Differentiation is a term in system theory (found in sociology.) From the viewpoint of this theory, the principal feature of modern society is the increased process of system differentiation as a way of dealing with the complexity of its environment.
This is accomplished through the creation of subsystems in an effort to copy within a system the difference between it and the environment. The differentiation process is a means of increasing the complexity of a system, since each subsystem can make different connections with other subsystems. It allows for more variation within the system in order to respond to variation in the environment.
Increased variation facilitated by differentiation not only allows for better responses to the environment, but also allows for faster evolution (or perhaps sociocultural evolution), which is defined sociologically as a process of selection from variation; the more differentiation (and thus variation) that is available, the better the selection (Ritzer 2007:95-96).
please see this amazing Art.. Seagull made up of many parts