Complex Systems Theory and Evolution

A “complex system” is a group or organization which is made up of many interacting parts. Archetypal complex systems include the global climate, economies, ant colonies, and immune systems. In such systems the individual parts—called “components” or “agents”— and the interactions between them often lead to large-scale behaviors which are not easily predicted from a knowledge only of the behavior of the individual agents. Such collective effects are called “emergent” behaviors. Examples of emergent behaviors include short and long-term climate changes, price fluctuations in markets, foraging and building by ants, and the ability of immune systems to distinguish “self” from “other” and to protect the former and eradicate the latter.