sexual selection- 6

Question 1

define intrasexual selection?

Answer 1

competition within sex for mating access

Question 2

intersexual selection?

Answer 2

selection by one sex for traits in the other

Question 3

2 fold disadvantage to sex?

Answer 3

• if asexual and sexual produce the same amount of offspring the asexual will have twice as many daughters
• asexual should replace sexual due to rapid increase

Question 4

advantages of sex?

Answer 4

• combines beneficial mutations (from 2 individuals)
• generation of novel genotypes through recombination
• faster evolution due to increased genetic variance in offspring (red queen)
• clearance of deleterious mutations

Question 5

red queen hypothesis?

Answer 5

evolutionary arms race between parasite and sexually reproducing organism
-novel genotypes and quick evolution helps to evolve resistance

Question 6

evidence for red queen hyp?

Answer 6

in a study of new zealand freshwater snails in lakes with more parasites there were more males present in lakes with more parasites

Question 7

why should sex lead to sexual selection?

Answer 7

this is because of anisogamous gametes (different sizes/strategies). so different costs to each sex. leads to sexual conflict and selection

Question 8

for the organism what are the preferential strategies for M and F?

Answer 8

• males reproduction increases with the number of mates

- females increases with the best possible male to increase fitness of offspring

Question 9

example of species where sexual conflict informs differing strategies?

Answer 9

• Dunnocks and their mating systems

- main mating system is polyandry

Question 10

models to explain preferences for certain traits- direct benefit model?

Answer 10

the non limiting sex provides direct benefit to the limiting sex such as parental care, protection from predation,resources, territory

Question 11

(indirect) runaway sexual selection ‘sexy son’?

Answer 11

son has improved success because he inherited traits that made father appealing to the mother
-this is an arbitrary mechanism

Question 12

(indirect) good genes/ indicators, handicap model?

Answer 12

the trait the males possesses indicates high viability (the trait correlates with high genetic quality)

Question 13

hamilton zuk hypothesis?

Answer 13

that sexual ornaments are indicators of parasite/ disease resistance (good genes model)

Question 14

sensory bias hypothesis?

Answer 14

this is a preexisting bias model. the preference is an artefact of how they are wired.
-feed on red berries- mate choice red

Question 15

types on intrasexual selection?

Answer 15

• precopulatory- fighting, singing

- post copulatory- spermicides