is at the phenotype level. It is the environment that choose animals.

Take the case of extreme beauty. It is almost impossible to have a beautiful person born from below average looking parents. It is more likely the beauty is from already good looking families. You can find examples from all the good looking actress.

This also illustrates the point that the extreme beauty results from a cumulative effect of different genes. It is almost impossible to have facial and body shape related genes mutating simultaneously.

Therefore, beauty is from evolution. It goes through step by step. Beautiful people will marry each other (assorted mating), the beauty gene mutations are preserved and sometimes they added together to create an extreme good looking offspring.

BTW, although beauty is about fashion, but because of assorted mating, fashionable beauty can be created within only a few generations.