Chapter 12: Sex and Gender Flashcards
Why are men more vulnerable than women to the senescent effects of pleiotropic genes?
In the EEA, most men died early in life due to accidental or competition induced death. This means that genes which provided an early life advantage, yet provided a later life detriment, were selected solely for their benefit. The outcome of this was that pleitropic, late-occurring detriments were genetically passed on. Now, today, in the modern world, where men live until their late 70s, these effects are being expressed. Men are more vulnerable because genes that encode for things like testosterone production, which prove early-life reproductive advantages, also produce later-life ailments such as cardiovascular disease. Women in the EEA selected against these genes because they did not die due to accidental or competition induced causes1.
How would you best explain child toy preferences (i.e. females like dolls)?
While social pressures are certainly a factor, these are best explained by stating that the sexes have different drives to learn about EEA pertinent skills. Children will place themselves in situations that allow for functional learning opportunities. “Boys learn more about spatial cognition (if indeed our current beliefs about its development are correct) because boys are attracted to the kinds of activities that lead to its development. This is good engineering, designed by natural selection.”
Who provided food in the EEA? Answer generally (as in for the whole tribe), and then for children specifically.
Generally speaking, women contributed up to 60% of food in the EEA. For children, females were the sole source of nutrition in the EEA.
How is sex ubiquitously defined across species?
Sex is defined by gamete size: females have the larger gamete, males the smaller.
Explain the concept of mitochondrial and chromosomal diversity and how it relates to the varied sexual success that we see between sexes.
“In the human population, we have DNA that is inherited only from our mothers that we can compare directly to DNA that is inherited only from our fathers. There is greater diversity of DNA in the mitochondrial DNA (mom’s DNA) than in Y chromosome DNA (dad’s DNA), which is consistent with the idea that there is greater variance in reproductive success in males than females.”
What is your best explanation for why most complex adaptations are universal? What implications does this have for people from opposite sides of the world?
“…complex designs are built by a series of single mutations being selected for: One very small change, mediated by one beneficial mutation, becomes universal in the species, followed at some point by a new change, caused by a new beneficial mutation, becomes universal in the population, etc.” “The implication is that people everywhere have the same adaptations, whether they develop in Africa, Asia, or the Americas,”
Describe androgen insensitivity syndrome. Some information to include is, who it affects, the mechanisms behind it, and when this abnormality is typically recognized.
This is an X-linked recessive trait that affects those with XY configurations. Baby produces both testosterone, which does not have androgen receptors to bind to, and Mullerian-inhibiting hormones, which atrophy the fallopian tube and ovaries. Functionally, the male is left to follow the default strategy of femininity. This condition is noticed when menarche should typically occur—the person does not get their period.
Using a habituation paradigm we can learn when infants begin to discriminate between male and female faces. What is this age, and what is a commonly reported issue with this methodology?
“…infants can discriminate male and female faces by 3 to 4 months, but the dishabituation was over-shadowed by a preference to look at the gender of their primary caregiver.” For test questions sake, know this: “if they were habituated to a female face, they did not dishabituate to a male face because most infants actually preferred to look at female faces.”
Describe Turner’s syndrome. What are the mechanisms behind it, how does the person develop, and how can the condition depending on which parent provides the chromosome(s)?
People with Turner’s syndrome are born with a single X chromosome. This can be provided by either the mother or father. Male methylated X chromosomes—from mothers—produce male-typical behaviour in females Female methylated X chromosomes—from fathers— produce normative, female-typical outcomes. Develop as a female, but may require exogenous estrogen for normative growth.
When is the earliest estimate for the development of gender stereotypes?
Eighteen months.
Describe congenital adrenal hyperplasia. Some information to include is, who it affects and the mechanisms behind it.
Most common intersex condition in people with XX configurations. During prenatal development the child’s adrenal gland will produce an excessive amount of androgens leading to male-typical characteristics: enlarged external genitalia and a male-like cognition.
Describe the types of aggression most commonly seen amongst males and females.
Males engage in physical aggression; females engage in relational aggression.
What natural test do we have of gender socialization theory?
The case of the Reimer twins, where despite being raised as a female, Bruce Reimer did not fit in as nor feel like one.
Female infants perform more prosocial actions. What evidence do we have for this?
Six weeks: Females show more social smiles. Three months: Females engage in more face-to-face communication. *Twelve* to twenty months: Females show more distress when another person is injured (empathy).
Describe 5-Alpha-Reductase deficiency. Some information to include is, who it affects, the mechanisms behind it, and when this abnormality is typically recognized.
Affects people with an XY configuration. 5-alpha-reductase converts testosterone to active dihydrotestosterone. A deficiency leads to poor conversion. Males appear female, with female genitalia, until puberty, when the testosterone rush creates a male phenotype.
What are three pieces of evidence for gender socialization theory?
1) Children will watch same-sex models more than opposite-sex models. 2) Parents at a science centre are three times more likely to explain the exhibit to their son than they are their daughter. 3) People will respond differently to the same infant depending on how it is dressed (indicating its gender).
At this age, we assess parental investment in our environment and alter our pubertal timing around it. What is this age, and how can it change pubertal timing?
Five to seven years. In a low-investment society, puberty will initiate earlier to maximize reproductive time. This limits the time that a child has in the growth phase.
