Evolution is what you might call, traits that is inherited over generation to the next. An evolution is when there is a change within the genepool and it beneficial to survival. Take a giraffe for example. Back then, they had short necks and it had eat from plants on the ground. Though from generations later when they learnt that food grows on trees and stretched there necks to reach for, they now can eat from trees without a problem. Hope this helps you better understand what evolution is.
