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
Genetics and the Origin of Species series of notable books: "Systematics and the Origin of Species" (1942) by Ernst Mayr; "Tempo and Mode in Evolution" (1944) by George Gaylord Simpson; and "Variation and Evolution in Plants" (1950) by G. Ledyard Stebbins. The emerging synthesis was called the evolutionary synthesis by Julian Huxley in his book, "". In 1947, a diverse collection of biologists met at a symposium in Princeton and declared their acceptance of this synthesis. However, it was not yet complete. Developmental biologists did not accept that the theory explained their observations, and it was not until the 1970s and 1980s that molecular biology bridged