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
Systematics and the Origin of Species Systematics and the Origin of Species Systematics and the Origin of Species from the Viewpoint of a Zoologist is a book written by zoologist and evolutionary biologist Ernst Mayr, first published in 1942 by Columbia University Press. The book became one of the canonical publications on the modern synthesis. Based on Mayr's Jesup Lectures delivered at Columbia University in 1941, the book combines concepts of zoology and genetics, and features Mayr's biological species concept. The biological species concept defines a species in terms of biological factors such as reproduction, taking into account ecology, geography, and life history; it remains an