If switched to snails large jaws will be seen again. E. Chance and non-random events both occur in natural selection. A. Random events 1. Each step in natural selection works by an improvement on a previous trait. IF all of these are true, the trait will respond to natural selection.
Natural selection favors the large, strong and aggressive over the small weak and timid.
Traits that benefit survival of the species will evolve by NS even if they reduce individual survival and reproduction. The reverse is correct. Traits that benefit individual survival and reproduction will evolve by NS even if detrimental to species survival. Animals compete so only the strongest will survive in order to assure health of the species. NO Animals compete when successful competitors have increased survival and reproduction not for the good of the species.