On the Origin of Species for Existence" Darwin includes "slow-breeding man" among other examples of Malthusian population growth. In his discussions on morphology, Darwin compares and comments on bone structures that are homologous between humans and other mammals. Darwin's early notebooks discussed how non-adaptive characteristics could be selected when animals or humans chose mates, with races of humans differing over ideas of beauty. In his 1856 notes responding to Robert Knox's "The Races of Man: A Fragment", he called this effect sexual selection. He added notes on sexual selection to his "big book on species", and in mid-1857 he added a section heading; "Theory applied
On the Origin of Species its audience. From his early transmutation notebooks in the late 1830s onwards, Darwin considered human evolution as part of the natural processes he was investigating, and rejected divine intervention. In 1856, his "big book on species" titled "Natural Selection" was to include a "note on Man", but when Wallace enquired in December 1857, Darwin replied; "You ask whether I shall discuss 'man';—I think I shall avoid whole subject, as so surrounded with prejudices, though I fully admit that it is the highest & most interesting problem for the naturalist." On 28 March 1859, with his manuscript for the book well