BIOB51H3 Chapter Notes - Chapter 11: Amazon Rainforest, Mate Choice, Cucumber Beetle

What sexual selection is; the two general strategies that living things might use to achieve reproductive success. How the relative numbers of male and female individuals affect the reproductive strategy of each sex, and the characteristics of the two different strategies. Where and how sexual selection might occur in different kinds of organisms.

Demonstrating sexual selection. Two things that need to be done experimentally to show that sexual selection is occurring, and how they are done.

1.Why would you predict that females in species with internal fertilization and long periods of gestation would be choosier in selecting their mates than females in other species that lack these traits?

2.As we talked about in elephant seals, in many species, there is much greater variance in male reproductive success than in female reproductive success. This could result from a few dominant males controlling the access to the breeding grounds the females need to give birth. There are other ways, however, to get the same pattern of variance in male reproductive success WITHOUT males controlling access to a resource or to females. How might you get the same variance in male reproductive success via intersexual selection?

Suppose you were studying several species of monkeys. In one, males never helped females raise offspring. In another, males provided just as much parental care as females except for actually carrying the fetus during pregnancy. How does the fundamental asymmetry of sex compare in the two species? How would you expect sexual dimorphism to compare between the two species?