Editing On the Origin of Species (section)

===Events leading to publication: "big book" manuscript===
[[File:Alfred Russel Wallace 1862 - Project Gutenberg eText 15997.png|thumb|upright|A photograph of [[Alfred Russel Wallace]] (1823–1913) taken in [[Singapore]] in 1862]]
An 1855 paper on the "introduction" of species, written by [[Alfred Russel Wallace]], claimed that patterns in the geographical distribution of living and fossil species could be explained if every new species always came into existence near an already existing, closely related species.<ref>{{citation | last=Wallace | first=Alfred R. | title=On the law which has regulated the introduction of new species |journal=Annals and Magazine of Natural History | year=1855 | volume=16 | issue=93 | pages=184–196 | url= http://darwin-online.org.uk/content/frameset?viewtype=text&itemID=A11&pageseq=1 | doi=10.1080/037454809495509}}</ref> [[Charles Lyell]] recognised the implications of Wallace's paper and its possible connection to Darwin's work, although Darwin did not, and in a letter written on 1–2 May 1856 Lyell urged Darwin to publish his theory to establish priority. Darwin was torn between the desire to set out a full and convincing account and the pressure to quickly produce a short paper. He met Lyell, and in correspondence with [[Joseph Dalton Hooker]] affirmed that he did not want to expose his ideas to review by an editor as would have been required to publish in an academic journal. He began a "sketch" account on 14 May 1856, and by July had decided to produce a full technical treatise on species as his "big book" on ''[[Natural Selection (manuscript)|Natural Selection]]''. His theory including the principle of [[Genetic divergence|divergence]] was complete by 5 September 1857 when he sent [[Asa Gray]] a brief but detailed abstract of his ideas.<ref name=Quammen135-158>{{Harvnb|Quammen|2006|pp=135–158}}</ref><ref name="letters: Big Book">{{cite web | title=Darwin in letters, 1856–1857: the 'Big Book' | website=Darwin Correspondence Project | date=12 June 2015 | url=https://www.darwinproject.ac.uk/letters/darwins-life-letters/darwin-letters-1856-1857-big-book | access-date=21 March 2016}}<br/>{{cite web |url= http://www.darwinproject.ac.uk/DCP-LETT-1870 |title= Letter 1870 – Darwin, C. R., to Hooker, J.D., 9 May (1856) |publisher=Darwin Correspondence Project | access-date=21 March 2016 }}</ref>