Bio 201 Problem Set 4 1 In seahorses males brood their young in a brood patch In this system reproductive success of males is limited to the number of young they can successfully provision in their brood pouch Reproductive success of females is limited to the number of eggs she can produce Studying a particular species of seahorse you find that males can brood 100 200 eggs in a season but that females can produce 400 600 eggs in a season a Which sex do you expect to be the choosy sex Why b What benefits might the choosy sex gain by being choosy 2 How can the asymmetry between the sexes explain why many fish begin their lives as females but change sex once they reach a certain size 3 Genetic Constraints 3a The following picture depicts genes A B C etc on a chromosome List the following gene pairs in order of LEAST likely to sort together to MOST likely to sort together through physical linkage A and L B and C E and K F and J Imagine a species of bird in which a fraction of the females prefer males with brightly colored plumage the rest mate randomly with respect to plumage color and that the preference is heritable The degree of brightness in plumage color of males is also heritable Finally the genotypes associated with female preference and male plumage coloration are in linkage disequilibrium 3b Of the four types of intersexual selection described in the textbook which are more likely to contribute to the above scenario Explain why why not for each 3c Describe an ecological scenario where this linkage disequilibrium imposes a constraint on evolution 4 Physical Constraints 4a Sexual dimorphism in body size is common in mammals Explain how this could relate to intrasexual selection 4b Why might sexual dimorphism in body size be reversed from the norm in flying mammals bats 5 Last week Cosmo magazine took a busload of male models to NC State as part of a GOTV get out the vote drive Why might this effort have been more successful at any other campus in the UNC system