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Terms in this set (49)
mostly _____, ______ and ______ are social
cetaceans, carnivores and primates
most mammal social groups are matraminial
based off of the mother. mother offspring and closely related females (sisters, aunt, nieces) make the social group, males disperse when they become sexually mature
social cooperation: alarm calling
altruistic behavior--> recipients of behavior benefit from the behavior, but the provider has a cost. provider has made themselves evident to the threat. benefits the recipients but not the provider. social group benefits but the individual doesn't
social cooperation: cooperative rearing of young
communal care. adults take care of offspring so that individual parents don't have to spend time and energy doing it.
females all go into birth at the same time. most females are lactating so they can feed any of the offspring, not just their own. by having more milk available, the offspring are benefiting. parents are benefiting because offspring are more likely to survive by this.
subordinate females show suppressed breeding, won't breed every year. only dominant females breed. subordinant females guard young.
hormonally theyre pregnant, but no embryo. lactation can result.
social cooperation: coalitions
-individuals within a group work cooperatively together. social cooperation can lead to coalitions.
-in order for a coalition to be advantageous, the duration of coalition has to be long
-mammals have varying time frames for these.
social cooperation: eusociality
truly social mammal
in order for true sociality to occur→
there has to be a certain number of traits being demonstrated by the individuals in that group
traits for true sociality to occur
1.) cooperation in care of the young. all or most of the adults will be involved in the caring of the young
2.) reproductive casts. not all members of the group are going to be reproducing. members not reproducing are helping care for those that are not reproducing. not for offspring
3.) has to be an overlap of generations. have the offspring from first mating help out the parents during the second mating. assist with parents and siblings
benefits of group living: protection from physician factors
bats can keep eachother warm, conserve energy
bats in the center are warm.
benefits of group living: protection from predators
-Detection of predators is more rapid in groups because there are more individuals paying attention.
-increase in the deteruance of predadation: group defense, mobbing, chasing.
-each individual within the group is spending less time on their own and more time on nursing, feeding, care. beneficial to the group to have more people
many eye hypothesis
predator looking and there are more than one set of eyeballs looking at you, the likilihood of a predator being detected is much higher when there is a group.
benefits of group living: food acquisition
-increase acquisition of food for the group. groups will find food more easily than individuals.
-once they find food, greater chance of obtaining the prey and obtain larger prey than if they were alone.
benefits of group living: resource defense
Social behavior is common in carnivores, wolves, african hunting dogs: territorial
by having groups, they can defend their territory and resources a lot better. wealth of resources is better protected.
African hunting dogs
when two packs meet to fight, the largest pack always wins
benefits of group living: division of labor
casts: some are reproductive, guards, nurturers, food gatherers.
one individual just does one part of the task. daily expenditures reduced
benefits of group living: improved learning
young learn from parents, witnessing what other people do. long nurturing process where offspring are maintained with parents overtime as they develop these behaviors
group learning causes an _____ in learning, but it requires a very long period of physiological and psychological dependence. have to be apart of that group for a long time and be dependent on the group. learn more skills than if you were part of a small family.
cost of group living: increased competition
for resources or mates. whatever resources are available, the group has to share. might not want to share equally. only a few gain access to resources.
cost of group living: disease/parasitism
disease and parasitism increases in groups. increased size of groups increases the ability of diseases to spread from one individual to another. the disease will be transferred more rapidly
cost of group living: reproductive suppression
as group sizes increase, reduction of individuals that will reproduce. dominant individuals will be reproducing.
misdirected parental care
some females will nurture offspring but offspring are not related to them at all. hundreds of bats flying out and back into the cave and they look the same so females take care of young that they thought were a niece or nephew but instead its an unrelated bat. inclusive fitness reduced because its investing time in a bat not related.
groups have limited resources, more aggression within these groups. young are killed sometimes accidentally. competition, trampelled.
group selection: behaviors evolve for the good of the group, not necessarily for the good of the individual
-agued against group selection.
-since behavior is produced by an individual the explanation has to be at the level of the individual.
