A complex adaptive system is a system in which a perfect understanding of the individual parts does not automatically convey a perfect understanding of the whole system’s behavior. The study of complex adaptive systems, a subset of nonlinear dynamical systems,is highly interdisciplinary and blends insights from the natural and social sciences to develop system-level models and insights that allow for heterogeneous agents, phase transition, and emergent behavior.
They are complex in that they are dynamic networks of interactions, and their relationships are not aggregations of the individual static entities, i.e., the behavior of the ensemble is not predicted by the behavior of the components. They are adaptive in that the individual and collective behavior mutate and self-organize corresponding to the change-initiating micro-event or collection of events. They are a “complex macroscopic collection” of relatively “similar and partially connected micro-structures” formed in order to adapt to the changing environment and increase their survivability as a macro-structure.