EVOLUTION, CHAOS, AND CLIMATE: WHAT IS THE DRIVING FORCE OF EVOLUTION?

Chaos theory is a popular mathematical theory dealing with nonlinear dynamical systems where slight perturbations of the initial starting values will lead to unpredictable results. Nonlinear dynamics is a form of mathematics where the solution to one set of equations becomes the variable in the next iteration of the function. This produces a feedback loop of sorts. Chaos theory has been used to try and explain heartbeat rhythms, economic trends, business patterns, and even evolutionary pathways. However, before now it has not taken the spotlight as the driving force of biological evolution. Chaos theory has six main components, which can be directly relate to biological evolutionary theory. Both theories state that the solutions to the problems: 1, cannot repeat themselves; 2, are bounded within a specific region of space; 3, are heavily dependent on initial conditions; 4, are not random; 5, are unpredictable; and 6, are based on a series of feedback loops. These attributes apply to both anatomical evolution, as reflected in the body fossil record, and behavioral evolution, as represented in the trace fossil record. One method for describing nonlinear systems involves the use of a phase map, which illustrates all possible solutions of a problem depending on the initial value. In biological evolutionary theory the phase map usually is called morphospace, which is the conceptual framework for mapping clusters of organisms based on specific attributes. Organisms have a tendency to group into clusters in accordance with the theory of convergences, where intermediaries are unstable. In a nonlinear phase map, these clusters would be concentrated around a point or area termed an ‘attractor’. The solutions to the equations settle down into an area influenced by the attractors until an external stimulus kicks them out. In evolution, this external stimulus is most likely a major change in some environmental factor, such as an abrupt shift in the climate. By using chaos theory as a template to study biological evolution, it may be possible to map out how changes in climate have shifted species within the framework of multidimensional morphospace.