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Study Guide Lectures 17-23

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University of Toronto St. George
Ingrid L.Stefanovic

Lecture 17: Different mating system : Monogamy J sexes pair for breeding season for life J very rare J one to one J seahorses, sexual selection low J male and females have similar morphology Polygyny J males mate multiple in a breeding season J elephant seals J low parental investment J females are limiting resources J males mates multiple to maximize the fitness Polyandry J females mate multiple in a breeding season J pipefish J male limit resource J females mate multiple to max the fitness Intersex conflicts J female resist mating while male tend to overcome and mate Claspers J used to hang on females Sex role reversal J female-female competition and male choice Eg. Giant water bugs, pipefish (male has brood pouch, male reproductive success depends on the size of the pouch), katydids (flexible sex roles in Katydids J low food level, female mate more than males, males become choosy when food level is low J hard for them to produce sperms. High food level J male mate more J less chosier), spotted sand piper, plover Rock-paper-scissors game in nature: Side-blotched lizards J yellow, blue and orange If blue is high, orange will increase If yellow is high, blue will increase If orange is high, yellow will increase Little is static in mating system!!! Lecture 18: Non-selfish behaviours J altruism and cooperation Hypo to explain coorperative behaviour: reciprocity altruism J the cost will be repaid in the future kin selecion J help other closely related ones J the donor of a cooperative behaviour increase hisher inclusive fitness by helping a relative to reproduce and leave more offspring. Coorperative behaviours can evolve when: rb-c is greater than 0 B=benefit c=cost r=coefficient of relatedness Group selecion J the cost of a individual is offset compare the benefit to the whole group Kin selection model showed a perfect relationship between the degree of relatedness and 2} }}]72}Zo ]}L]ZZ}}7oZ][s contradict the theory of natural selection which states that fitness differ among individuals Eusociality J individuals in this species forego production all together Social behaviours refers to the interaction with and responses to other individuals of the same species Altruistic J Z]}]L Z}Z[Z} ]Z ZZZ]o Z][Z}L} ] success Cooperative J behaviour that if adopted by two or more individuals benefit all J }ZL[ necessary costly for individuals who participate. Game theory Jdeveloped in Cold War J some number of players J set of possible strategies J some pay- off schedule for playing A against B for all A and B J eg. Card games, chess Hawk-Dove game Contest between two individuals over obtaining a resource (food) Two strategies J hawk (fight affressively) or dove (resolve contest peacefully) R=REWARD C=COST Suppose R >2C, always good to be a hawk J independent of the number of the hawk Suppose R<2C, if hawk is common, good to be a dove, if dove is common, good to be hawk,
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