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III. Sex and Selection A.Costs and Benefits (notes)

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1 III. Sex and Selection A.Costs and Benefits (notes)

2 III. Sex and Selection A.Costs and Benefits (notes) B.Sexual Selection - selective pressures may differ between the sexes, resulting in selection for different physiologies, morphologies, and behaviors. 1.Mating Systems: - should you have many mates or one mate? # mates # offspring male female NEWTS Jones (2002)

3 III. Sex and Selection A.Costs and Benefits (notes) B.Sexual Selection - selective pressures may differ between the sexes, resulting in selection for different physiologies, morphologies, and behaviors. 1.Mating Systems: - should you have many mates or one mate? # mates # offspring male female PIPEFISH Jones (2002)

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5 III. Sex and Selection A.Costs and Benefits (notes) B.Sexual Selection - selective pressures may differ between the sexes, resulting in selection for different physiologies, morphologies, and behaviors. 1.Mating Systems: 2. Intrasexual Selection – where competition within a sex occurs

6 Sexual Selection 2. INTRAsexual Competition - competition for harems, territories

7 Sexual Selection 2. INTRAsexual Competition - competition for harems, territories - sperm competition

8 Sexual Selection 2. INTRAsexual Competition - competition for harems, territories - sperm competition - infanticide

9 Sexual Selection 2. INTRAsexual Competition - competition for harems, territories - sperm competition - infanticide - female mimicry in male subadults and "stealth matings"

10 "sneaker males" FEMALE "Sneaker" male

11 Sexual Selection 3. INTERsexual Selection (Mate Preference) - A behavior or morphology that is only performed during the reproductive season, which increases risk and must then be offset by mating

12 Sexual Selection 3. INTERsexual Selection (Mate Preference) - A behavior or morphology that is only performed during the reproductive season, which increases risk and must then be offset by mating showy breeding plumage calling displays

13 3. INTERsexual Selection (Mate Preference) - WHY is it ADAPTIVE for the FEMALE to choose a given male?? 1. Direct Benefit - parental care

14 3. INTERsexual Selection (Mate Preference) - WHY is it ADAPTIVE for the FEMALE to choose a given male?? 1. Direct Benefit - nuptual gifts (energy for egg making)

15 3. INTERsexual Selection (Mate Preference) - WHY is it ADAPTIVE for the FEMALE to choose a given male?? 1. Direct Benefit 2. Indirect Benefit: Good Genes - ‘Handicap Theory’

16 3. INTERsexual Selection (Mate Preference) - WHY is it ADAPTIVE for the FEMALE to choose a given male?? 1. Direct Benefit 2. Indirect Benefit: Good Genes - ‘Parasite Load Theory’

17 Hmmm.... 3. INTERsexual Selection (Mate Preference) - WHY is it ADAPTIVE for the FEMALE to choose a given male?? 1. Direct Benefit 2. Indirect Benefit: Good Genes - ‘Symmetry Theory’

18 Hmmm.... 3. INTERsexual Selection (Mate Preference) - WHY is it ADAPTIVE for the FEMALE to choose a given male?? 1. Direct Benefit 2. Indirect Benefit: Good Genes - ‘Symmetry theory’

19 Hmmm.... Hey, It Works!! 3. INTERsexual Selection (Mate Preference) - WHY is it ADAPTIVE for the FEMALE to choose a given male?? 1. Direct Benefit 2. Indirect Benefit: Good Genes - ‘Symmetry Theory’

20 3. INTERsexual Selection (Mate Preference) - WHY is it ADAPTIVE for the FEMALE to choose a given male?? 1. Direct Benefit 2. Indirect Benefit: Good Genes 3. Runaway Selection


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