TO Charles Darwin He was obsessed with the peacock's tail, since his theory of natural selection did not explain how a characteristic like that could have evolved, which, rather than an adaptive advantage, seemed like a defect that hindered the movement and behavior of the animal. But his naturalistic genius also made him see that to select successfully there must be a lot to choose from, that is, nature must have the greatest possible number of variations in the characteristics of all types of animals. A variety that was soon discovered to be provided by a complementary form of selection, intersexual, based on the partner selection mechanism that causes individuals of one sex to develop evolutionary characteristics to attract members of the opposite sex.
