Sexual Orientation Flashcards
What are ultimate causes of sexual orientation
- Maternal control of sex ratios
2. Evolution of non reproductive castes: present in social species
What are proximate causes of sexual orientation
- Sexual differentiation: Dimorphism
2. Sexual Dimorphism in brain and behavior
All humans were hunter gatherers up until 10,000 years ago. Women have a lot of work to do bc often they’re able to provide as much as their husbands do. Polygany means that:
Husband may have more than one wife. Males don’t reproduce. Males need to have resources and compete for it to have a wife.
If a woman gives birth to a son who can’t reproduce what happens?
Her fitness stops; she is no longer able to bring her genes to the next generation.
Ladies fitness depends on how she helps her relatives which is called ____ selection. You don’t have to reproduce to have an effect on fitness.
kin
_____ fitness is how much you contribute to the success of all your children.
Inclusive
When menopause arrives, they continue to provide resources, knowledge and help to their relatives which also refers to _____ selection
kin
What are advantages to controlling sex ratio?
- parental investment theory: investing in offspring
2. Polygynous Mating Systems: requires greater investment in males
What are mechanisms for controlling the sex of the offspring
- non primate mammals: sex selective abortion in nutria: fat females get aborted
- Non human primates: high ranking female baboons produce females in low quality sites and males in high quality sites.
- Humans:
- Abortions
- Infanticide
What is the Trivers Willard Hypothesis
If maternal condition is:
- Good: competitive offspring
- Poor: noncompetitive offspring
A female might gain a better fitness by producing a male homosexual offspring. Why?
Heterosexual offpspring have early risk of death. Homosexual offspring don’t participate in sports; alleviates aggression
What is the Rajput Case
Ex of infanticide
- Most elite clans had no daughters
- Subelites paid dowries to get their daughters into the highest caste thus impoverishing their sons
- poorest castes welcomed daughters; they could increase their fitness
Describe the Portuguese case
First borns remained near by. Later born males were sent off to war and their fitness suffered. The daughters were sent to cloisters where they became nuns.
What are predictive adaptive responses
If the mother looks at env and thinks they don’t feel good about it influences how much effort their going to put in their child.
Homosexuality may be an ____ response to environmental conditions
adaptive
Before the war, there were less homosexuals in Germany. Therefore the prevalence of environmental stressors induces _____
homosexuality
Mothers who are under severe stress bred _____
homosexual males.
T/F; The age of the mother is higher in male homosexuals compared to the age of heterosexual males.
True
Sry gene is on ____ chromosome which makes proteins called TDS. Expression of gene drives phenotype towards female or male. There are lots of chromosomal variations.
Y
An ____ male is usually short and are infertile
XX
Secondary sex characteristics are dependent on ______.
testosterone; masculinizes circuitry in hypothalamus and defeminizes in females.
If there are no receptors for testosterone that works then there is no _____
testosterone
_____ are derived from testosterone. It is produced in ovaries. Some estrogen is produced in males.
estradiol
Testosterone and ______ are very important in developing of genitalia and brain
dihydrotestosterone
In rats, estrogen is produced in ___ as well as with humans.
brain
Number of cells in region depends on number of _____
offspring
What does sexual dimorphism do?
- correlates with behavior
What is gonadal dysgenesis
Turners syndrome; you develop like a female; you don’t have any gonads. Petite individuals. Heterosexual females
what causes androgen insensitivity
XY males; gender identity is that of a female. They prefer males.. The XY male has androgen receptor on X chromosome, testosterone is coming from testes even though has female phenotype. Brain doesn’t see testosterone, so makes too much of it, testes becomes cancerous so you have to remove testes and prescribe ESTRADIOL. No menstruation . But chromosomal she is a male.
What happens in 5 alpha reductase deficiency
Converts testosterone to DHT. Need testosterone to masculine brain. need it to produce male genitalia. You get female genitalia
what is Congenital adrenal hyperplasia
when the clitoris looks like a penis. The adrenals produce testosterone which produce genitalia in women. The brain is masculinized. A large fraction of these women are lesbians
