Behavior Chapter 39

Behavior is what an animal does and how it does it Behavior is influenced by innate (present at birth) and learned factors. Behavioral ecology emphasizes evolutionary hypotheses. Optimal behavior = A behavior that maximizes individual fitness. Optimal behavior is a valid concept if behavior is genetically influenced and subject to natural selection.

A behavior has both an ultimate and a proximate cause Ultimate causation = The evolutionary reason for the existence of a behavior. Proximate causation = The immediate cause and/or mechanism underlying a behavior.

Fixed-action pattern = A highly stereotyped, innate, behavior. Innate behaviors Fixed-action pattern = A highly stereotyped, innate, behavior. Sign stimulus = An external sensory stimulus which triggers a fixed-action pattern.

Learning is modification of behavior While European ethologists were discovering innate behaviors in nature, American psychologists were finding learning abilities in lab animals. Nature versus nurture = The debate over whether instinct or learning is of primary importance in animal behavior. Modern biologists feel that behavior is a result of genetic and environmental factors.

Changing behavior Habituation = Learning to ignore irrelevant stimuli or stimuli that do not provide proper feedback. Imprinting is a form of learning closely associated with innate behavior. (Konrad Lorenz) Imprinting stimulus = An object in the environment to which the response is directed. Critical period = A limited time during which imprinting can occur.

Conditioning Classical conditioning = A process in which an animal learns to respond to an external stimulus which does not normally elicit that response. Operant conditioning = A process where an animal learns to associate one of its behaviors with a reward or punishment and then tends to repeat or avoid that behavior.

Animals repeat behaviors at regular intervals (daily, seasonally). Rhythmic behaviors Animals repeat behaviors at regular intervals (daily, seasonally). Circadian (daily) rhythms are regulated by environmental cues. Light is the most common external cue (nocturnal/diurnal). Breeding and hibernation are partially based on physiological and hormonal changes linked to external factors such as day length.

Environmental cues guide animal movement Animals use a variety of cues to guide them in their movements. Kinesis = A randomly directed change in activity rate in response to an environmental stimulus. Taxis = An oriented movement toward or away from a stimulus. (chemotaxis, phototaxis, geotaxis)

Social behavior Social behavior = Interaction between two or more animals. (Signals include physical movement and chemicals.) Agonistic behavior = A contest of threat displays which continues until a participant submits and yields access to a resource (e.g. mate, food, territory). Ritual = Symbolic behavior that minimizes the possibility of serious injury to the antagonists. Territoriality = defense of areas typically used for feeding, mating, rearing young etc.

Mating Systems Promiscuous = A mating system with no strong pair-bonds or lasting relationships. Monogamous = A mating system where one male mates with one female. Polygamous = A mating system where an individual of one sex mates with several of the other. • Polygyny is a mating sub-system where one male mates with multiple females. • Polyandry is a mating sub-system where one female mates with multiple males.

Mating Systems (cont) Certainty of paternity is relatively low in species with internal fertilization because mating and birth (or egg laying) are separated over time. Exclusive male parental care is rare in birds or mammals. Certainty of paternity is higher when egg laying and mating occur together, as in external fertilization. Parental care, when present, in fishes and amphibians is as likely to be by males as by females.

Fitness and altruistic behavior Altruistic behavior = A behavior that reduces an individual's personal welfare but benefits others. Inclusive fitness = The reproductive fitness of an individual as measured by its offspring and assistance to the reproductive efforts of close relatives. Kin selection = The mechanism of increasing inclusive fitness.