Social behaviour

Question 1

what is social behaviour

Answer 1

activities among members of the same species

that have fitness consequences on the focal individual and others in the group

Question 2

3 spatial variation types

Answer 2

clumped
e.g. herds, flocks etc

uniform
e.g. nesting territories

random
e.g. trees

Question 3

what is a group

Answer 3

a social construct between spatial aggregated participants

Question 4

which 3 rules govern complex movements?

Answer 4

individuals watch the whole flock and adjust their behaviour to the whole flock

each individual watches 6-7 nearest neighbours + coordinates with them

individuals differ
- there are leaders + followers

Question 5

what are the 3 patterns that can emerge from simple individual rules?

Answer 5

repulsion

orientation

attraction

Question 6

opinion polling

Answer 6

individuals make choices and can recruit others to their choice
e.g. nest choosing in bees, ants, gorillas

Question 7

opinion polling

- nest choosing in ants

Answer 7

scouts can lead a recruit to a new site
-> if a recruit approves it, they can lead a new recruit

at a critical point
- enough recruits are at site to switch from leading behaviour to transport behaviour
(= rates of movement increase + nests are transported + established)

Question 8

benefits to individuals in the group
- antipredator

• foraging

Answer 8

dilution
confusion
defence
vigilance

better finding
better capturing

Question 9

diluting the predation probability

Answer 9

via masting/swamping
or selfish herds

the more in your group, the less likely your individual predation
(if attack rate is constant)

Question 10

masting

Answer 10

when you have an overproduction of progeny in a v limited amount of time

• predators can’t keep up
• > mass increase in prey

Question 11

selfish herds

Answer 11

you need to be further away from the predator than your neighbour

predation isn’t easily distributed across groups
-> probably attack the closest individual

e.g. seals attack crowd of penguins

Question 12

confusing predators

Answer 12

as group increases in size

• > predator gets more confused, distracted + can’t focus on an individual
• > successful attacks decrease

Question 13

defending against predators

Answer 13

by deterring attack e.g. shore birds mobbing gulls to increase their reproductive success

or using formations

Question 14

vigilance

Answer 14

some birds have their heads up and watch
-> so others can do other things e.g. eat

individuals in group must monitor the alert behaviour of others in the group
- so can know if predators are detected

Question 15

better finding food

- hypothesis

Answer 15

Information Transfer Hypothesis
- as food quality + quantity increases
they make more noise

SO a group increases the efficiency of finding food via a network

Question 16

better capturing

Answer 16

hunting in groups means you can catch prey much bigger than you

Question 17

costs to individuals in a group

• foraging
• risks

Answer 17

-risk of losing
-prey
sharing

• cost of defence
• cost of vigilance
• parasitism

Question 18

parasitism

Answer 18

the larger the colony, the more parasites they have + lower individual body mass

Question 19

sharing

Answer 19

the bigger the group size, the lower the relative food intake rate

Question 20

optimal group size

Answer 20

can be unstable when individual foragers continue to join a group

• beyond optimum group size = fitness falls
• eventually reaching similar levels as in small foraging groups

-> social foraging provides little evolutionary advantage

Question 21

3 types of social behaviour studying

Answer 21

brain sciences + sociogenomics

sociobiology

sociophylogeography

Question 22

what is…
sociogenomics?

sociobiology?

sociophylogeography?

Answer 22

what an individual does is influenced by its brain, physiology and genes

investigating individuals within the population

selection produces differences between populations + species

Question 23

define altruism

Answer 23

individuals give up resources to benefit their neighbours at a cost to themselves

Question 24

2 ways of modelling social interactions

what is mathematically important about these models?

Answer 24

inclusive fitness approach

multilevel selection approach

they’re mathematically equivalent

Question 25

inclusive fitness approach

Answer 25

focuses on how an actor affects the fitness of others

• direct + indirect relatedness measures the value of the recipient in transmitting copies of the actor’s own genes
• > leads to a gene-centred view of evolutionary change

Question 26

multilevel selection approach

Answer 26

focuses on social evolution in terms of selection within group and between groups

overall population will be removed if its below a level of fitness

Question 27

Hamilton’s rule

Answer 27

a gene invades if rB > C

Question 28

what is a greenbeard?

Answer 28

a gene in 1 individual generates a phenotype
that causes the actor to:
help those showing the same phenotype or harm those that don’t

-> drive that gene to fixation

Question 29

greenbeard:
facultative helping

obligate helping

Answer 29

only help other greenbeards

greenbeards help everyone in population BUT only greenbeards benefit

Question 30

greenbeards:
facultative harming

obligate harming

Answer 30

only harm non-greenbeards

harm everyone
BUT greenbeards with the same gene can protect themselves from harm

Question 31

multilevel selection

- explain

Answer 31

cooperators have a within-group disadvantage against cheats
-> leads to -ve within-group selection component

BUT groups with more cooperators are more productive
-> leads to +ve between-group selection component