13. Family Conflict Flashcards
What are the three common types of conflict between family members?
Parent v Offspring
Sibling competition
Parents - sexual conflict
Why does parent offspring conflict occur?
Parents value all offspring equally, whereas offspring value themselves over their siblings
What does Trivers’ model predict about the age of the mother and the POC?
That the younger the mother the greater the POC - she has more (future) children to want to save resources for
In what ways is there mother-foetus conflict?
Implantation - placental invasion of endometrium
Placental hormones - tug of war over resources and ‘addiction’ to pregnancy
How do trophoblasts invade the uterine wall?
Blastocysts implant and start to differentiate.
Trophoblast cells invade spiral arteries in the uterine wall.
Remodel arteries by displacing endothelial cells and smooth muscle.
= larger diameter blood vessel that cannot constrict
What are the 3 consequences of trophoblast invasion of the uterine wall?
Foetus gains direct access to mothers blood supply
Volume of blood reaching the foetus become independent of maternal vasculature
Placenta can release hormones directly into the maternal blood stream
What does human placental lactogen (hPL) do?
Acts on maternal prolactin receptors to increase maternal resistance to insulin.
Maternal blood has sustained elevated glucose levels
What is the maternal counter strategy against hPL
Increases production of insulin - if not she will develop gestational diabetes
What is and what causes preeclampsia?
Gestational hypertension - foetus releases hormones which increase maternal blood pressure and force blood flow through the placenta
Why are Nazca booby’s assholes?
The sibling competition is so strong that the eldest chick will often kill their younger sibling
In bi-parental mating systems male and females conflict over…
Mating behaviour of female - mate-guarding
Amount of effort each individual puts into raising young
Why do both parents not just stop investing - then no cost.
Because the investment depends on the investment of other parent. optimum is if both parents invest a middle ground (Houston-Davies model)
Why might parents match their investment to that of their partners?
They may not be able to gather enough information on the offspring’s needs so use partner’s investment as a proxy.
Johnstone & Hinde 2006
