Lecture 19 - Evolutionary Conflict and Cooperation

Question 1

What are the main types of family conflicts?

Answer 1

Sibling conflicts
Mate conflicts
Parent-offspring conflicts

Question 2

Why do family conflicts arise?

Answer 2

Differences in investment in gametes of males and females.
Differences in parental investment required for offspring success.

Sibling conflict over resources (r = 0.5).
Parent-offspring conflict over resource allocation (r = 1 for offspring, but 0.5 for parents).

Question 3

What is sexual conflict?

Answer 3

Males aim to increase offspring quantity by seeking multiple mates.
Females aim to increase offspring quality by being selective in mate choice.

Question 4

How does parental care lead to conflict?

Answer 4

Investment in current offspring can reduce mating opportunities for males.
Females generally benefit more from providing care to maximise offspring survival.

Question 5

What is parent-offspring conflict?

Answer 5

Offspring seek to maximise parental investment for their benefit.
Parents aim to allocate resources to maximise future reproductive opportunities.

Question 6

How do conflicts occur during pregnancy in mammals?

Answer 6

Genetic conflict between maternal and paternal genes controlling offspring growth.

Example: Insulin-like growth factor (IGF2) in rats, regulated differently by maternal and paternal genes.

Question 7

What is evolutionary sexual conflict?

Answer 7

Conflict over traits benefiting one sex but harming the other.

Examples include inter-loci sexual conflict (arms race) and intra-loci sexual conflict (tug of war over optimal traits).

Question 8

What is an example of inter-loci sexual conflict?

Answer 8

Male seed beetles damaging female reproductive tracts to prevent re-mating.
This leads to evolutionary arms races between the sexes.

Question 9

What is intra-loci sexual conflict?

Answer 9

When male and female traits share the same genetic loci but have different optima.
Example: Males benefit from bright colours for mating, while females prefer camouflage for survival.

Question 10

What is Hamilton’s Rule?

Answer 10

Altruism evolves if r×b>c, where
r is relatedness,
b is the benefit to the recipient, and c is the cost to the donor.

Question 11

What are the possible explanations for altruism?

Answer 11

Collective self-interest (e.g., cooperative hunting).
Mutual benefit (e.g., reciprocal altruism).
Kin selection (e.g., helping close relatives reproduce).

Question 12

What is the concept of inclusive fitness?

Answer 12

Combines direct fitness (personal reproduction) and indirect fitness (helping relatives reproduce).

Question 13

How does sibling conflict arise?

Answer 13

Siblings share only 50% of genes (r = 0.5), leading to competition for parental resources.

Question 14

What are the consequences of sex chromosome linkage in intra-loci conflict?

Answer 14

Can lead to selective pressure removing harmful alleles from one sex over another, causing potential chromosome shrinkage.

Question 15

What are the main explanations for cooperation?

Answer 15

Collective self-interest (e.g., group hunting).

Mutual benefit (e.g., reciprocal altruism).

Kin selection (e.g., inclusive fitness).

Question 16

What is sex chromosome linkage in intra-loci conflict?

Answer 16

Sex chromosome linkage occurs when sexually antagonistic genes are located on the sex chromosomes, influencing the evolution of traits like colouration or courtship behaviours.

Question 17

How can sexual conflict lead to speciation?

Answer 17

If populations are geographically isolated and experience differing sexual conflicts, they may diverge in traits and evolve separately, leading to speciation.

Question 18

How does sexual antagonism affect fitness?

Answer 18

Sexual antagonism occurs when the same gene has contrasting effects on male and female fitness, often resulting in suboptimal traits for one sex (e.g., bright coloration in guppies).

Question 19

Why is group selection not an Evolutionarily Stable Strategy (ESS)?

Answer 19

Group selection fails as an ESS because selfish individuals that act against the group’s interests can invade and outcompete altruistic individuals.

Question 20

What is inclusive fitness?

Answer 20

Inclusive fitness is the sum of:

Direct fitness: Offspring an individual produces.
Indirect fitness: The impact on relatives’ reproductive success, weighted by relatedness.

Question 21

What are the differences between inter-loci and intra-loci sexual conflict?

Answer 21

Inter-loci sexual conflict: Traits are controlled by different loci in males and females, often leading to arms races.

Intra-loci sexual conflict: Traits are controlled by the same loci but have different fitness optima in males and females, leading to a “tug-of-war”.

Question 22

What is the “Red Queen Hypothesis” in evolutionary conflict?

Answer 22

The Red Queen Hypothesis suggests that species must continuously adapt to survive due to ongoing evolutionary arms races between predators and prey or hosts and parasites.