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Darwin sexual selection definition


Sexual selectiontheory in postulating that the evolution of certain conspicuous physical traits—such as pronounced coloration, increased size, or striking adornments—in animals may grant the possessors of these traits greater success in obtaining mates.

Mutual attraction between the sexes is an important factor in reproduction. The males and females of many animal species are similar in size and shape except for the sexual organs and secondary sexual characteristics such as the breasts of female mammals. There are, however, species in which the sexes exhibit striking dimorphism or physical difference.

Particularly in birds and mammals, the males are often larger and stronger, more brightly Darwin sexual selection definition, or endowed with conspicuous ornamentation. These traits, however, make animals more visible to predators—the long plumage of male peacocks Pavo cristatus and birds of paradise Paradisaea and the enormous antlers of aged male deer Odocoileus are cumbersome loads in the best of cases. Darwin knew that natural selection could not be expected to favour the evolution of disadvantageous traits, and he was able to offer a solution to this problem.

The concept of sexual selection as a special form of natural selection is easily explained. Other things being equal, organisms more proficient in securing mates have higher fitness. There are two general circumstances leading to sexual selection.

Sexual selection is a mode...

One is the preference shown by one sex often the females for individuals of the other sex that exhibit certain traits. The other is increased strength usually among the males that yields greater success in securing mates.