Experimental Approaches to the Study of Evolution

Abstract

Abstract The study of evolution, a historical phenomenon, can be frustrating; historical subjects are seldom amenable to experimentation, and inferences about them depend on arguments of plausibility and likelihood. Further, evolutionary change is usually slow relative to the rate at which human patience is exhausted, so the phenomena under scrutiny take a long time to unfold before they become recognizable history. Nonetheless, the power of the experimental method can be used to study, in real time, some of what has unfolded and why. Our goal in this chapter is to focus on such experimental approaches; we argue that these methods, when combined with historical or comparative approaches, allow direct tests of certain kinds of hypotheses about evolution. Specifically, we examine how experimental approaches can be used to test hypotheses about the action of selection in natural populations. First, we distinguish a variety of comparative and historical methods, discuss how experimental approaches ought to dovetail with those methods, and illustrate our points with a specific example. We then place these experimental approaches in a larger context and categorize the variety of expeimental approaches by their goals and methods. These experiments and methods are designed to measure the extent of genetic variation for the traits under scrutiny and to elucidate the action of natural selection. For clarity, we focus on the action of selection on morphological, physiological, or life history traits.