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Take home final exam April 29 th DUE: May 5 th in my office by 1pm 1100 to 1300All classes meeting at 0800 or 0830MWF Exam format How many: MC? (50%) Short answer? (25%) Essay? (25%)
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Territory quality predicts helping behavior and sex of warbler offspring Female offspring are more likely to help parents As open territories diminish helping increases Higher quality territories can support more adults Can it be that females produce more females to exploit open territories? Females produce female offspring to provide help Is this a selfish strategy? So long as female offspring help parents are they effectively a non reproductive caste?
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Estimating the fitness benefits of altruistic behavior The fitness value of your 1 child: N = 1; r = 0.5 Direct Fitness = 1x0.5= 0.5 Direct Fitness = (N 1 x r 1 )+(N 2 x r 2 ) Indirect Fitness = (N 3 x r 3 ) Inclusive Fitness = (N 1 x r 1 )+(N 2 x r 2 )+(N 3 x r 3 ) Your traits Your parents traits that help you Helpful traits of your relatives Now think carefully about inclusive fitness and altruism: Do these concepts jive? Is saving your three cousins altruistic? How would a change in r affect the likelihood of evolving altruistic traits? The fitness value of your 3 cousins N=3; r=0.25 Indirect fitness = 3x0.25=0.75
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Altruism or selfishness: hymenoptera wasps Queens can directly control sex of offspring All females are capable of reproducing but only some do. Conditional strategies: Stay and help (primary helper) Leave, bread & help another nest (secondary helper) Leave, bread found a new nest
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Why help an unrelated queen? Two explanations: 1.To eventually take over the nest. 2.Opportunity to reproduce in an established nest Not competing with mom Using someone elses established resources Altruist or selfish?
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Eusociality Three characteristics of eusocial systems: 1.The mother, along with individuals (related or not), conduct cooperative care of young. 2.A reproductive division of labor emerges from sterile castes which often have certain morphological/behavioral enhancements for conducting specific tasks. 3.Generations are overlapped allowing older generations to help younger generations. Insects: 1.All known ant species 2.Most bees 3.Many wasps 4.Termites (diploid) 5.Aphids and thrips (relatively simple guard caste only) Crustaceans 1.Some shrimp Mammals 1.Naked mole rats
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Most eusocial species are haplodiploid Unfertilized these eggs would become males
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Haplodiploidy means sisters are most closely related What does this mean for measures of direct and indirect fitness? Would this facilitate the evolution of eusocial species?
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Who should a female worker bee help first? a)The queen b)A male offspring c)A female offspring What if your mother mated with 2 or more males not 1? In this case females average.5 relatedness Male female relatedness becomes equal Resources are more evenly distributed. If your more related to your sister than you’re your mother or brother then you’ll help your sister In haplodiploid systems there is a 3:1 relatedness ratio between females and males and resources in these systems are disproportionatly distributed by females to females
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