L14 - Sex Roles

Question 1

Darwin’s thoughts on sex

Answer 1

• thought males had “stronger passions” than females

- males compete for females and display their charms

Question 2

Intrasexual competition

Answer 2

intimidating, deterring, or defeating rivals to secure mates

Question 3

Intersexual competition

Answer 3

effort invested in traits to improve attractiveness to opposite sex

Question 4

Bateman’s Principles

Answer 4

• study of fruit flies provided explanation for Darwin’s observations about sex differences in mating strategies
• states that male RS more variable than female RS
• male RS increases with mating success (# of partners) while female RS peaks after a single mating

Question 5

Explanation behind Bateman’s Principle

Answer 5

• females make bigger minimum contribution to reproduction
• eggs much larger than sperm
• females limited by egg production, males limited by # of females

Question 6

‘Traditional’ Sex Roles Theory

Answer 6

-Trivers emphasized that females are limited resource for males

• natural selection leads to sex differences in mating strategy:
• males aim for intersexual selection while females aim for intersexual selection

-ideas seemed to fit prevailing gender stereotypes at the time

Question 7

Evolutionary psychology concerning female choosiness

Answer 7

• women desire less sexual partners than men
• also prefer longer period of courtship prior to sex
• less interest in short term sexual partners than men

Question 8

Sarah Hrdy’s research on langurs

Answer 8

• langurs are socially polygynous with high rates of infanticide from male group take overs
• observed females actively seek out matings with males from outside the group
• additional matings gave females infanticide protection and assuring successful reproduction

Question 9

Woman that Never

Evolved

Answer 9

• book by Sarah Hrdy
• argues that early models massively downplayed female agency in their own production
• combination of feminist critique and evolutionary biological science
• female strategies may go undetected because they are relatively deceptive or cryptic to males

Question 10

Hanna Kokko

Answer 10

-recognized that competition and choosiness can result from range of factors beyond Bateman and Trivers’ ideas about female contribution to parental investment

Question 11

Brown et. al research

Answer 11

• compiled demographic data from range of populations
• found that variance in male RS not always bigger than female RS
• in monogamous populations, there is no difference in variance in male/female RS
• males do not always benefit from more partners
• but data on # of partners rarely collected/poor quality

Question 12

Multiple Matings in Human Females

Answer 12

• Himba of Namiba: 17% of births due to EPCs, over 30% of women had extra-pair birth
• women have strong kin ties, making men less essential for reproduction
• men frequently absent bc of labor demands, makes mate guarding difficult
• women with extra-pair births had highest RS
• EPB most common in arranged marriages

Question 13

Concealed ovulation

Answer 13

-Hrdy argues that combined continuous sexual receptivity, confuses paternity and makes it difficult for males to mate guard

Question 14

several ideas as to why females maintain breast tissue while not breastfeeding

Answer 14

• conceal sexual receptively?
• promotes bonding - mimics breastfeeding mother?
• “front-bottom hypothesis”?