Sexual Selection

Sexual selection is a mechanism of evolution in which members of one sex choose mates from the other sex and compete with others of their own sex for access to mates, operating through reproductive success rather than through the survival advantage that drives natural selection; Darwin described it as a second evolutionary agency working alongside natural selection. It works through two main mechanisms: intersexual selection, in which one sex chooses mates based on attractive traits, and intrasexual competition, in which members of the same sex compete directly with each other for access to mates. These mechanisms can produce dramatic differences between the sexes, such as a peacock's plumage or a deer's antlers, traits that may even reduce an individual's chances of survival while still increasing its chances of mating.