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
Reactions to On the Origin of Species and "lifting an immense Bible first with both and afterwards with one hand over his head, solemnly implored the audience to believe God rather than man". As he admitted that the "Origin of Species" had given him "acutest pain" the crowd shouted him down. Hooker's "blood boiled, I felt myself a dastard; now I saw my advantage–I swore to myself I would smite that Amalekite Sam hip and thigh", (he was invited up to the platform and) "there and then I smacked him amid rounds of applause... proceeded to demonstrate... that he could never have read your book... wound up