Evolution is fraught with mislabelings and misunderstandings. The best-known phrase, "survival of the fittest," wittily catches its essence: evolution as a process of adaptation to changes in the environment. But that is only half the process. Most people understand "survival of the fittest" to refer to natural selection through competition for survival; in other words, the individuals of a species best suited to a particular environment will survive, on average, better than those less suited. But survival is not enough. To pass on genes to the next generation, an individual must not just survive but reproduce, which, as we know, is not straightforward. Darwin recognized the distinction between evolution through survival selection and evolution through reproductive selection, which he termed sexual selection. While natural selection operates on the relative fitness of individuals in their environment, sexual selection derives from the competition within a species for mates.
Geoffrey Miller, an evolutionary psychologist at the University of New Mexico, has argued that by the time Homo sapiens emerged on the planet 10,000 years ago, daily survival was no longer a significant factor in human evolution. The human population was small enough that there was little competition for natural resources, and humans had pretty much eliminated or learned to avoid the few remaining animals that could prey upon them. With the effects of natural selection slowed down, sexual selection gained the upper hand, leading to a runaway competition for access to the best mate.
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