Chapter 1

An Introduction to Animal Behavior

1. Evolutionary theory provides the foundation for the study of animal behavior.

2. Charles Darwin realized that evolutionary change would occur if “natural selection” took place. This process happens when individuals differ in their ability to reproduce successfully, as a result of their inherited attributes. If natural selection has shaped animal behavior, we expect that individuals will have evolved abilities that increase their chances of passing copies of their genes on to the next generation.

3. Most behavioral biologists now take a gene’s eye view of evolution by natural selection. According to this view, adaptive evolution occurs through the differential survival of competing genes, which increases the frequency of those alleles whose phenotypic effects promote their own propagation.

4. Researchers interested in the adaptive value of behavioral traits use natural selection theory to develop particular hypotheses (tentative explanations) for how a specific behavior might enable individuals (not groups or species as a whole) to achieve higher reproductive success than individuals with alternative traits.

5. Behavioral traits have both ultimate (evolutionary) and proximate (immediate) causes that are complementary, not mutually exclusive. Questions about ultimate causes are those that focus on the possible adaptive value of a behavior as well as those that ask how an ancestral trait became modified over time, leading to a modern characteristic of interest. Questions about proximate causes can be categorized as those concerned with the genetic–developmental bases for behavior as well as those that deal with how physiological (neural and hormonal) systems provide the basis for behavior.

6. Adaptationist hypotheses can be tested in the standard manner of all scientific hypotheses by making predictions about what we must observe in nature in the outcome of an experiment or by comparatively exploring how traits evolved across a group of organisms over evolutionary time. Failure to verify these predictions constitutes grounds for rejecting the hypothesis; the discovery of evidence that supports the predictions means the hypothesis can be tentatively treated as true.

7. The beauty of science lies in the ability of scientists to use logic and evidence to evaluate the validity of competing theories and alternative hypotheses.