There have been many proponents of the idea that behavior plays a special role in evolution, yet there has been little agreement on the scope of this role and the mechanisms underlying it. In particular, progress in this area has been hampered by two main assumptions: (1) that behavior is more plastic than other traits and (2) that the role of behavior in evolution is limited to organisms with higher cognitive abilities. We argue that the range of plasticity of behavioral traits does not differ fundamentally from any other physiological or morphological trait and that this first assumption has persisted because evolutionary theory has focused on the static expression of traits even though, across taxa, dynamic expression is the norm. To assess the second assumption, we review behavioral mechanisms across taxa and show that, despite differences in complexity, the basic principles of how organisms respond to the environment are present in all organisms. In particular, behavioral responses that underlie processes like habitat selection and niche construction are universal and have the potential to impact evolutionary dynamics of all taxa. More complex behaviors like social behavior, learned responses, and problem-solving may influence evolutionary dynamics in different ways; however, rather than implying that behavior’s role in evolution is limited to a small subset of taxa, characterizing these differences and determining their consequences are the core problems of evolution. Most importantly, we suggest that past perspectives on the role of behavior in evolution can be reconciled through a systems approach which emphasizes feedbacks, nonlinear dynamics, and networks of interactions across scales.