Here is how Darwin himself: Darwin 1964 [1859], p. 61.

by the term of Natural Selection: A highly accessible description of natural selection can be found in Mayr 2001. A textbook on selection is Bell 2008. Endler 1986 presents much of the evidence for natural selection.

Wallace wrote to Darwin: Marchant 1916, p. 171.

philosophical radicals such as the political economist Thomas Malthus: Malthus argued in his An Essay on the Principle of Population (published in 1798) that humans produce too many offspring and that, consequently, if unchecked, famine and “premature death must in some shape or other visit the human race.” Malthus’s ideas influenced not just Darwin and Wallace but also economic and political philosophy.

Darwin himself wrote to the geologist: The geologist Frederick Wolaston Hutton (1836–1905) reviewed The Origin for the Geologist.