The Paradox Of Sex

Question 1

Why is sex bad

Answer 1

Finding mates is hard
Meiosis is slow and error prone
Advantageous genes on,unharnessed a 50/50 chance of transmission
Recombination breaks up advantageous gene combinations
Sexual organisms ‘waste’ half their reproductive effort on males

Question 2

Maynard smith model

Answer 2

2 false assumptions

1. Female reproductive mode doesn’t affect how many offspring she has
2. Female’s reproductive mode doesn’t affect the probability that her offspring will survive and reproduce

Question 3

2 long term advantages of sex

Answer 3

1. Reduces genetic load - accumulation of deleterious mutations in a pop. (Muller’s ratchet)
2. Promotes spread of beneficial mutations

Question 4

Muller’s ratchet

Answer 4

Without sex mutations accumulate and you can’t get rid of them, decreasing fitness over time

Question 5

Fisher-muller model

Answer 5

New beneficial mutations have higher probability of fixation if there is recombination than if there isn’t (don’t have to wait for separate mutations because of mating together)

Question 6

3 short term advantages of sex

Answer 6

1. Tangled bank model
2. Sib competition model
3. Red queen model

Question 7

Tangled bank model

Answer 7

If environment varies locally, diff genotypes might be optimal at diff sites

Question 8

Sin competition model

Answer 8

Genetically variable siblings might share resources better

Question 9

Red queen model

Answer 9

V well supported
Genetically variable progeny advantageous if: Negatively frequency dependant selection, temporally variable selection or Coevolution (circle)