A researcher is examining a population of butterflies in which there are two color types. One type of butterfly in this species has dark-colored wings, a second type has light-colored wings which are mostly white with gray stripes. The two types are determined by two alleles at a single gene. Based on his first survey of the population, the dark wing allele (60%) is more common than the striped wing allele (40%). After several years of research, he has found that the frequency of the striped wing allele increased to 70% while the dark wing allele has dropped to 30%. List and explain ALL THE POSSIBLE FORCES OF EVOLUTION that could be acting on the butterfly population causing this evolution to occur and describe how each of them could result in the change the researcher is seeing.