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 of Species" in 1859." Dobzhansky was plagued by a form of leukemia in his later years, but he remained vigorously active until the day before his death on December 18, 1975. During his lifetime he was the recipient of many honors and awards. For "Genetics and the Origin of Species" Dobzhansky was awarded the Daniel Giraud Elliot Medal from the National Academy of Sciences in 1941. Sixty years after its publication, the National Academy of Sciences commissioned a book entitled "Genetics and the Origin of Species: From Darwin to Molecular Biology 60 Years After Dobzhansky". It was also included in