In 1798 Malthus’ Essay on the principle of Population sowed a seed that was to germinate in Charles Darwin’s mind as the theory of natural selection, published in the Origin of Species in 1859. Malthus had noted that although a breeding pair generally produces a total of more than two offspring, many populations do not grow as fast as this would imply, if at all, Darwin was impressed by the subtlety of species’ adaptations and saw that individuals differed in the detail of their adaptation and thus their “fitness”, i.e. the perfection of adaptations to prevailing conditions. The variation between individuals arose from the mixing of genetic material involved in sexual reproduction, and from mutation, although the connection between these mechanisms and Darwin’s theory was not realized until 1900 when Mendal’s work of 1865 was rediscovered.
Since populations do not necessarily grow, many of the young born must die, and … Read More