Mating Systems and Sexual Selection

Question 1

What are the 3 sex types?

Answer 1

Male, female, hermaphrodites

Question 2

When is it beneficial to be a hermaphrodite?

Answer 2

When it is rare to come across another member of the same species because of low density or mobility

Question 3

What is monogamy?

Answer 3

Mate with and stay with only 1 member of the opposite sex. Can be for life or can be seasonal. Both parents invest in raising the young

Question 4

What is promiscuity?

Answer 4

Member of one sex mating with more than 1 member of the opposite sex. Only 1 parent raises the offspring

Question 5

What is polygyny?

Answer 5

1 male mates with many females. Leads to competition among the males

Question 6

What is polyandry?

Answer 6

1 female mates with many males. The male raises the young, only seen in a few birds with shorter breeding seasons

Question 7

What is polygynandry?

Answer 7

2+ males with 2+ females mating within a group, common in primates. Reduces competition for mates, more investment in raising the young

Question 8

What determines which mating system is used?

Answer 8

The ability to defend resources, and the amount of parental care needed for the young to be successful

Question 9

What is sexual selection?

Answer 9

One sex determines the traits of the other by choosing a mate

Question 10

What is sexual dimorphism?

Answer 10

Physical differences between males and females

Question 11

How does sexual dimorphism arise? 3 reasons

Answer 11

1. different functions result in physical differences
2. intense competition between males for females
3. females choose the male with the best display/colours/song

Question 12

When does natural selection and sexual selection conflict?

Answer 12

Brightly coloured males attract more females, but are more likely to be eaten by predators. Trade off between survival and reproduction, strength of each kind of selection determines which one wins out