Chapter 11: Reproductive Behaviors

Question 1

Why do so many species produce offspring through sexual reproduction?

Answer 1

1. Increases variation in gene pool
2. Enables quick evolutionary adaptations
3. Corrects genetic errors and bad mutation

Question 2

“Sex”

Answer 2

-Biological differences

Question 3

Intersexes

Answer 3

-People who have anatomies between male and female

Question 4

Gender identity

Answer 4

• How we identify sexually and what we call ourselves

- Evidence suggests biological factors, especially prenatal hormones play a large role in gender identity

Question 5

Organizing effects

Answer 5

• Occur in the womb
• Determine if brain and body will develop male or female characteristics
• Sexual differentiation depends mostly on prenatal levels of testosterone
• Human sensitive period for genital formation is around 3rd or 4th month or pregnancy

Question 6

Steroid hormones

Answer 6

• Bind to receptors
• Activate proteins
• Activate genes

Question 7

Sex hormones

Answer 7

• Type of steroid released by testes, ovaries, & adrenal glands
  1. Androgens (mostly male)
  2. Estrogens (mostly female)
• Both sexes have both types but in different quantities

Question 8

Sex limited genes

Answer 8

-Those activated by androgens or estrogens

Question 9

Puberty

Answer 9

• Females: estrogens activate gene for breast growth

- Males: androgens activate gene for growing facial hair

Question 10

Activating effects

Answer 10

• Occur at any time of life and temporarily activate a particular response
• Both testosterone and estradiol can influence sexual arousal and response by triggering dopamine release
• Testosterone levels are correlated with “partner seeking” in males

Question 11

Evolutionary theory in variations in sexual behavior

Answer 11

• Men: brief sexual interactions with multiple partners to increase likelihood of genes being passed on
• Men more likely to be concerned about mate’s youth and fidelity –>limited fertility in women
• Women: concerned about mate’s earning potential and child commitment
• Women less likely to be concerned about man’s youth –>continued fertility
• No genetic evidence

Question 12

David Buss

Answer 12

-Believes that “typical” gender differences reflect past evolutionary pressures

Question 13

Sexual orientation

Answer 13

-Research has identified several predisposing factors in genetics and prenatal environment for male homosexuality
Stress during pregnancy may affect testosterone production
-Not related to adult hormone levels
-Twin studies suggests it’s influenced by genetics but no single gene
-Appears weaker for women
-Gender typed behaviors in childhood are a stronger predictor for men than women