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26 Cards in this Set

  • Front
  • Back

consequences of asymmetric limits on fitness

members of the sex subject to strong selection will be competitive

members of the sex subject to weak selection will be selective

intrasexual selection

male-male competition

alternative strategies

the smaller iguanas

smaller iguanas take less time to copulate

advantage to be smaller

alternative strategies

sneaky sex

fish shooting sperm into the water

ex. salmon

alternative strategies

sperm competition

can have clutch/litter with more than one dad

large ejaculations

ex. ladyflies

alternative strategies


males kill offspring from other males

intersexual selection

selection on males

females choice

ex. red-collared widowbirds have long tails despite being a disadvantage

assortive mating

genetic variation in female preference and male display

preferences and variation then passed on to offspring

if pop display matches pop preference...

then pop will not evolve

runaway selection

carries pop away from equilibrium

ex. ants with longer eyestalks win male competitions and females develop preference for longer stalks

choosy female benefits

get better genes for offspring

can receive shelter from male

can receive food from male


female having more than one partner

litter size and # of mother's sexual partners are related

mutualistic relationship

actor = + recipient = +

ex. greater ani birds and communal nests


actor = + recipient = -

ex. cane toads eat each other to reduce competition


actor = - recipient = +

ex. ground squirrels will sound the alarm to warn others


actor = - recipient = -

ex. bacteriocin

direct fitness

fitness contribution from personal fitness

indirect fitness

fitness contribution from relatives that achieve additional repro success due to altruistic behavior

inclusive fitness

direct fitness + indirect fitness

kin selection

natural selection favoring the spread of alleles that increase the indirect component of fitness

increased fitness of close relatives must....

decrease personal fitness to be darwinian

can show alleles favoring altruism can spread using relatedness

hamilton's rule

(benefits to recipient)x(relatedness)-(cost to actor) > 0

greenbeard effect

allele induces altruism toward others that have same allele (gives visible trait)

requirements for greenbeard effect

1. allele must cause the trait

2. recognize the trait in others

3. act altruistically toward that other

multilevel selection

an evolutionary process in which selection acts at multiple levels


behavior that is beneficial or costly to the actor and beneficial to the recipient and selected for at least in part because recipient benefits

can be selected for when higher productivity of groups w/ cooperators outweighs the lower relative fitness of cooperators themselves