Module 10 Flashcards
1
Q
Parental investment figures into all 3 life history tradeoffs
A
- Offspring quality vesus quantity
- Investment in current vs. future reproduction
- Mating effort versus parenting effort
2
Q
Parental Care in Humans
A
- Human children are expensive
~ Large body size and brain size
~ Born relatively helpless compared to apes, brain underdeveloped
3
Q
Altricial
A
- infants are helpless and immobile at birth, require long-term nourishment and other care in order to survive
4
Q
Precocial
A
- infants are mobile at birth and other senses are well-developed
5
Q
Humans are considered secondarily altricial
A
- because we are born more helpless than other primates
6
Q
Parental Care in Hunter-Gathers
A
- Babies spend the majority of time in direct physical contact with a parent
- Babies sleep with parents
- Babies breast-feed for 3-4 years
- Babies breast-feed on demand
7
Q
Bi-parental care (care by both parents)
A
- Considered a fundamantal adaptation for human reproduction
~ For reproduction to proceed successfully at its “normal” pace (one child every 3-4 years) in hunter-gatherer conditions, care from more than one parent is necessary
8
Q
Male care
A
- Care by males increases offspring survival at the cost of increased opportunities to bear offspring with new females
- Across species, males care is most often seen under 2 conditions
~ It is crucial to offspring survival
~ Paternity certainty is high
9
Q
IN humans, we can distinguish two types of care
A
- Direct care
- indirect care
10
Q
Direct care
A
- Carrying, play, babysitting, feeding. ACtivities that are done specifically for the child
11
Q
Indirect Care
A
- Providing resources. Involves activitied (hunting, wage earning) that benefit the child but do not require direct interaction
12
Q
Subsistence and Paternal CAre
A
- hunter-gatherer dads provide intense direct care to offspring, in addition to provisioning
- Once men can accumulate wealth, it becomes easier to “provide” indirectly
- This is also associated with degree of polygyny. Wealth increases ability to care for multiple families. Increases incentive for mate seeking at the cost of direct care
13
Q
How high is paternity certainty in human males
A
- In cases where a man has a reason to believe he is the father approximately 2-5% cross-culturally
- Sexual division of labor contributes to paternity uncertainty becasue couples are separated for long hours
- This is a low rate compared with other species
- Investment efforts is very high, so this small amount amtters
14
Q
Males are more likely to invest of
A
- The child is known to be theirs
- The child resembles them
- The mother is thought to be faithful
15
Q
Testosterone
A
- is key mediator of the trade off between parenting effort and mating effort in males
~ High elevated in mating efforts
~ Testosterone levels drop when they are parenting or with a partner
~ Testosterone stays lower if the man spends more time with the child
~ Testosterone stays high in men who are polygynously married = high mating effort
~ Testosterone is lower in men who provide direct care, not affected much in men who provide only indirect care
16
Q
Oxytocin
A
- mother are hormonally primed to invest in new infants
- Hormone oxytocin is released during childbirth and during breastfeeding
- Across a range of species, oxytocin is essential for bonding between mother and infant
- Released when a mother has physical contact with infant or hears her own infant’s cry
- Neurological pathways for oxytocin are influenced by early environments
- Postparum depression associated with reduced ozytocin response to offspring
- May be affected by nursing practices
17
Q
Parent-offspring conflict
A
- Mother is related to child by 50%
- Mother is related to other offspring by the same amount
- Child is related to itself by 100%
- Child wants maximum resources for itself
- Parent wants offspring to survive, but wants to balance investment
- Examples
~ Weaning conflicts - mothers usually want to wean offspring before offspring are willing
~ Placenta - the fetus produces hormones that manipulate the mother’s metabolism in its favor.Gestational diabetes and preeclampsia can result
~ Crying - Infants are selected to give cries that imply need to elicit preferential care
18
Q
When to terminate investment
A
- Offspring is likely to thrive without it
- Offspring is unlikely to survive
- Future reproductive prospects are good
19
Q
Mother Nature (A history of Mother, Infants and Natural Selection by Sarah Blaffer Hrdy) (Mother and other by Sarah Blaffer Hrdy)
A
Books that I might want to read later on in life
20
Q
Infanticide
A
- In a large number of species, infants are killed by male non-fathers or (rarely) by female non-mothers
- Humans are exceptional in that the majority of infant killing are preformed by the mother herself
- Infanticide is an extremely common, and often non-taboo, occurrence in traditional societies
- It is common for infants not to be considered human being until they have a been named (which can be 2 or more years)
21
Q
Most common reasons for infanticide
A
- Lack of paternal figure ~ Woman unmarried or divorced ~ Husband dead or at war - Inadequate resources ~ Twins ~ Economic hardship ~ Born too soon after previous child ~ Too many children - Inappropriate paternity ~ Incest ~ Adultery ~ Remarriage- infant sired by previous husband - Signs of poor infant quality ~ Deformed ~ Small ~ Ill ~ Rear appearance
22
Q
19th century Europe
A
- Maternal workload low, leads to high fecundity
- But financial resources often insufficient to care for children
- Made worse by trend of artificial milks and “wet nursing” by hired girls. Lifted the influence that lactation has on maternal fecundity
- Very successful practices for the wealthy, difficult for the poor
23
Q
Foundlings
A
-Milan
~ 343,406 children abandoned between 1659-1900
~ In 1875: 91% of illegitimate children abandoned
- Moscow
~ 1880-1889: 15,475 infants abandoned each years on average
- Florence
~ 1840s, 43% of baptized infants abandoned
24
Q
Consistently
A
- cited for the same reasons as infanticide
~ Especially, lack of a paternal figure, inadequacy of resources
25
"At risk" women are more likely to be pro-choice
- As are members of their families
- As are their political constituencies
- Irrespective of their religious affiliations
26
Sex-biased investment
- When males resources are unevenly distributed, males have high variance in reproductive success because the have secure more mates
~ Very successful men + many wives and children
~ Leves many men with zeros reproductive success
- Females have a high chance of marrying/ reproducing but little variance
- A successful son will yield many more grandchildren than a successful daughter
27
Sex Biased Investment in India
- Caste system
- Women must marry up in social class = hypergyny
- Brides must bring a dowry appropriate to social status
- Males can have multiple wives
28
China
- One-child policy promoted selective abortion and abandonment of females infants (1979-2015)
