Joel A. C. Baum and Jitendra, V. Singh, Organization-Environment Coevolution, pp. 379-402 in Joel Baum and Jintendr Sing, eds. The Evolutionary Dynamics of Organzations, New York, NY, Oxford University Press, 1994.

Organizations influence their environments, and vice versa. The authors study the simultaneous evolution, or co-evolution of organizations and their environments. This approach assumes that changes may occur in all interacting populations or organizations, permitting change to be driven by both direct interactions and feedback from the rest of the system.

What is Organization-Environment Coevolution?

It requires that all changes in all interacting organizations result from direct and indirect feedback. An organization that stimulates the evolution of another organization is, in turn, itself responsive to that evolution, and the response is predictable.

In direct coevolution, two populations evolve in response to each other. In diffuse coevolution, one or more populations evolve in response to several other organizations in a community. In some situations there may be standard evolution as well. Coevolution implies nonlinear feedback among interacting populations.

Why Study Coevolution?

It is potentially more applicable in complex situations.

An Application to Coevolution in Ecological Communities

Community level interactions moderate population dynamics by altering selection pressures.

Coevolution in Ecological Communities

The instantaneous rate of population change dN/Dt = rN(1-N/K) where r is growth rate, N is population size, and K is carrying capacity. Over time the population size is self correcting, defined as loop dominance.

But populations also affect other populations. The size of one population can affect the rate of another population through competition. These are negative feedback loops. There can be competition and self-effect loops (either positive or negative). Self-effects are used to model the self-dampening effects of variables on their own growth.

Unlike the single system, the competitive system is potentially unstable. It could cause an increase in A to lower A, leading to a decrease B which decreases A and so on, creating a vicious downward cycle. In general the coexistence of competitors requires that the effects of competition within population must be stronger than the competitive effects between populations. If they are highly competitive any disturbance can knock them permanently off equilibrium.

Another interaction is predator-prey. Without predators the prey have a normal growth behavior, without prey the predators die out. Since the prey have a positive effect on the predators (rather than both mutually negative) the system is stable. Thus the growth rate of one organization is affected by another organization.

Qualitative Modeling of Coevolutionary Systems

This approach permits the inclusion of variables which are difficult to measure, as long as the direction of effect is known. It emcompasses paths between variables, loops and loop lengths. Conjunct loops have a common variable, disjunct loops do not. Feedback can be positive or negative. Feedback level is the number of variables in the feedback loop.

System Stability

For stability, feedback at all levels greater than 0 must be negative. Negative feedback in high level loops cannot be too strong relative to lower level loops.

Predicting Change

You can use differential equations to predict the change of one variable with the change in another. The equations show that sometimes the result of a change is not intuitive.

Coevolution in a Child Care System

The authors treat day care centers and nursery schools as distinct populations.

Models of the Child Care System

This model shows that:

* the impact of a change to the structure of the system can be felt at places removed from the change

* the patterns of correlations among variables depend not only on the relations of these variables themselves, but also on interactions in the rest of the system.

Implications

With the coevolutionary approach one can begin to understand the relationships between a set of organizations as a system. Due to feedback mechanisms changes in one area can produce non-intuitive changes to other areas. In complex systems of relationships, dependent-independent variable distinctions become less meaningful since changes in any one variable are caused endogenously by changes in others.

It's also important when the environment changes in response to the community system as well. Public policy is one applicable area. This shows how a well-intentioned policy can sometimes have surprising consequences when feedback relationships exist.

Sometimes it shows that it is in the best interest to promote the welfare of other systems to help your own.

Also in arms races or technological innovation mutual competition can be co-evolutionary, when competitors respond to and influence the actions of others. Or sometimes the environment of an organization continues to deteriorate because other species continue to evolve. Each speciies has to evolve faster just to hold its own against others.

In technology, this effect requires that continuous improvement be sustainable. It also means that in some situations it is advantageous to develop competitors, especially when legitimacy is being estabilished.