Natural selection is a process that causes heritable traits that are helpful for survival and reproduction to become more common, and harmful traits to become rarer. This occurs because organisms with advantageous traits pass on more copies of these traits to the next generation.Over many generations, adaptations occur through a combination of successive, small, random changes in traits, and natural selection of those variants best-suited for their environment.In contrast, genetic drift produces random changes in the frequency of traits in a population. Genetic drift arises from the element of chance involved in which individuals survive and reproduce.In biology, evolution is the change in the inherited traits of a population from generation to generation. These traits are the expression of genes that are copied and passed on to offspring during reproduction.
