sexual selection

Question 1

What is sexual selection?

Answer 1

Evolutionary explanation of partner preference

Behaviours that increase reproductive success are passed on

Question 2

What is anisogamy?

Answer 2

Differences between male and female gametes

Question 3

Describe male gametes

Answer 3

Small
Mobile
Created continuously
Don’t require much energy

Question 4

Describe female gametes

Answer 4

Large
Static
Produced at intervals during fertile years
Lots of energy

Question 5

How does anisogamy influence mate selection?

Answer 5

No shortage of fertile males
Fertile females are a rare resource
Gives rise to inter and intra sexual selection

Question 6

What is the preferred strategy of the female?

Answer 6

Inter sexual selection - quality over quantity

Question 7

How does inter sexual selection work?

Answer 7

Female makes greater investment
Consequences of wrong choice are greater for female - extra choosy
Select genetically fit partner who provides resources
Males compete for opportunity to mate with fertile female

Question 8

What is the runaway process in inter sexual selection?

Answer 8

Female preference for fit male determines which features are passed on
Height = attractive = increased in male population because sons are taller and daughters have preference for taller men
Sexy son hypothesis - female mates with man with desirable trait, trait inherited by son

Question 9

What is the preferred strategy of the male?

Answer 9

Intra sexual selection - quantity over quality

Question 10

How does intra sexual selection work?

Answer 10

Winner of competition reproduces and passes on characteristics
Causes dimorphism- obvious differences between males and females
Size matters as larger males have advantage
Females do not compete so size doesn’t matter

Question 11

What are the behavioural and psychological consequences of intra sexual selection?

Answer 11

For males to acquire females they may benefit from behaving aggressively
Preference for youth and fertility in women

Question 12

How does anisogamy dictate that men should mate with as many fertile females as possible?

Answer 12

Minimal energy for sperm

Lack of post coital responsibility of male

Question 13

Evaluation - research support for anisogamy preferences

Answer 13

Buss surveyed 10000 adults
Asked questions about age and other attributes
Females - greater value on resources such as ambition
Males - valued reproductive capacity such as good looks, young age
Reflect sex differences

Question 14

Evaluation - research support for inter sexual selection

Answer 14

Hatfield - students approached others on campus
‘I find you attractive, would you go to bed with me?’
No females said yes, 75% of men did
Females are choosier

Question 15

Evaluation - ignores social and cultural influences

Answer 15

Women no longer depend financially on men
Bereczkei - women’s preferences may not be resource oriented anymore
Chang - in China partner preferences have changed

Question 16

Evaluation - support from waist-hip ratio research

Answer 16

Singh - body size doesn’t matter but ratio does
Ratio is about 0.7
Honest signal that the woman is fertile

Question 17

Evaluation - support from lonely hearts research

Answer 17

Dunbar - more women than men offered physical attractiveness and youth (flirty etc)
Men offered resources (successful, mature), sought youth