We are all a product of a long line of successful ancestors. Evolutionary approaches to behavior are concerned with adaptive behavior given an organism’s ecology. Behavior can evolve1 by means of natural selection provided there were: (a) past behavioral alternatives in an ancestral population; (b) the phenotypic differences were heritable. Specifically variation in the behavior or underlying cognitive mechanisms was based on genetic variation; and; (c) some of these behaviors and underlying cognitive mechanisms conferred a fitness advantage whereas others did not. In the following, I review some basic concepts from genetics for the introductory reader before presenting more recent developments in the study of genes and behavior.