Abstract

Adaptation is a defining characteristic of life. It occurs when a population of organisms becomes better suited to their environment. The phenomena that people find most fascinating about biological systems are, in general, the result of adaptive processes that occurred over the course of an extended period of time. Examples include the mammalian central nervous system, the flight of birds and insects, photosynthesis, and the human hand. However, despite the centrality of adaptation for biology, we have no generally agreed quantitative way describe the degree to which an organism is adapted. This is unfortunate, as it seems certain that the lack of a quantitative measure hinders our ability to understand what controls the degree of adaptedness in particular populations. Furthermore, a quantitative measure of adaptation may prove instrumental in guiding research in a variety sub-fields within evolutionary biology. This talk will propose a particular approach to quantifying adaptation. The approach will be compared to other possibilities drawn from the relevant theoretical literature. We will also explore some possible applications of the proposed approach to quantifying adaptation. These applications include the detection of “major transitions in evolution”, in which new “super-organisms” arise at “higher levels of biological organisation.”