ref><ref>{{harvnb|Mayr|2002|p=165}}</ref><ref>{{harvnb|Bowler|2003|pp=145–146}}</ref><ref>{{cite journal |last1=Sokal |first1=Robert R. |author-link1=Robert R. Sokal |last2=Crovello |first2=Theodore J. |date=March–April 1970 |title=The Biological Species Concept: A Critical Evaluation |journal=[[The American Naturalist]] |volume=104 |issue=936 |pages=127–153 |doi=10.1086/282646 |issn=0003-0147 |jstor=2459191 |bibcode=1970ANat..104..127S |s2cid=83528114}}</ref> Darwin developed his theory of "natural selection" from 1838 onwards and was writing up his "big book" on the subject when [[Alfred Russel Wallace]] sent him a version of virtually the same theory in 1858. Their [[On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection|separate papers]] were presented together at an 1858 meeting of the [[Linnean Society of London]].<ref>{{cite journal |last1=Darwin |first1=Charles |author-link1=Charles Darwin |last2=Wallace |first2=Alfred |author-link2=Alfred Russel Wallace |date=20 August 1858 |title=On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection |url=http://darwin-online.org.uk/content/frameset?itemID=F350&viewtype=text&pageseq=1 |journal=[[Journal of the Proceedings of the Linnean Society of London. Zoology]] |volume=3 |issue=9 |pages=45–62 |doi=10.1111/j.1096-3642.1858.tb02500.x |issn=1096-3642 |access-date=13 May 2007 |url-status=live |archive-url=https://web.archive.org/web/20070714042318/http://darwin-online.org.uk/content/frameset?itemID=F350&viewtype=text&pageseq=1 |archive-date=14 July 2007 |doi-access=free}}</ref> At the end of 1859, Darwin's publication of his "abstract" as ''On the Origin of Species'' explained natural selection in detail and in a way that led to an increasingly wide acceptance of [[Darwinism|Darwin's concepts of evolution]] at the expense of [[Alternatives to evolution by natural selection|alternative theories]]. [[Thomas Henry Huxley]] applied Darwin's ideas to humans, using [[palaeontology]] and [[comparative anatomy]] to provide strong evidence that humans and [[ape]]s shared a common ancestry. Some were disturbed by this since it implied that humans did not have a special place in the [[universe]].<ref>{{cite encyclopedia |last=Desmond |first=Adrian J. |author-link=Adrian Desmond |encyclopedia=[[Encyclopædia Britannica Online]] |url=https://www.britannica.com/EBchecked/topic/277746/Thomas-Henry-Huxley |title=Thomas Henry Huxley |access-date=2 December 2014 |date=17 July 2014 |url-status=live |archive-url=https://web.archive.org/web/20150119231241/https://www.britannica.com/EBchecked/topic/277746/Thomas-Henry-Huxley |archive-date=19 January 2015}}</ref>

[[Othniel C. Marsh]], America's first palaeontologist, was the first to provide solid fossil evidence to support Darwin's theory of evolution by unearthing the ancestors of the modern horse.<ref>Plate, Robert. ''The Dinosaur Hunters: Othniel C. Marsh and Edward D. Cope,'' pp. 69, 203–205, David McKay, New York, 1964.</ref> In 1877, Marsh delivered a very influential speech before the annual meeting of the American Association for the Advancement of Science, providing a demonstrative argument for evolution. For the first time, Marsh traced the evolution of vertebrates from fish all the way through humans. Sparing no detail, he listed a wealth of fossil examples of past life forms. The significance of this speech was immediately recognised by the scientific community, and it was printed in its entirety in several scientific journals.<ref>McCarren, Mark J. ''The Scientific Contributions of Othniel Charles Marsh,'' pp. 37–39, Peabody Museum of Natural History, Yale University, New Haven, Connecticut, 1993. {{ISBN|0-912532-32-7}}</ref><ref>Plate, Robert. ''The Dinosaur Hunters: Othniel C. Marsh and Edward D. Cope,'' pp. 188–189, David McKay, New York, 1964.</ref>
[[File:Hesperornis Regalis - Project Gutenberg eText 16474.jpg|thumb|left|''Hesperornis regalis,'' a species of ancient flightless bird with teeth, as drawn by [[Othniel Charles Marsh|Othniel Marsh]], and published in his book, ''Odontornithes: A Monograph on the Extinct Toothed Birds of North America.'']]

In 1880, Marsh caught the attention of the scientific world with the publication of ''Odontornithes: a Monograph on Extinct Birds of North America,'' which included his discoveries of birds with teeth. These skeletons helped bridge the gap between dinosaurs and birds, and provided invaluable support for Darwin's theory of evolution.{{sfnp|McCarren|1993|pp=16–17}} Darwin wrote to Marsh saying, "Your work on these old birds & on the many fossil animals of N. America has afforded the best support to the theory of evolution, which has appeared within the last 20 years" (since Darwin's publication of ''Origin of Species).<ref>Plate, Robert. ''The Dinosaur Hunters: Othniel C. Marsh and Edward D. Cope,'' pp. 210–211, David McKay, New York, 1964.</ref><ref>Cianfaglione, Paul. "O.C. Marsh Odontornithes Monograph Still Relevant Today", 20 July 2016, ''Avian Musings: "going beyond the field mark."''</ref>