15-human coop + conflict Flashcards
what is evolutionary psychology?
study of effects of genes on human behaviour
list 4 controversies with sociobioogy
- cultural influences + ethical difficulties of experiments
- simplistic arguments that are hard to test
- Eugenics
- motivation- not thinking about consequences
what is the life history theory for menopause?
NS should synchronise senescence of somatic + reproductive functions so individuals have capacity to reproduce throughout life
what is menopause?
loss of reproductive potential + long lost post reproductive life
in natural fertility human populations what is?|:
a) median age of final birth
b) menopause
c) post reproductive life
a) 38
b) 50
c) 20+ years
in pilot whales populations what is?|:
a) median age of final birth
b) post reproductive life
a) 36
b) 30
in killer whales populations what is?|:
a) median age of final birth
b) lifespan
a) 48
b) up to 90
list the 2 main hypotheses for menopause in humans
- mother hypothesis
- grandmother hypothesis
what is the mother hypothesis?
mother avoids risky reproduction + mortality in later life + ensures survival of existing offspring
explain Lahdenpera et al 2001 example for the mother hypothesis
life history data on pre-modern finns + canadians from church records
- evidence suggest that beyond weaning offspring fitness not affected by maternal death likely due to compensation from remaining family members
what is the grand mother hypothesis?
kin selection means that post reproductive F gain inclusive indirect fitness by helping existing offspring to reproduce
explain Lahdenpera et al 2004 example for the grand mother hypothesis (3) including what having a grandmother rather than the presence of a mother is associated with? (6)
- life history data on pre-modern finns + canadians
- no. grandchildren correlated with post reproductive lifespan
- allows daughter to have more frequent offspring as grandmother helps
associated with:
> higher fecundity
> higher LRS
> more kids if grandmother local (<20km) rather than dispersed
> earlier reproduction
> shorter birth intervals
> increased survival
which of the 2 hypotheses for menopause is accepted + which is rejected?
grandmother> accepted
mother> rejected
is there evidence for a grandfather hypothesis?
little/no effect
what did Cant + Johnstone 2008 find to prove why grandmother hypothesis may not provide the complete answer? (3)
- kin selected benefits of helping dont outweigh benefits of continued reproduction
- suggest menopause also driven/ consequence of reproductive competition between mother + daughters
- incentive to give up reproduction
how did Lahdenpera et al 2012 support findings that having grandmothers is beneficial to help with offspring?
- no overlap between offspring + grand offspring reproduction
- higher offspring survival if offspring from 1st gen does not overlap with those from the 2nd gen
what raised the idea that humans are coop breeders?
+ve effect of grannies on grand offspring production
- in humans are siblings helpers?
regarding a finnish population: - are aunties + uncles helpers?
- are coop breeding wives helpers?
- NO to all
what is the effect of siblings on survival to sexual maturity according to Nitsch et al 2013?
+ve effect + increase in overall fitness by opposite sex elder siblings but if same sex is -ve effect on number of offspring + decrease in overall fitness
which sex has the higher reproductive potential?
M- can father more offspring
how doe human societies vary/according to what?
depend on ecological conditions + cultural influences
in a study of 849 societes what % of people were each type of mating system?
polyandrous: 0.5%
monogamous: 16%
polygynous: 84%
explain the Kashmir + Tibet societies example for polyandry in humans (7)
- 2/3 husbands per wife
- 33% M aged 10-59 in polyandrous marriages
- 0.7 children per unmarried woman
- 3.3 children per married woman
- in buddhists: polyandry when severe constraints on agricultural land + when resources change polyandry abandoned
- environment + culture determine mating system
- Kinship in M + M age hierarchy reduce M conflict
in Kashmir + Tibet societies:
a) what happens when people move into towns
b) what happens to the 2nd son in buddhist populations
a) abandon polyandry to be monogamous
b) may be sent off to monastery to reduce conflict between brothers/co-husbands
in what societies is monogamy common in + what does social monogamy not mean?
hunter-gatherer + most western
- doesnt mean genetic monogamy
in monogamous populations what is the relationship between testes size vs body size in: chimps, gorillas, humans?
- chimps: large > promiscuous species
- gorillas: small > low EPP
- humans: low EPP rate historically
what is Jokela et al 2010 example of serial monogamy in the US?
studied mean no. kids at age 40-47 in men + women
- men have fitness increase with serial monogamy
- not as true for women perhaps as they reach menopause
what is serial monogamy?
having more than 1 wife/husband within single lifetime
for what 2 reasons is monogamy not as common as it seems?
EPP
serial monogamy
what can polygyny be equated to and where is it usually common?
resource defence polygyny
- wealthy high resource men
what is the Kipsigis society in Kenya example for polygyny? (5)
- if more land owned/resources then more wives
in 1267 societies:
- 66% have bridewealth payments
- more bridewealth in polygynous societies
- M need to have resources to pay this + gain wives
- 3% have dowry payments
- what is bridewealth payment?
- what are dowry payments?
- husbands family pays womens family
- wives pay family
what is polygyny like in Baka in Congo?
money used to buy wives
in terms of polygyny what does the predominant mating system influence?
financial transition between families at marriage as well as patterns of inheritance
what is the political complexity like in human societies?
at broader social level human societies more complex + operate at greater scale than any other organism
through Currie 2010 analysis of the rise + fall of political complexity what was used to show what and what was classified? (4)
- language phylogeny to evaluate evolution of language + transition between social states for 84 societies in SE Asia
- showed transition between social systems that are defined by political complexity follow predictable pathways with changes in complexity occuring
- classified societies into 4 social states:
> acephalous
> simple chiefdom
> complex chiefdom
> state
what is the acephalous social state?
simplest with individual families living together but without a chief
what is the simple chiefdom social state?
individual with authority over the community
what is the complex chiefdom social state?
social structure beneath the chief
what is the state social state?
complex society with civil service
in Currie 2010 analysis of the rise + fall of political complexity what tended to happen with increases or decreases in political complexity?
increases: tend to be in sequential jumps
decreases: either sequential jump or bigger drops in social state + can result in social collapse
what is menopause likely to have evolved from?
kin selection
what are variable human mating systems related to?
cultural + ecological factors
to some degree what do social transitions follow?
predictable pathways
