Population dynamics is a classical area for mathematical modeling, with a rich history and many significant results. Model variables typically track the number of individuals of some homogeneous species (fixed characteristics) that interact via competition and/or predation. Community dynamics encompasses more varied forms of interactions among individuals or groups of individuals that share one or more - possibly mutable - characteristics, and individuals may be able to adapt or change identity groups. Community dynamics may give rise to collective behavior, such as swarming and other emergent phenomena. Communities may comprise organisms, cells within an organism (e.g., cancer) or even subcellular organelles. Interactions may be simple or may be arbitrarily complex such as human social dynamics.