Reproductive behaviour Flashcards
Gender is defined by physical make-up and attraction. True or false?
False: humans born as one sex can consider themselves as the other. Humans can also be attracted to the same sex. GENDER IS FUCKING CONFUSING
Snails are hermaphrodite. How do they reproduce?
One snails pierces the other with a ‘calcified love dart’. The two then exchange sperm packets, and fertilise their own eggs with the other’s sperm.
What is the social hierarchy of clown fish.
Schools are led by a dominant female. When she the most dominant male changes sex and takes her place.
Define parthenogenesis, the method of reproduction in whiptail lizards.
Reproduction from the ovum without fertilisation. All whiptail lizards are female.
a) morphological sex b) psychological sex and c) sexual orientation are very different. Define them all.
a) Sex according to the physical attributes, i.e. male or female sex organs
b) Sexual identity, which sex a person perceives themselves to be
c) Which sex a person is attracted to
What is responsible for sexual identity and orientation?
Hormones.
What physical effects do sex hormones have?
They create sexual dimorphism, both in phenotype and behaviour.
What is he biological determination of gender in humans?
The X and Y chromosomes: XX is female and XY is male.
What is the biological determination of gender in humans?
The X and Y chromosomes: XX is female and XY is male.
What is the SRY gene?
A gene on the Y chromosome of therian mammals that encodes TDF (testes determining factor), a DNA-binding protein. It is this that causes XY to become male.
How do the testes stabilise sex determination?
They produce sex hormones that further determine the male condition. Testosterone up-regulates male-biased genes.
In the embryo, what are a) the Wolffian ducts and b) the Mullerian ducts?
a) Structures that form the male reproductive organs. They are present in both male and female embryos, yet in females they regress and in males they are stabilised by testosterone.
b) Forms the female reproductive organs
Define an androgen.
Male sex hormones.
Define an oestrogen.
Female sex hormones.
Only males have androgens and only females have oestrogens. True or false?
False: both sexes have both but each is more concentrated in one.
What is the SRY gene?
A gene on the Y chromosome of therian mammals that encodes TDF (testes determining factor), a DNA-binding protein. It is this that causes XY to become male. TDF forms the testes.
In the embryo, what are a) the Wolffian ducts and b) the Mullerian ducts?
a) Form the male reproductive organs. They are present in both male and female embryos, yet in females they regress and in males they are stabilised by testosterone.
b) Forms the female reproductive organs. They are present in both male and female embryos, yet in males they regress.
The genitalia differentiate early in development. True or false?
False: they remain undifferentiated for a while.
Sex hormones are all steroid hormones. True or false?
True.
The effects of sex hormones fall into 2 categories. What are they?
- Organisational
2. Activational
Explain what is meant by an organisational effect of sex hormones.
Control of sexual differentiation (physical)
Explain what is meant by an activational effect of sex hormones.
Control of sexual behaviour
a) define lordosis
b) what happens when male rats with their genitals removed are injected with oestrogen?
a) Arching of the back in female rats to present to genitals in mating
b) The male will show lordosis because that is an activational effect of oestrogen and they have no testosterone to prevent them acting like a lil bitch
If you give young rats the wrong sex hormones throughout their development they will display behaviour of the opposite sex. True or false?
True.
a) define lordosis
b) what happens when male rats with their genitals removed are injected with oestrogen?
a) Arching of the back in female rats to present to genitals in mating
b) The male will show lordosis because that is an activational effect of oestrogen, and they have no testosterone to prevent them acting like a lil bitch
Define CAIS (congenital androgen sensitivity syndrome).
The baby is genetically a male, with XY chromosomes, but is insensitive to male sex hormones so is morphologically a female.
Define CAH (congenital adrenal hyperplasia).
The adrenal glands overproduce many hormones, thus upsetting the HPA axis.
One of the hormonal groups over-produced are the androgens, so female babies are born with masculinised characters.
What can be said about the a) sexual identity and b) sexual orientation of female CAH sufferers?
a) Slightly diluted female identity
b) More likely to identify as a lesbian
Define 5-ARD (5-alpha reductase deficiency).
5-alpha reductase coverts testosterone to DHT. DHT is required for the development of male sexual organs. Male 5-ARD sufferers are born with ambiguous genitalia. The genitalia become masculinised at puberty instead.
What happens to female 5-ARD sufferers?
Nothing: DHT has no known role in female sexual development.
In 5-ARD it appears morphological sex is changeable. Is sexual identity?
No.
Define 5-ARD (5-alpha reductase deficiency).
5-alpha reductase coverts testosterone to DHT. DHT is required for the development of male sexual organs. Male 5-ARD sufferers are born with ambiguous genitalia. Children sometimes have a female identity but the genitalia become masculinised at puberty. Sometimes this causes a reversal of identity.
Are there male and female differences in the brain?
Yes: in rats they found sexually dimorphic nuclei in the hypothalamus.
In the human brain, sexually dimorphic grey matter has been identified. How?
Different areas of the brain were active during the same tasks in men and women. They found this was correlated to foetal testosterone.
