" Within Darwin’s argument for mate choice in Descent was another revolutionary idea: that animals are not merely subject to the extrinsic forces of ecological competition, predation, climate, geography, and so on that create natural selection. Rather, animals can play a distinct and vital role in their own evolution through their sexual and social choices. Whenever the opportunity evolves to enact sexual preferences through mate choice, a new and distinctively aesthetic evolutionary phenomenon occurs. "

― Richard O. Prum , The Evolution of Beauty: How Darwin's Forgotten Theory of Mate Choice Shapes the Animal World—And Us