sexual selection Flashcards
when can monogamous biparental care evolve
males contribute to feeding (carnivores)
males carry the young (marmosets)
fertilization mode/parent gender hypotheses
parental certainty (trivers) - external fertilisation means higher male certainty
association (williams) - external laid in male territory/ internal sets stage for embryo retention
hamiltons rule?
individual helps another when: br-c > 0
coefficient of relatedness (r)
Probability that two individuals share a gene because of common decen
why does parent-offspring conflict occur
BENEFITS: any investment by the parent in an offspring increases its chance of surviving to reproduce
COSTS: care in one offspring reduces parental investment in other offspring
tradeoffs in parental investment
offspring quantity vs. quality within a brood
current vs. future brood investment
parental risk taking in north + south american songbirds
NA have large clutch sizes, low adult survival (more food, harsher climate)
SA have small clutches, high survival
game theory model
key to understanding the decisions of one sex is the decisions of the other parent
stable outcome of competition
If all members of a population adopt it, can’t be bettered by alter. strategy
3 conflict types in evolution of parental care
sexual (how much care to provide)
- depends on life history constraints, benefits/costs
sibling rivalry (how much to demand)
- each values itself most
parent-offspring (supply and demand of care)
- individual offspring selected to demand more care than is optimal from parents point of view…resulting in a battleground of conflict
when should individual let sibling have resource
does sibling twice as good as individual
sibling rivalry in swine
teat fidelity and specialised “needle teeth”
sibling rivalry in pronghorn
“siblicide” in utero
sibling rivalry in sand tiger sharks
cannbalism in utero
