Kin Selection Flashcards
what is behavioral ecology?
survival value and reproductive potential of behaviors
what do we expect from evolution?
that there will be natural selection of behaviors that benefit survival
how can ecology effect behaviour?
the best behavior depends on the ecology eg distribution of food
why study from a phenotypic perspective?
shows long term evolution. genetic models get stuck at evolutionary dead ends without adapting to new environments.
outline the streetcar theory of evolution.
- each trait governed by several different genes
- evolution hits road blocks
- resumes when mutations introduce new genetics
- can look at phenotypic evolution
what do we expect from direct fitness?
that one individual outperforms another, expect selfish individuals
what goes against classical evolution?
cooperation and altruism
why is altruism hard to explain?
one individual helps another individual but at a cost
what is altruism?
any behavior that is costly to the reproduction of the actor but beneficial to the recipient
what is cooperative breeding?
off spring receive help from additional group member (helpers)
what is group selection?
selection happening at a group level - individuals doing things for the good of the group. if they have cooperators and altruists may do better as a whole.
what is are some problems of group selection?
- mutations that are not cooperative
- has to happen at the same rate for it to work
- kin selection can explain everything that group selection can
what will happen if there are mutations that are not cooperative?
an individual will be receiving help but no helping others - they’re doing better and will increase
what is kin selection?
helping individuals that are related to you
how can altruism be explained by kin selection?
altruism ensures the improved transmission of genes as long as the individual being helped is related. it will help there survival or reproductive success and the altruism gene propagates
explain parental care?
direct fitness. maximizes their genetic contribution to future generations.
what is the coefficient of relatedness?
genetic similarity between social partners relative to the rest of the population
what is the actor?
doing the behaviour
what is the recipient?
being helped
what is inclusive fitness?
direct fitness and indirect fitness - the actor will get rx the extra offspring
what is Hamilton’s rule?
theory - knowing when an individual should help/not help a relative
what can happen if family members help each other to survive?
gene proliferation
- the gene causing altruistic behavior could increase in frequency
outline the equation to go with Hamilton’s rule
B/C > 1/r
what does Hamilton’s rule equation predict?
when altruistic acts will be favored by selection
what is an alternative form of the equation?
B/C > (r actor to own offspring)/(r actor to recipient offspring)
what is r?
r = coefficient of relatedness
what is B?
b= benefit to recipient
what is C?
c = cost to actor
what does the second form of the equation need to be used?
when looking at haplo - diploid family trees
what happens when breeding territories are limited?
- c can be close to 0
altruism pays when an individual can’t find breeding territory on their own
describe Belding’s ground squirrel as evidence for kin selection
- Unrelated ground squirrels kill each other’s offspring - relatives do not
- Their alarms are given only when relatives are nearby
what does sibling rivalry cause?
parent offspring conflic
why does sibling rivalry and parent offspring conflict occur?
- siblings want to out compete each other
- parent wants them both to do well
- offspring want to manipulate the parents
where have studies found there is increased selfishness?
- when brood mates are more likely to be half siblings
- compared begging displays of species of passerine birds
how are humans evidence of kin selection?
- older kin encourage younger kin to behave more altruistically toward each other
- grandmothers invest more in grand-offspring than grandfathers
- maternal grandmothers invest more than paternal grandmothers
how can hamiltons rule explain spite?
- in spite C is positive and B is negative
- means that r needs to be negative
- means that the recipient is less related to the actor than the average population is
who is spite aimed at?
- those who are unlikely to share the spite gene
- those who are furthest away genetically
- harming those who compete with relatives helps relatives
outline the green beard hypothesis
- green beard genes are unlikely to be common because they can be out competed by false beards
- green bears are like altruistic traits
- individual can take the cost but not receive the benefit
- can be tricked
what are the different forms of kin recognition?
- treat anyone in the home as kin
- those you grow up with are kin (form of imprinting)
- partly by learning and partly by ‘phenotype matching’
give an example of kin recognition in female ground squirrels
- use odors from oral and dorsal glands as a cue of relatedness
what happens if kin discrimination is not possible?
- behavior evolves in response to the average relatedness between interacting individuals
what could be the result of limited dispersal?
could lead to a high relatedness locally and this would favor indiscriminate altruism (without kin discrimination)
