19 - Evolutionary Conflict and Cooperation

Question 1

Name 3 family conflicts

Answer 1

• mate conflict
• parent-offspring
• sibling conflict

Question 2

Why do family conflicts happen?

Answer 2

• differences in investment of gametes in male and female parents
• investment needed in offspring success

Question 3

When does a male benefit from females?

Answer 3

• they invest in his offspring
• they invest in current reproduction

Question 4

When does a female benefit from males?

Answer 4

• produce offspring with best quality of male
• get the greatest investment or least harm from males

Question 5

What is the effect of investing in offspring on male mating opportunities?

Answer 5

• reduces mating opportunities for males more then females

Question 6

Explain parent-offspring conflict

Answer 6

• offspring want as much resources from parents
• parents want to invest the least amount possible

Question 7

What are genomic conflicts within an organism?

Answer 7

• paternal DNA -> wanting to get as much resources as possible
• maternal DNA -> DNA is shared with siblings. May want to limit resources extracted

Question 8

Explain Igf2 in rats

Answer 8

• Igf2 activated in paternal DNA, deactivated in maternal DNA
• if Igf2 receptor activated, inhibits Igf2, turned of in males and on in females

Question 9

What is interlock sexual conflict?

Answer 9

• male and female traits that interact are controlled by different loci

Question 10

What is chase away sexual selection?

Answer 10

• inter-loci sexual conflict
• males evolve methods to damage females
• females fight back

Question 11

What can selective advantage for male genes cause females to do?

Answer 11

• use his sperm instead of competitors
• immediately after mating produce more eggs or better eggs
• reduce mating (decrease attractiveness or receptivity)

Question 12

What is intra-locus sexual selection?

Answer 12

Male and female traits have different optima controlled by the same locus

Question 13

What is intra-locus sexual antagonism?

Answer 13

• poor males make fit daughters
• fit males make poor daughters
• average make average

Question 14

Explain intra-locus sexual antagonism in terms of selection coefficients

Answer 14

perfect male = 1
perfect female = 2

• female that inherits both male loci will be 1 - t
• male than inherits both female loci will be 1 - s
• if they are heterozygous it will be 1 - h(f or m) x (s or t)
  h = dominance

Question 15

What is required for intra-locus sexual selection?

Answer 15

s and t > 0

Question 16

Explain sex chromosome linkage if the loci is at the pseudoautosomal region

Answer 16

• if at loci in pseudoautosomal region then crossing over between X and Y can happen
• will inherit one chromosome form mum, other could be either the allele on X or Y by crossing over

Question 17

Explain sex chromosome linkage if the loci is not at the pseudoautosomal region

Answer 17

• one chromosome from mum, dad can only offer up the two chromosomes with no crossing over

Question 18

How does sex chromosome linkage lead to shrinkage of the Y chromosome?

Answer 18

• there is a selective advantage to removing alleles from the pseudoautosomal region

Question 19

What are 4 possible explanations for altruism?

Answer 19

• collective self interest - benefits individuals
• mutual benefit - can be repair later (reciprocal altruism)
• group selection
• kin selection

Question 20

What is group selection and the cons?

Answer 20

• doing thins for the good of the group
• unit of selection on the group

Cons
- as you reach carrying capacity, reproduction slows and stops
- dominant females evict pregnant subordinate females
- not evolutionary stable

Question 21

What is an evolutionary stable strategy?

Answer 21

• strategy that when adopted by the population, cannot be invaded by any alternative strategy

Question 22

What is r?

Answer 22

• coefficient of relatedness
• the probability that an allele present in a n individual is also present by common decent in its relatives

Question 23

What does a large and small r mean?

Answer 23

large = closer related
small = less related

Question 24

what relation is r = 1?

Answer 24

yourself

Question 25

What relation is r = 0.5

Answer 25

• full siblings
• parents / offspring

Question 26

What relations are r = 0.25?

Answer 26

• half siblings
• aunt or uncle / niece or nephew
• grandparent / grandchild

Question 27

What relation is an r = 0.125?

Answer 27

first cousins

Question 28

what is inclusive fitness and what is the equation?

Answer 28

• measure of evolutionary success through relatives

wi = ai - ci + sigma(rijbij)

wi = inclusive fitness of donor
ai = direct fitness of donor
ci = effect of altruistic act on donors own direct fitness
rij = coefficient of relatedness between donor and recipient
b = increate in fitness of recipient due to action of donor

Question 29

What is Hamilton’s rule?

Answer 29

• altruism will evolve if:

relatedness * benefit > cost to donor
E*b - c > 0

• if relatedness if small then benefits have to be large or costs small
• if relatedness is large then there wont need to be as much benefit and can be a larger cost