Social Evolution

Question 1

What is “social evolution”?

Answer 1

Interactions between individuals

Question 2

Benefits of group living: food (5)

Answer 2

1. More eyes to locate
2. Less time wasted searching
3. Share information
4. Co-operation in hunting
5. Co-operation in defending food

Question 3

Benefits of group living: predation avoidance (5)

Answer 3

1. Selfish herd effect - get to the middle of the herd
2. Dilution effect - less likely to be taken by a single predator
3. Vigilance effect - can have members on ‘look out’
4. Confusion effect - lots of members scattering can be confusing
5. Co-operative defence

Question 4

Benefits of group living: social benefits (5)

Answer 4

1. Learning is easier
2. Finding a mate is easier
3. Sharing information is easier
4. Asssistance in rearing offspring
5. Divisions of labour

Question 5

Costs of group living (4)

Answer 5

1. Competition for food and mates
2. Spread of disease
3. Increased conspicuousness to both prey and predators
4. Increased cuckoldry

Question 6

What is the Socioecological Model?

Answer 6

Females arrange themselves in respect to food

Males arrange themselves in respect to females

Question 7

What are the 4 diet types?

Answer 7

1. Frugivory - fruit
2. Folivory - leaves
3. Faunivory - animals
4. Gumnivory - gums secreted by injured trees

Question 8

What are the 2 types of resource distribution?

Answer 8

1. Even distrbution - scramble -> everyone goes around and collects what they can, but it cannot be defended
2. Patch distribution - contest -> access can be defended and controlled

Question 9

Define “dominance”

Answer 9

The ability to defeat another in a one on one encounter

Question 10

What are the 5 social systems?

Answer 10

1. Solitary
2. Monogamous
3. Polyandry (one female, multi-male)
4. Polygny (one male, multi-female)
5. Polygamy (multi-male, multi-female)

Question 11

What are the features of solitary living?

Answer 11

Low sexual dimorphism

Often males with no secondary sexual traits that impregante unsuspecting females e.g. ducks

Question 12

What are the features of monogamous living?

Answer 12

Competition with other males is low
No sexual dimorphism
Both females and males guard the territory

Question 13

What are the features of polyandry?

Answer 13

Only seen when offspring need a lot of investment e.g. when infants need carrying

Question 14

What are the features of polygny?

Answer 14

Females are tightly clustered together
Very high competition between males
Very high sexual dimorphism

Question 15

What are the features of polygamy?

Answer 15

Often competition between females

Females don’t become oestrous at the same time so there is male/male competition

Question 16

Define “altruism”

Answer 16

Helping another individual at the cost of your own fitness

Question 17

How do you calculate inclusive fitness?

Answer 17

Direct fitness + indirect fitness

Question 18

How do you calculate whether altruism will occur?

Answer 18

rb>c
b = benefit to recipient
r = coefficient of relatedness
c = cost to the altruist

Question 19

When will reciprocal altruism occur?

Answer 19

When the cost of altruism is low
When the benefit to the recipient is high
When there are expected repeated interactions
When the ‘penalty’ for cheating is the loss of future benefits