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Month Day Topic Nov. 3 Behavior 6 Costs and benefits of behavior 8 Populations 10 Holiday! 13 Communities I 15 Communities II 17 Ecosystems Ecological studies of behavior focus on: How organisms make “decisions” that influence their survival and reproductive success. Outline • Important behaviors for survival and reproduction • Social acts The economics of behavior • Time and energy-limited • Organisms must balance tradeoffs among: – Energetic costs—food – Risk costs—mortality – Opportunity costs—missing out • Balance yields survival and reproduction How do organisms choose where to live? • Habitat cues • Good predictors of conditions suitable for future survival and reproduction How do organisms choose what to eat? Optimizing foraging choices... • Natural selection has molded behavior so that organisms make the “best possible choices” Optimizing foraging choices... • Natural selection has molded behavior so that organisms make the “best possible choices” • An organism may choose to optimize – Carbon gain – Nutrients or vitamins – Safety – Other things? How do organisms choose mates? How do organisms choose mates? • The right species How do organisms choose mates? • The right species • A high quality mate How do organisms choose mates? • The right species • A high quality mate • A mate with resources How do organisms choose mates? • • • • The right species A high quality mate A mate with resources The male/female thing… Mating tactics • Abundant sperm and scarce eggs make a female’s mate choice very important – Females—get the best sperm – Males—mate as many times as possible Mating tactics • Abundant sperm and scarce eggs make a female’s mate choice very important – Females—get the best sperm – Males—mate as many times as possible • Female choice can lead to sexual selection for exaggerated traits Mating tactics • Abundant sperm and scarce eggs make female mate choice very important • Female choice can lead to sexual selection for exaggerated traits • Social and genetic partners may differ Why live in groups? Benefits of social behavior • Protection • Foraging Subordinate member of a wolfpack Cooperative defensive behavior among musk oxen (Ovibos moschatus) Costs of social behavior • Disease • Interspecific competition for food and other resources Categories of social acts Why would an animal perform a behavior that inflicts a cost on its self? Altruistic Behavior • Nonbreeding helpers are found in mammals, birds, and insects • Altruists apparently sacrifice their reproductive success to help others • How are genes for altruism perpetuated? Altruism among genetically related individuals Kin selection: the benefits of increasing a relative’s reproductive success are greater than the cost of decreasing the altruist’s own reproductive success Theory of Indirect Selection • Genes associated with caring for relatives may be favored by selection • Altruists pass on genes indirectly by helping relatives who have copies of those genes to survive and reproduce Extreme altruism: Eusocial animals Naked Mole-Rats • Only mammals known to have a sterile worker caste • Single queen reproduces with one to three males • DNA evidence shows clan members are all closely related Altruism among unrelated individuals Reciprocity Considering Human Behavior • Some human behavior may be adaptive or may have been adaptive in the past • Testing hypotheses about human behavior can help us understand how they arose Redirected Behavior • Certain behaviors that are normally directed toward relatives may sometimes be directed toward nonrelatives • In this case, the redirected behavior is nonadaptive Human Adoption • Evolutionary theorists predict that people would be more likely to adopt related children than nonrelatives • Studies have shown that in traditional societies this is true • Adoption of nonrelatives may be an example of redirected behavior Moral Questions • A behavior that is adaptive may or may not be desirable or moral • Some behaviors that were adaptive in small groups, such as adoption, may no longer be adaptive in large societies • A nonadaptive behavior may be socially desirable