41.1 Genes and Experience Shape Behavior
1. Ethology considers animal behavior. The field was founded on observational studies, but today it includes experimental approaches.
2. A fixed action pattern is an innate, stereotyped response that continues without feedback. A releaser is a stimulus that triggers an FAP, and it may be visual, auditory, chemical, or tactile. A supernormal releaser is an exaggerated releaser that is more effective than the natural stimulus in triggering the response. Reaction chains are sequences of FAPs.
3. Different types of learning overlap. In habituation, an animal ignores a highly repeated stimulus. In classical conditioning, an animal gives an old response to a new, conditioned stimulus instead of the older, unconditioned stimulus. In operant conditioning, a behavior changes in frequency because it is positively or negatively reinforced. Imprinting occurs during a critical period and doesn’t require reinforcement. Insight learning applies prior learning to new situations without trial-and-error activity. Latent learning uses past observations to perform a new activity.
41.2 Types of Behavior
4. Orientation and navigation rely on responses to environmental cues. Animals that navigate recognize landmarks, use the sun or stars as a compass, and possibly detect Earth’s magnetic field. Homing depends on a compass sense to set direction and a map sense to direct the navigator. The map sense may detect magnetic fluctuations, odors, or other cues.
5. Animals may fight members of their own species when they compete for resources. Territoriality and dominance hierarchies minimize aggression. Threats and appeasement, diversion, or displacement responses dampen combat. Overcrowding may trigger cannibalism, which improves the habitat for survivors.
6. Courtship rituals calm aggression so that physiologically ready individuals of the same species can mate. Mating systems include devoted pairs (monogamy), a male with multiple partners (polygyny), a female with several partners (polyandry), and group mating (polygynandry). Polygamy is mating involving multiple partners.
7. Parental investment is effort to ensure survival of one’s offspring and increases in proportion to how frequently a particular male mates with the mother of his offspring. Polygamous species are highly sexually dimorphic—the sexes appear different.
8. Altruism toward a relative, or kin selection, increases one’s inclusive fitness, thereby ensuring that some of an individual’s genes persist, if not the individual.
41.3 Animals Living Together
9. A eusocial group has cooperative care of young, overlapping generations, and division of labor. Insect societies have temporal castes, in which age determines role in the colony.
10. Group living provides the ability to alter the environment, defense, improved reproductive success, more effective foraging, and opportunity to learn. However, group living increases competition for resources and eases spread of infection.
11. A species’ social structure reflects environmental constraints. Many behaviors are based on communication, which may include chemical, auditory, tactile, visual or other types of stimuli.41.4 Three Animal Societies
12. Societies of snapping shrimp have one fertile female and live in sponges. Naked mole rats have large, complex subterranean societies. Honeybee colonies are highly regimented societies.