Lecture 19: Conflict and cooperation in human reproduction

Question 1

evolutionary psychology =

Answer 1

sociobiology

Question 2

human limitations:

Answer 2

• restrictions on going out and testing

- unethical

Question 3

menopause: life history theory

Answer 3

NS should synchronise senescence lifespan and reproductive functions

Question 4

menopause:

Answer 4

loss of reproductive potential and long post-reproductive life

• median age of last birth c.38
• menopause c.50
• post reproductive life = 20+ years
• -not consequence of modern medicine

Question 5

other organisms that experience menopause

Answer 5

• pilot whale

- killer whales

Question 6

hypothesis for menopause:

Answer 6

1) mother hypothesis
- – avoid risky reproduction & mortality in later life & ensure survival of existing offspring

2) grandmother hypothesis
- – gain inclusive fitness by helping existing offspring to reproduce

Question 7

mother hypothesis experiment:

Answer 7

• life history data on pre-modern Finns & Canadians
• beyond weaning, offspring fitness was not affected by maternal death?
• compensated by other family members?
• LITTLE EVIDENCE FOR MOTHER HYPOTHESIS

Question 8

grandmother hypothesis experiment:

Answer 8

• life history data on pre-modern Finns & Canadians
• number of grandchildren is correlated with post-reproductive lifespans
• • longer post-life, more grandchildren
• 2 extra g-children for every 10 years post-menopause

EVIDENCE FOR GRANDMOTHER HYPOTHESIS
- KIN selection, gain inclusive fitness

Question 9

menopause: Did grandmother hypothesis answer y menopause occurs

Answer 9

calculations show, kin selected benefits of helping don’t outweigh benefits of continued reproduction

• • also driven by reproductive competition between mother and daughters (in laws)
• -overlap between mother and child in law, reduced survival

Question 10

cooperative breeding in humans:

Answer 10

• are siblings helpers?
• – positive effect of elder sibling on survival
• – negative effect of same sex siblings on reproduction
• – overall, fitness increased by older opposite sex, red by older same sex
• – not rlly gd strong evidence for sibling as helper

are aunts and uncles helpers? NO
siblings? NO
NITSCH ET AL 2014

– cobreeding wives? no

Question 11

human mating systems:

Answer 11

• M > F rp
• 0.5% polyandrous
• 16% monogamous
• 84% polygynous

Question 12

humans polyandry

Answer 12

• Tibet & Kashmir
• usually 2-3 co-husbands
• 33% males were in polyandrous marriages
• nearly 1/3 reproductive age women not married
• MARRY BROTHERS
• • environment and culture dictate mating systems
• • conflict reduced by conflict and age hierarchy

Question 13

humans monogamy

Answer 13

• common in hunter gatherers & many other societies
• EPP an issue tho (thought to be low tho)
• serial monogamy = more partners more kids FOR MEN

Question 14

human polygyny

Answer 14

• practised widely
• resource defence polygyny: number of women married to man is linked to his landownership
• bridewealth / dowry payments
• conflict between females occurs

Question 15

human societies complexity:

Answer 15

• human societies are more complex and operate at a much larger scale than those of any other organism
• CURRIE ET AL 2010

Question 16

menopause is unusual feature likely to have resulted from

Answer 16

kin selection