-even if that behavior is in a group is produced by an individual the explanation for that behavior has to be at the level of the individual. Individual has to be the one benefitting somehow.
-the group may benefit, but the groups goal is not the goal of the individual that is engaging in that behavior.
G. C. Williams
argued that researchers should assume natural selection opperates only at the level that is necessary to explain the facts, and no higher. a group selection argument usually will not hold weight because in order to create a group selection argument u have to say that this happened and this happened and this is benficial bcuz of all this which is opposite on the law of occams razor
explain things at the lowest level possible that we will be able to explain things at.
williams is looking at a lot of these group like behaviors and sees that most of these behaviors that we see as group advantageous things are operating at the level of parents and offspring. these social things are done to increase the likelihood of survivability of the offspring, which benefits the parents. if that's the case, there should be genes promoting selfish behavior. these genes should swamp out any genes promoting altruisim.
if you have behaviors that are totally altruistic, genetically they don't stand a chance if behaviors where individual directly benefits. inability of group type explanations to persist.
W. D. Hamilton
kin selection explains why altruisms is happening because recipeients are related to you
selfish herd theory
each individual attempts to reduce the chances of being caught by predators, by being part of a group. The altruisim within a group is beneifting the indivudla because that indiviaul finds excessive safety.
--if individuals within that group just happen to be related, its better to be apart of group because the vigulence in altruistic act should increase because of genetic realtionship there. a lot of stuff interplayin gin here.,
b/c > I/r
if altruist more than doubles its reproductive fitness of the sibling, by some sort of altruistic act, then genes that promote that behavior should spread. see kin selection is based on a lot of math.
biggest problem with Hamiltons rule
how do individuals know in a split second period of time who the kin are and who the kin aren't.
green beard effect
if you possess a green beard, then it would be easy to see anyone else who has a green beard. those that have it are more like you, mechanism for recognizing related individuals. mammals use an olfactory due. easy to recognize and can tell those that are related to you and those that are not
raised with sam litter mates, you know those individuals well. behavior is different than a non-related individual
what explains how kin selection works
individuals with the same gene possess some sort of mechanism to determine one another.
somewhat violating explanation for polymans razor because it has a degree of relaitonship, not all groups have individuals related to one another.
R. L Trivers
behavior that benefits another with the expectation that those benefits will be returned in the future
reciprocal altruism will only last if
bats that stayed behind will fly out in the future, if they never go out, they'll never give you food. you're a cheater
natural selection acts on level of individuL
produces altruistic behavior because individual performing this behavior will benefit
in order for reciprocal altruism to occur
-interaction between individuals has to be a long one.
-has to be a low dispersal rate, have to stay together for a long period of time.
-dependence on mutual care, whole group is social and will care for eachother.
as cheating increases,
the amount of altruistic action will decrease within the group. cheating thing is not something that gets minted in populations for a long period of time
there is a strategy that natural populations will develop. if it engages in this behavior this way, the populations will benefit the best.
tit for tat
involves playing cooperatively at first, then doing whatever the other player did in the previous period. environmental stable stategy for all natural populations with repeated interactions
both immediately benefit from behavior with no cost to the other.
social behavior could have these actions: huddling in the cold, both individuals stay warm. communal hunting: more prey, bigger prey
in some situations, the behaviors don't have to have a cost
R. D. Alexander
in conflicts between parents and offspring, parents should always prevail. behaviors within a group should always increase the fitness of the parents.
winner will always be the parents. parents can limit care to be equal to all of the offspring
parents can withhold care when resources are inefficient. parents can take care of themselves and not the offspring
parents can kill or eat their offspring: infantiside.
parents can influence the behavior of offspring to get them to help.
ex. ) naked mole rat: female causes permanent sterility in her daughters so that shes the only one that is mating
S. T. Emlen
ethological constraints model
ethological constraints model
in cooperative populations, the environment plays a critical role in promoting cooperative behavior. so the environment that has ready supplies of things, social behavior could evolve in groups that have abundances or shortages. environment is playing a huge role, not just genetics, reproductive output, etc.
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