Kin Selection & Social Behavior

Question 1

recipient benefits & actor benefits

Answer 1

cooperation (mutualism)

Question 2

recipient benefits & actor is harmed

Answer 2

alturism

Question 3

recipient is harmful & actor benefits

Answer 3

selfishness

Question 4

recipient is harmful & actor is harmed

Answer 4

spite

Question 5

Darwin suggestions about selection

Answer 5

selection could favor altruistic behavior if those benefitted close relatives

Question 6

inclusive fitness =

Answer 6

direct fitness + indirect fitness

Question 7

direct fitness

Answer 7

personal reproduction

Question 8

indirect fitness

Answer 8

the additional reproduction by relatives that is made possible by an individual’s actions

Question 9

kin selection

Answer 9

natural selection favoring the spread of alleles that increase indirect fitness

Question 10

inclusive fitness is mediated by 3 factors

Answer 10

r = relatedness
B = the benefit to the recipient
C= the cost to the actor

Question 11

Hamilton’s Rule

Answer 11

Br - C > 0 or Br > C

Question 12

calculating r: sibling to sibling

Answer 12

1/2

Question 13

calculating r: first cousins

Answer 13

1/8

Question 14

calculating r: parent to offspring

Answer 14

1/2

Question 15

calculating r: grandparent to grandparent

Answer 15

1/4

Question 16

calculating r: aunt/uncle to niece/nephew

Answer 16

1/4

Question 17

kin selection example: praire dogs

Answer 17

• more likely to give alarms when kin is present
• call as frequent in the presence of parents & full sibs as offspring

Question 18

kin selection example: squirrels

Answer 18

• 14 yrs, observed 30 natural predator attacks
• squirrels whistle for hawks, but trill for mammals

Question 19

whistling for hawks =

Answer 19

selfish

Question 20

trilling for mammals =

Answer 20

altruistic

Question 21

eusociality describes social systems with:

Answer 21

• overlapping generations between parents & offspring
• cooperative brood care
• specialized casts of non-reproductive individuals

Question 22

where is eusociality common?

Answer 22

Hymenoptera

Question 23

is there something that predisposes members of Hymenoptera to be eusocial?

Answer 23

haplodiploidy

Question 24

haploid

Answer 24

males develop from unfertilized eggs

Question 25

diploid

Answer 25

females develop from fertilized eggs

Question 26

hymenoptera are _________________

Answer 26

haploiddiploid

Question 27

females maximize their inclusive fitness if they ....

Answer 27

raise sisters

Question 28

consequence of females maximizing their inclusive fitness

Answer 28

because female workers are r=3/4 to sisters & r=1/4 to brothers, they should favor a 3:1 sex ratio

Question 29

does haploidiploidy explain eusociality?

Answer 29

- calculations assume the queen mates once (1 father). but in honey queens, the queen mates with multiple males. so females are less closely related - in many species, >1 queen so many workers are related by r=0 - many haploid species are not eusocial and vice versa

Question 30

eusociality is influenced by ecology & genetics

Answer 30

the evolution of nesting behavior, & the need to supply larvae with food, it makes it difficult for a female to manage a nest by herself

Question 31

naked mole rats

Answer 31

- live underground in colonies - dig tunnel systems up to 2 miles long - ectothermic

Question 32

naked mole rat natural history

Answer 32

- neither moles or rats - eusocial, but with XY genetic system - 1 queen, 2-3 reproductive males - found in desert regions in the Horn of Africa - highly inbred groups

Question 33

how do non-kin cooperate among each other in nature?

Answer 33

individuals can be selected to dispense altruistic acts if equally valuable favors are later returned to the benefactors

Question 34

in reciprocal altruism, two conditions must be met

Answer 34

- cost to actor must be

Question 35

reciprocal altruism most likely to evolve when:

Answer 35

- groups stable & individuals repeatedly interact - many opportunities for altruism - individuals have good memories potential altruists interact in symmetrical situations

Question 36

vampire bat natural history

Answer 36

- social units of 8-12 adult females & their offspring - Costa Rica - roost in tree by day - average r-0.11 among interacting individuals - 33% of juveniles & 7% of adults fail to eat each night