The evolution of social behaviour

Question 1

What is social behaviour?

Answer 1

Behaviour directed towards members of the same species.

Question 2

What are the 4 types of social behaviour? Differentiate them.

Answer 2

1. Subsocial: live and chill together, raise each other’s young.
2. Quasisocial: co-operative brood care, one gen, no division of labour
3. Semicociality: co-operative brood care, one gen, division of labour, castes not morphologically different
4. Eusociality: castes morphologically different

Question 3

What are the 2 types of subsociality?

Answer 3

1. Subsocial aggregation: Group living due to mutual attraction and benefit
2. Subsocial parental care: parental behaviour that promotes the survival growth and development of offspring (no nesting, solitary nesting, communal nesting)

Question 4

What are the benefits of living in a group?

Answer 4

1. Reduced risk of predation
2. Improved foraging opportunities
3. Learning and cultural transmission (learn from parents)
4. Improved offspring survival (co-operative breeding)
5. Conserving heat and water (huddling)

Question 5

What is the selfish herd hypothesis?

Answer 5

More animals will try and stay in the centre of the pack to be at less risk of predation.

Question 6

How does living in a group reduce the risk of predation?

Answer 6

1. Increased vigilance: Many eyes hypothesis

2. Predator dilution: selfish herd hypothesis

Question 7

How does living in a group improve foraging opportunities?

Answer 7

1. Finding food: Information centre hypothesis

2. Capturing food

Question 8

What are the costs of living in a group?

Answer 8

1. Resource competition
2. Maintenance of social status: dominant males spend a lot of time proving their dominance
3. Disease and parasite transmission
4. Reproductive interference: individuals want their young to survive more than the young of others

Question 9

Why would animals evolve for group living?

Answer 9

Cost-benefit analysis: do the benefits outweigh the costs?

Question 10

What are the types of helping behaviour?

Answer 10

• Mutualism: both donor and recipient get a benefit from it
• Reciprocity: both donor and recipient get a benefit but the donor is delayed
• Altruism: only the recipient gets something from it ( charity work)
• Selfish behaviour: only the donor gets something from it
• Spiteful behaviour: neither donor nor recipient gets something from it

Question 11

Is Group selection or Kin selection the currently accepted idea as to why animals help their colony?

Answer 11

Kin selection

Question 12

What is Kin selection?

Answer 12

Behaviour that lowers individuals own fitness but enhances the reproductive success of relatives (because the individual’s genes are still being passed on)

Question 13

What is the formula of Hamilton’s rule?

Answer 13

rB > C

r: coefficient of relatedness between donor and recipient
B: benefit to the recipient
C: cost in fitness to donor

Question 14

When should altruistic acts be favoured by selection?

Answer 14

When rB > C (Hamilton’s Rule)

Question 15

What is inclusive fitness?

Answer 15

The total number of genes passed on through one’s relatives (indirect fitness gain) + one’s own offspring (direct fitness gain).