1. Weird observations matter, beyond normative expectations 2. Disrupted binaries reveal variation that wasn’t thought to be possible

Weeks 9 and 10 Flashcards by Sara Richmond

Science is a ____________

social process

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● Heteronormative binaries

limit ___________

LGBTQ community in

STEM

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Limits different viewpoints from

others with ______________

unique experiences

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● Sexual diversity of animals
viewed by_____________ can leave interesting
observations unexplored

a heteronormative

lens

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_____________ routine assumption of
heterosexuality and associated behaviors,
family structures, life history traits, etc

Heteronormativity:

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___________ assumption and
naturalization of a binary division and
conventional alignment of gender identity and
sex

● Cisnormativity:

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● Consequences of heteronormativity

Normative traits are naturalized, unquestioned, and
unexamined
b. Makes some variation invisible, or the visible
variation is deemed odd

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Same-sex behavior occurs in _______________

of mammal and bird species

~15-30%

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IN ● Reptiles: Male garter snakes can

emit ____________

female pheromones

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New hypothesis: __________________
○ “Maybe embryos use early hatching to get away from
snakes, but animals in the water select against early
hatching while tadpoles are more likely to be eaten”

● Escape-hatching behavior

adaptive plasticity and hatching
timing

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● Herpetologists considered hatching as a
developmental event, not behavioral
● However, ___________

there is indeed an environmental

stimulus that causes early hatching!

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_____________ suffocate under water

Terrestrial eggs:

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___________ dry out on land

Aquatic eggs:

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Hourglass tree frogs evolved to

lay terrestrial

eggs (ancestors had aquatic eggs)

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● Boundary between terrestrial and aquatic is

____________

more permeable than previously thought

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experiments revealed_____________________ between terrestrial and aquatic egg laying

plastic behavioral

choices

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Male glass frogs known to

brood and guard eggs

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Experiments revealed that hydration

from female frogs

sitting on eggs
provided essential protection from
predation and drying

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● Changed perspective: now know that

________________

ALL glass frogs have and need
parental care
○ Female and male biparental care are
widespread
○ No sex bias in care duration or level of
protection

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Takeaways

Weird observations matter, beyond normative expectations

2. Disrupted binaries reveal variation that wasn’t thought to be possible

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what are the organizational effects from genes

usually involves the SRY gene

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Y chromosome sry gene → testis → testosterone →

__________

male phenotype

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XX chromosomes → absence of hormones →

_____________

female phenotype

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■ Estrogen feminizes during _________

puberty

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Activational effects from _________

adult steroids

● Environmental socialization (nurturing) leads to gender ___________

○ Arises from sex

Rats: affected by perinatal hormones ○ Blocked aromatase around time of birth ○ Males had preference for ___________

control males

● __________________ | ○ Overproduce androgens

Congenital adrenal hyperplasia (CAH)

○ Males born w/o genitals, transformed into female with surgery ○ Male typical sexual attraction

● Cloacal/Vesical Exstrophy

○ Higher incidence of __________ in CAH females indication that Endocrine modifications impact _________

homosexuality sexual orientation

Other modifications: ○ Androgen insensitivity, 5a-reductase deficiency, Treatment of mothers with DES, Various chromosomal anomalies the show that _________________

Possible organizational effect from hormones → affects | sexual orientation

what are the two sex differences linked to homosexuality

- digit 2:digit 4 | - long bone length

____________ | ● Ratio is decreased (masculinized) in homosexual women

Digit 2: Digit 4 (2D:4D) ratio

● Growth of bones is influenced by

prenatal T

have a smaller 2D:4D ratio

● Males

Long bone width/length ratio | _______ have larger hand width/length ratio

● Males

lone bone ● Ratio is l__________ in homosexual women

larger (masculinized)

Suggests that ___________ is above average for | homosexual women

perinatal exposure/action of T

____________ | ● Sounds given off by inner ear when responding to sound

Otoacoustic Emissions (OAE)

● OAE is higher in number and amplitude in

females than males

● OAE is ___________ in homosexual women

lower (masculinized) i

Brain activation by sexual odors | ● Compounds derived from

androgens or estrogens similar to pheromones

________ activate hypothalamus of straight men

● Estrogens

__________ activate hypothalamus of straight women and homosexual men

● Androgens

● Group of cells in anterior hypothalamus

INAH-3

● Males have ___________

larger INAH-3 than females

_________ INAH-3 in homosexual men

Smaller (feminized)

How did they get exposed to atypical levels of hormones

``` ● Largely unknown ● Hypothesis: ○ Stress ○ Endocrine disruptors ○ Inflammation of brain ```

Genes might participate to control sexual orientation ○ If a family has one homosexual member,_________________ ○ Twin studies: higher concordance of ___________ ● Search for genes has been largely unsuccessful

chance of another one is higher homosexual orientation in identical twins

MAGE-11 (melanoma associated antigen) located at Xq28 (X chromosome) ○ Epigenetically regulated gene that increases sensitivity to __________

androgen (receptor coactivator)

■ Demethylated following androgen deprivation → _________________ ○ Only present in humans and primates: sexual orientation is only a human phenomena

hypersensitivity to androgens

Mage 11 ○ Might show a link b/w

genetic and hormonal controls in the brain resulting in sexual orientation

○ Not the case, so epigenetics, gene expression, or something else could have

a causal role

○ If sexual orientation was due to differences in hormone [ ] and action, we would lots of

ambiguous sexual orientations

________ might help with controlling the sensitivity to testosterone

Epigenetics

______________ Increase incidence of homosexual males to mothers that have previously had other boys

Older Brother Effect

Explanation of the older brother effect is that Mothers develop antibodies for ___________ ○

neurologin 4, a Y-linked protein

Neuologin 4 Accumulate in mother as a result __________ ○ Antibodies affect development of brain ○ Increase incidence of homosexuality

foreign embryo (XY)

Heteronormativity and cisnormativity affect the way we _________________

observe, record, | analyze, etc. data

● Frogs teach us things; not everything follows a

binary

○ Unlikely these phenomena escape biological control and left open to ______

social influence

Observed phenomena suggest there are biological influences to _________ besides social influences ○ Organizational effects of hormones ○ Genetics and epigenetics ○ Older brother effect

sexual orientation

● Sexual orientation is an _______ (when viewed through biologist lens)

evolutionary effect