LIFESCI 15 Lecture Notes - Lecture 14: External Fertilization, Mating System, Master Sergeant
Document Summary
Black widow mating male breaks off sex organ inside female so she can"t mate with anyone else, afterwards females try to eat the male for the offspring"s nourishment. Damsel fly shovel-penis: scoops out sperm of any other males that the female has mated with prior to mating. Sharks injects seawater into females reproductive tract that removes sperm of other males (may also kill female) Initial low reproductive investment and paternity uncertainty lead to male- male competition for access to females, indiscriminate male mating, mate guarding, and sperm wars. Monogamy (one female with one male): low variance in both, low number of mates. Q: sexual dimorphism is considered a very good predictor of mating systems. Why? (sexual dimorphism = males and females are physically different) Biological constraints make reproductive investment asymmetric more asymmetric the investment more radical the sexual dimorphism. Females lay eggs, gestation=sit on the egg, investment can be shared between males and females.
