Behavior that enables an organism to function effectively in its environment.

Adaptation describes the process of change in organisms or species to accommodate to a particular environment, enabling their survival. Adaptation is crucial to the process of natural selection. Ethologists, scientists who study the behavior of animals in their natural habitats from an evolutionary perspective, have documented two main types of adaptive behavior. Some behaviors, known as "closed programs," transmit from one generation to the next relatively unchanged. "Open genetic programs" involve greater degrees of environmental influence.

Adaptation occurs in individual organisms as well as in species. Sensory adaptation consists of physical changes that occur in response to the presence or cessation of stimuli. Examples include the...