Altruism & Kin Selection

Question 1

What is the unit that natural selection works on

Answer 1

An individual and their genes (not the group/ species)

Question 2

Define altruism

Answer 2

behaviour of an animal that benefits another at its own expense.

Question 3

How do Vervet monkeys show altruism

Answer 3

Sentinels warn other members when a hawk is overhead by making alarm calls
The call puts the monkey at risk of predation

Question 4

What is reciprocation

Answer 4

Reciprocity in evolutionary biology refers to mechanisms whereby the evolution of cooperative or altruistic behaviour may be favoured by the probability of future mutual interactions

Question 5

What species shows reciprocation in altruism

Answer 5

Vampire bats

Antelope (Allogrooming)

Question 6

How do vampire bats show reciprocation

Answer 6

Altruistic food sharing

• Must feed every couple of days
• Proportion of roost will be unsuccessful
• Blood is regurgitate from roost-mates

(Wilkinson, 1984) showed bats shared blood with kin and non-kin (preference was determined on relatedness)

Question 7

What are 2 reasons bats are more likely to food share

Answer 7

• if they were likely to encounter the individual in the future
• if they were related

Question 8

Why does the likelihood of a re-encounter increase likelihood of food sharing in bats?

Answer 8

Greater opportunity for reciprocation

Question 9

What 3 conditions are needed for reciprocation

Answer 9

• High number of repeated interactions
• Benefit outweighs cost of donating
• Donors must recognise recipients and not give to those that fail to reciprocate

Question 10

What did Wilkinson (1984) show about cost/ benefit to food-sharing in bats

Answer 10

Blood (i.e: food) donation causes weight loss equivalent to ~5hrs in the donor
BUT it provides the recipient with the equivalent of 20hrs

Shows the benefit exceeds the cost to donor

Question 11

What species shows allogrooming

Answer 11

Antelope

Question 12

Why are bats more likely to food share with relatives?

Answer 12

Kin selection

Question 13

What is kin selection

Answer 13

Kin selection is an evolutionary force which favours the evolution of traits (or persistence of genes) because of their net beneficial effect on the survival or reproduction of genetic relatives

Question 14

What does kin selection predict about altrusim

Answer 14

• Kin selection predicts that an individual will act altruistically to maximize the fitness of its relatives.