Chapter Thirteen: The Evolution of Social Behavior

Question 1

conspecific cooperative group that extends beyond sexual behavior

Answer 1

society

Question 2

six costs of sociality

Answer 2

1. greater conspicuousness of clumped individuals to predators
2. greater transmission of disease and parasites among members
3. more competition for food among members
4. time and energy expended by subordinates in dealing with more dominant companions
5. greater male vulnerability to cuckold
6. greater female vulnerability to egg tossing, egg dumping, and other forms of reproductive interference by others

Question 3

six benefits of sociality

Answer 3

1. defense against predators via the dilution effect or mutual defense
2. opportunities to receive assistance from others in dealing with pathogens
3. improved foraging via the information center effect
4. subordinates are granted permission to remain safely within the group
5. opportunity for some males to cuckold others
6. opportunity to toss the eggs of others, to dump eggs in others’ nests, and to interfere with rivals’ reproduction

Question 4

every cost of sociality can also ___

Answer 4

be a benefit

Question 5

natural selection predicts that animals should behave ___

Answer 5

selfishly

Question 6

shared gain of direct fitness

Answer 6

mutualism

Question 7

mutualism can cause sociality because ___

Answer 7

both individuals immediately benefit

Question 8

delayed gain of direct fitness

Answer 8

reciprocity

Question 9

in reciprocity, one individual benefits ___ and the other individual benefits ___

Answer 9

now
later

Question 10

two things that have to occur for reciprocity to work

Answer 10

1. pairs must persist long enough to permit payback
2. donors must recognize cheaters so they do not continue to help them

Question 11

an individual that you help that does not help you back later on

Answer 11

cheater

Question 12

number of offspring that survive to reproduce

Answer 12

direct fitness

Question 13

number of non-descendant kin that are born and survive to reproduce due to your actions

Answer 13

indirect fitness

Question 14

direct fitness + indirect fitness

Answer 14

inclusive fitness

Question 15

acting in a way that potentially reduces direct fitness but increases indirect fitness by helping close kin

Answer 15

altruism

Question 16

a permanent loss of direct fitness with potential gain for indirect fitness

Answer 16

obligate altruism

Question 17

temporary loss of direct fitness with potential for indirect fitness gain followed by personal reproduction

Answer 17

facultative altruism

Question 18

natural selection favoring traits that increase indirect fitness more than the resulting decrease in direct fitness

Answer 18

kin selection

Question 19

probability that two individuals possess the same allele because they inherited it from a common ancestor

Answer 19

coefficient of relatedness (r)

Question 20

3 steps for calculating r

Answer 20

1. count paths that separate the two individuals in a family tree
2. raise 1/2 to the number of paths
3. if there are more than one continuous paths, calculate each and then add them together

Question 21

r for parent to child

Answer 21

1/2

Question 22

r for full siblings

Answer 22

1/2

Question 23

r for half siblings

Answer 23

1/4

Question 24

r for grandparent to grandchild (full)

Answer 24

1/4

Question 25

r for nephew/niece to uncle/aunt (full)

Answer 25

1/4

Question 26

r for full cousins

Answer 26

1/8

Question 27

three characteristics of a eusocial group

Answer 27

1. contains multiple generations
2. cooperative brood care (help each other care for young)
3. specialist castes (groups) of non-reproductive individuals

Question 28

the majority of eusocial groups are ___

Answer 28

haplo-diploidy

Question 29

in hallo-diploidy groups, one gender is ___ and the other is ___

Answer 29

haploid
diploid

Question 30

hallo-diploidy groups lead to ___ r values

Answer 30

high

Question 31

haplo-dilpoidy sisters are more closely related to each other than they are to their own offspring, so they increase their inclusive fitness by ____

Answer 31

helping production of sisters rather than production of their own offspring

Question 32

diploid species can also show eusociality if they are very ___

Answer 32

inbred

Question 33

eusociality has only evolved in groups that ___ and ___, but not all groups with these characteristics are eusocial

Answer 33

build complex nests
care for young for a long period of time