Sexual Selection pt. 2

Question 1

What are the three types of INTER-sexual selection?

Answer 1

1) direct benefits
2) good genes
3) runaway sexual selection (sexy sons)

Question 2

Direct benefits

Answer 2

females choose males based on display traits that honestly advertise (non-genetic) benefits that can directly increase the survival likelihood or reproductive success of an adult female herself and/or her offspring

(most likely choosing partners that provide the greatest direct benefit of parental care)

Question 3

What type of inter-sexual selection is this?

Female hanging flies get a good meal from the male. The larger the ‘nuptial gift’ the longer the mating. Male fly kills the insect and gives as nuptial gift.

Answer 3

Direct benefits

Question 4

Good genes

Answer 4

females choose males based on displays (complex songs or bright colors) that can only be produced by high quality or healthy males

Question 5

In the good genes model, how are beneficial alleles inherited?

Answer 5

inherited by BOTH daughters AND sons

Question 6

In the good genes, beneficial alleles increase what in the offspring?

Answer 6

Both survival likelihood and reproductive success for daughters and sons

Question 7

What type of inter-sexual selection is this an example of?

Female gray tree frogs prefer long calls, which can only be produced by large, healthy males

Answer 7

Good genes

Question 8

What is the handicap principle?

Answer 8

good genes model of sexual selection can also apply to traits that reduce survival likelihood

high-quality males can survive if they possess a costly or deleterious character

low quality males would be killed by the costly trait

Question 9

Runaway sexual selection (SEXY SONS)

Answer 9

females choose males based on arbitrary preference for a genetic trait

the male trait provides NO information on male quality/health OR any direct benefits

Question 10

Which model of sexual selection is demonstrated by the image below?

a. direct benefits
b. good genes
c. runaway sexual selection

Answer 10

b. good genes

Question 11

Sexual selection leads to sexual dimorphism. What is sexual dimorphism?

Answer 11

sexual selection on one sex can cause males and females of the same species to look quite different than the other.

ex. lions (the mane on the male not the female)
mandarin duck (male possesses bright colors while the female is dull and brown)