There was a variety of feather color types in the peacock male population: dull to bright . The females picked more bright colored male than dull to mate with ; so eventually all males in population ( or vast majority) were bright feathered . That’s sexual selection.<


Over hundreds of thousands of years of _human_ evolution, starting with Homo habilis at the origin of language and culture at the beginning of the Stone Tool Made by Design Age through Homo Sapiens at the upper Design Tool Age BIGGER AND BIGGER BRAINS WERE SEXUALLY SELECTED FOR BECAUSE THEIR SUPERIOR COMMAND OF LANGUAGE AND CULTURE MADE THEM BETTER COURTERS , BETTER AT MATING .