Chapter Thirteen: The Evolution of Social Behavior Flashcards
conspecific cooperative group that extends beyond sexual behavior
society
six costs of sociality
- greater conspicuousness of clumped individuals to predators
- greater transmission of disease and parasites among members
- more competition for food among members
- time and energy expended by subordinates in dealing with more dominant companions
- greater male vulnerability to cuckold
- greater female vulnerability to egg tossing, egg dumping, and other forms of reproductive interference by others
six benefits of sociality
- defense against predators via the dilution effect or mutual defense
- opportunities to receive assistance from others in dealing with pathogens
- improved foraging via the information center effect
- subordinates are granted permission to remain safely within the group
- opportunity for some males to cuckold others
- opportunity to toss the eggs of others, to dump eggs in others’ nests, and to interfere with rivals’ reproduction
every cost of sociality can also ___
be a benefit
natural selection predicts that animals should behave ___
selfishly
shared gain of direct fitness
mutualism
mutualism can cause sociality because ___
both individuals immediately benefit
delayed gain of direct fitness
reciprocity
in reciprocity, one individual benefits ___ and the other individual benefits ___
now
later
two things that have to occur for reciprocity to work
- pairs must persist long enough to permit payback
- donors must recognize cheaters so they do not continue to help them
an individual that you help that does not help you back later on
cheater
number of offspring that survive to reproduce
direct fitness
number of non-descendant kin that are born and survive to reproduce due to your actions
indirect fitness
direct fitness + indirect fitness
inclusive fitness
acting in a way that potentially reduces direct fitness but increases indirect fitness by helping close kin
altruism
a permanent loss of direct fitness with potential gain for indirect fitness
obligate altruism
temporary loss of direct fitness with potential for indirect fitness gain followed by personal reproduction
facultative altruism
natural selection favoring traits that increase indirect fitness more than the resulting decrease in direct fitness
kin selection
probability that two individuals possess the same allele because they inherited it from a common ancestor
coefficient of relatedness (r)
3 steps for calculating r
- count paths that separate the two individuals in a family tree
- raise 1/2 to the number of paths
- if there are more than one continuous paths, calculate each and then add them together
r for parent to child
1/2
r for full siblings
1/2
r for half siblings
1/4
r for grandparent to grandchild (full)
1/4
r for nephew/niece to uncle/aunt (full)
1/4
r for full cousins
1/8
three characteristics of a eusocial group
- contains multiple generations
- cooperative brood care (help each other care for young)
- specialist castes (groups) of non-reproductive individuals
the majority of eusocial groups are ___
haplo-diploidy
in hallo-diploidy groups, one gender is ___ and the other is ___
haploid
diploid
hallo-diploidy groups lead to ___ r values
high
haplo-dilpoidy sisters are more closely related to each other than they are to their own offspring, so they increase their inclusive fitness by ____
helping production of sisters rather than production of their own offspring
diploid species can also show eusociality if they are very ___
inbred
eusociality has only evolved in groups that ___ and ___, but not all groups with these characteristics are eusocial
build complex nests
care for young for a long period of time
