W. G. Astley, "The two ecologies: population and community perspectives on organizational evolution", Administrative Science Quarterly, 30 (1985), 224-41.

In this paper Astley contends that while both community ecology and population ecology are mostly complimentary, community ecology better explains the mechanisms of birth and death of populations of organizations.

Community ecology applies the biological concepts of speciation , punctuated equilibrium, and ecological opportunity to organizational ecology. To community ecologists, change in organizational form occurs when a population of one form grows and "squeezes out" a population of another form.

Natural selection within a population serves to limit diversity. However, in situations of high uncertainty within a saturated population, new forms are spontaneously created. If there are excess resources available to nurture the new form, it reproduces and the resulting population grows. With sufficient numbers the population can succeed other populations and become the dominant form within a community of populations (beginning the evolutionary cycle again). Changes in technology are often the catalyst for population dynamics.

This paper is a contrasting of population ecology and community ecology.

Population ecology has failed to explain how organizational forms originate. It emphasizes forces that make the population more uniform than diverse (though population ecologists talk about diversity). Natural selection reduces rather than increases diversity (though weeding out of unfit forms).

Community ecology focuses on how populations of organizations interact with each other. The populationis their basic unit of analysis. It explains "organizational evolution as the joint product of forces that simultaneously produce homogeneity and stability within populations and diversity between them".

Technology is important in shaping population forms. Technology differences between populations serve to set up interdependencies between populations in the form of organizational communities. Technological innovation is a central force underlying evoluation within organizaitonal communities. This view sees populations in terms of their functional roles toward other populations.


Population Ecology

"Selective retention and createion at the organizational level creates metamorphosis at the population level" . In doing so it fails "to capture the evolutionary change associated either with the formation of entirely new populations or with the extinction of old ones". Population ecology focused on the regulation and growth of populations once they have been recognized as existing". It also doesn't account of the death of entire sets of populations.

Organizations within a population share a set of common core competencies. Worker flow between organizations serves to maintain stability in these competencies. The restricted flow of competencies across populations serves to isolate the population. The bandwagon effect is an example of competency flow within a population. The slow flow of innovations across populations is an example of the insularity.

This in-breeding of technical know-how stabilizes the population and limits change. "The gradual transformationof a population through natural selection only refines the basic organizational form established at the population's inception".

The population ecology view of environmental isopmorphism, where organizational form is optimized to the environmental conditions appears to be inadequate. The organizational form within a population doesn't appear to change much over time even when environmental conditions change.

Population ecology's "focus on selection through competition, therefore, points to factors that reduce rather than increase organizational variety and that effectivley slow down the rate of evolutanary change.:

It's emphisis is based on its analysis of stable, well-established populations.


Community Ecology

Most organizational change must occur in th eprocess through which new populations are born and old ones die". It is usually a spontaneous process, creating a stepwise change in population forms. This is known as "punctuated equilibrium". We can "treat the occurance of basic innovations as the establishmentof new lineages and the occurance of improvement innovations as phyletic evolution within lineages".

Also, "the birth of new organizational species (a random event) opens up new avenues of development in what is inherently an unpredictable pattern of evolution". This process of new speciation lies in a fortutious "set of conditions that promote the emergence of mutant forms". A combination of mutation and isolation is necessary for this promotion of new specities (quantum speciation ) to occur.

Technological innovation is the couterpart of biological mutation. For example, "the quasi-isolation of a cticial mass of personell in silocon Valley using similar "mutant" knowledge and operating in the same locale freed these firms from the constraints of their earlier industry."

Besides isolation "ecological opportunity" must be present for a new form to proliferate without too much competition. Each technological innovation opens up more "environmental space" for mutants to thrive without choking each other off". New forms lay claim to an environment just by being first, not by being a better (form). Organizations do not ...fortuitously fit into predefined sets of niche constraints, rather they opportunistically enact their own operating domains. Environments with fewer resource constraints are more tolerent of mutiple forms.

Organizational communities begin to function when they begin to exchange resources with each other than with the environment. As these interdependencies grow the community is less dependent on the environment, causing "community closure" which inhibits the emergence of new populations.

As the population increases until the available resources become scarce and the selection process weeds out the weaker firms. Once this stabilizes the populations, new interdependencies emerge between populations and new populations are added to fulfill functional roles until the community itself becomes saturated. The railroads and transportation system development in the US is an example of a community created by technology.

A saturated community is unstable and will collapse with new innovations. One researcher found that innovations seem to come in batches due to this effect, often spurred by economic hardship forcing adaption of new ideas to survive. The key to industrial growth lies in interlocking of mutually reinforcing technologies (innovation clustering), supported by open environmental space for growth.

"Selection is the regulator of evolutionary change, variation is its dynamo".