Social change, in sociology, the alteration of mechanisms within the social structure, characterized by changes in cultural symbols, rules of behavior, social organizations, or value systems.
Throughout the historical development of their discipline, sociologists have borrowed models of social change from other academic fields. In the late 19th century, when evolution became the predominant model for understanding biological change, ideas of social change took on an evolutionary cast, and, though other models have refined modern notions of social change, evolution persists as an underlying principle.
Other sociological models created analogies between social change and the West’s technological progress. In the mid-20th century, anthropologists borrowed from the linguistic theory of structuralism to elaborate an approach to social change called structural functionalism. This theory postulated the existence of certain basic institutions (including kinship relations and division of labor) that determine social behavior. Because of their interrelated nature, a change in one institution will affect other institutions.
Social change can evolve from a number of different sources, including contact with other societies (diffusion), changes in the ecosystem (which can cause the loss of natural resources or widespread disease), technological change (epitomized by the Industrial Revolution, which created a new social group, the urban proletariat), and population growth and other demographic variables. Social change is also spurred by ideological, economic, and political movements. (https://www.britannica.com/topic/social-change)
Sociology Through Heidi's Eyes 