Module 2: may the forces be with you. In this module, we will discuss other mechanisms that cause evolution to occur: genetic drift, mutation, gene flow, and selection. We consider the methods that scientists use to reconstruct evolutionary history among living and extinct species, including what a species actually is, how they evolve, and how complex traits develop within a lineag through time. Genetic: genetic change in a biological population over time. Really a change in allele frequencies over time. Genetic implies that some characteristics are heritable (able to be passed from one generation to the next) Encoded information is dna: without he(cid:396)ita(cid:271)ilit(cid:455) of (cid:272)ha(cid:396)a(cid:272)te(cid:396)isti(cid:272)s the(cid:396)e (cid:449)ould(cid:374)(cid:859)t (cid:271)e e(cid:448)olutio(cid:374) Change implies the existence of a mechanism for modifying the encoded genetic information from generation to generation: mechanisms, mutation: introduces new variation to populations. Sexual reproduction: during meiosis, scrambles the already existing genetic variation into new combinations.