Ecological Theory

The sociological versions of ecological theory connect social entities with their environments. While most modern applications of ecological theory have been studies of populations of business firms, there is a recent trend toward applications in sociology more broadly conceived. The two fundamental processes in ecological theory are adaptation and selection. Adaptation is the process by which a social entity changes in order to survive optimally within a given environment. Selection is the process through which entities that are less fit (i.e., less adapted to a set of environmental conditions) survive at lower rates than entities that are more fit, and therefore become less prevalent in the population.

At the population level, adaptation and selection are logically related. Adaptation at one level is typically created by selection at the next lower level of analysis. For example, when an organization adapts to its environment by seizing strategic possibilities and implementing a change in its goals, products, or members, its behaviors or members are being selected by environmental conditions. The lower level (behavioral or constituent) is being selected, producing adaptation in the form of changes at the organizational level. Conversely, organizations that do not adapt to the environmental conditions will survive at lower rates, producing a shift in the population distribution of organizations.

As a dynamic theory of social process, ecological theory is an explanation of the evolution of social forms. The theory argues that social forms (often organizations or associations, but see the concluding section of this essay) change over time as they compete for resources in an environment. The competition among entities that drives modern theories within this school of thought is ecological competition as opposed to economic competition. That is, ecological competition does not require a conscious orientation toward the competition, or even an awareness of it. All that is required is a population of social entities that use the same resource dimension, where there is some limit on the availability of that resource and there is some inertia in the ability of entities to shift from one resource or place to another. Formally, two populations of social entities compete if growth in one of them decreases the rate of growth in the other one.

The concept of niche summarizes the fact that social entities have a location within an often multidimensional resource environment. Ecological competition occurs among all entities that use the same resources (occupy the same niche). The fundamental niche is the hypothetical location in the multidimensional resource space that a population would occupy if it had no competitors. When observed, however, populations are constrained by competition with other entities that use parts of the same niche. Their observed location is the realized niche.