Lecture 8? Human reproductive ecology 2 Flashcards
(43 cards)
What is the pathology paradigm
- human reproduction has a fundamental paradox: although it is critical to the survival of the species, the process is relatively inefficient
what is an alternative view to the pathology paradigm
adaptationist paradigm
what is the adaptationist paradigm
reproductive losses are not reproductive failures
- suppression mechanisms -> regulate timing of reproductive events
true or false - all conditions are equally good to invest in reproduction
false - the ability to interrupt reproduction can provide a selective advantage
preventing reproduction during inauspicious times is hypothesized to allow females to focus resources on
- surviving bad times
- help existing offspring survive
- avoid investing in offspring with reduced fitness prospects
- improve overall condition to invest in future offspring
What is Peter Ellison’s view on reproductive function
energy as ultimate modulator of reproductive function
What is Peter Ellisons model of reproductive function and energy
social environment, constitutional genetic factors, and physical environment interact and lead to energy availability –> reproductive function
The probability of conceiving, delivering and raising a child can be reduced at different stages
- pre-conception behaviour (coitus avoidance)
- anovulation - not releasing an egg/not ovulating
- miscarriage
- post-conception behaviour (neglect, abandonment, infanticide)
What do progesterone and estrogen do
thicken uterine lining
What are proximate explanations of fecundity when energy balance is positive
positive energy balance leads to greater insulin and greater fat storage and greater ovarian function
What are proximate explanations of fecundity when energy balance is negative
negative energy balance leads to increased cortisol and lower fat storage and decreased ovarian function
what is energy status
stored energy
what is energy balance
intake - expenditure
what is energy flux
energy turnover (bank analogy)
seasons are…..
a good predictor of energy availability and expenditures
in a small village in rural Poland fall and winter months characterized by
- low physical demands, no agricultural work
- harvest and haying in summer, greater expenditure
- progesterone levels lower in summer - ovarian suppression
who is Wenda Trevathan
- evolution of human birth process and its consequences
When did bipedalism emerge
6-4 mya in homininds
- positive selection for bipedalism =changes in how give birth
what is sagittal plane
cut someone in two equal halves
what is coronal plane
cut someone into front and back halve
what is transverse plane
cut someone at centre
what is the birthing process in quadrupeds
- entrance and exit of birth canals are oriented front to back (sagittaly) (similar in primates)
birthing process in humans
- birth canal twisted in middle
- inlet is broadest in transverse and outlet is in the sagittal
- maximum breadths of entrance and exit of
birth canal are perpendicular to each other - human infant head largest in sagittal, shoulders broader in coronal
- pelvic’s inlet and outlet planes are perpendicular
*head rotations
What would be the risks for human babies if mothers adhere to standard primate birthing process
- break neck
