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Chapter 51

Chapter 51. ~Animal Behavior. Behavior - what an animal does and why it does it. Ethology~ study of animal behavior Behavior results from both genes and environmental factors. Causation: •proximate~ physiological & genetic mechanisms of behavior

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Chapter 51

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  1. Chapter 51 • ~Animal Behavior

  2. Behavior-what an animal does and why it does it. • Ethology~ study of animal behavior • Behavior results from both genes and environmental factors. • Causation: • •proximate~ physiological & genetic mechanisms of behavior • •ultimate~ evolutionary significance of behavior

  3. Proximate Breeds in spring and early summer Hypothesis-effect of increased day length on photoreceptors brings on breeding. Stimulus results in neural and hormonal changes that induce this behavior. Ultimate Why did natural selection favor this behavior? Hypothesis-breeding is most productive or adaptive at this time. Food more plentiful. Observation of Magnolia Warbler

  4. Innate Behavior • Developmentally fixed • Often attributed to genetic programming without environmental influence. • Baby birds opening mouth for food • Key point-is the range of environmental differences among individuals does not appear to alter the behavior.

  5. Innate Behavior • Fixed action pattern (FAP)~sequence of acts; unchangeable; carried to completion • Sign stimulus~these patterns are triggered by an external sensory stimulus • Ex: 3-spined stickleback(Tinbergen ‘73 Nobel) • Utilizes its color vision to identify red-undersided males that try to invade its territory.

  6. Foraging • Mechanisms animals use to recognize, search for, and capture food items. • Optimal foraging theory • Feeding costs verses feeding benefits.

  7. Behavioral ecology concentrates on ultimate hypotheses • Animals utilize their genetic variation to express behaviors that optimize their fitness • Natural selection favors behaviors that enhance survival and reproductive success.

  8. Learning-experience based modification of behavior • Maturation~ behavior due to developing physiological changes. • Habituation~ loss of responsiveness to stimuli that convey no information; simple learning • Imprinting~ limited learning within a specific time period •critical period (Lorenz, ‘73 Nobel)

  9. Associative Learning • Connecting two different stimuli • Ivan Pavlov-Classical conditioning • Involves associating arbitrary stimuli with either a reward or punishment. • Skinner-Operant Conditioning-trial and error • Induced manipulation of levers by rats after awarding them with food.

  10. Associative Learning • •classical conditioning~ Pavlov’s dogs •operant conditioning (trial and error)~ “Skinner’s box”

  11. Social behavior • Sociobiology~evolutionary theory applied to social behavior (Hamilton) • Agonistic behavior~ contest behavior determining access to resources • Dominance hierarchy~linear “pecking order” • Territoriality~ an area an individual defends excluding others • Mating systems: •promiscuous~ no strong pair bonds •monogamous~ one male/one female • •polygamous~ one with many •polygyny~ one male/many females •polyandry~ one female/many males

  12. Agnostic Behavior • Competition for a resource • Sometimes simply ritual • Signifies intent but causes no harm • Causes social hierarchies to develop in some animals • Dominance hierarchy • Territoriality

  13. Mating behavior • Parental investment-time and resources required to produce an offspring. • Female usually has higher parental investment-eggs more costly to produce • Sexual selection-competition among males for the female to choice him. • Females usually care for young. Paternity not always know. Very few have only male paternal care.

  14. Altruistic behavior-reducing individual fitness to increase that of another • Inclusive fitness~ total effect an individual has on proliferating its genes by its own offspring and aid to close relatives • Coefficient of relatedness~measures inclusive fitness by proportion of genes that are identical because of common ancestors • Kin selection~ aiding related individuals altruistically can result in more identical genes • Reciprocal altruism~exchange of aid; humans?

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