Sexual selection

Question 1

Red Queen Hypothesis

Answer 1

An arms race to find a mate, reproduce and pass on your genes in constantly changing environment.

Question 2

Describe the relevance of parasites and hosts in sexual selection

Answer 2

Sex has evolved in response to a changing environment, namely parasites. Parasites/hosts in a continual arms race . Both are reactive to each other

Question 3

Explain Fisher’s Principle- sons

Answer 3

sexual populations should produce an equal number of males/females (1:1 ratio)- if this doesnt happen then more of one in the population puts pressure to breed the other (rarer sex at an advantage)

Question 4

Reproductive skew

Answer 4

males have a greater variance in reproductive succes than females

Question 5

Sexual asymmetry

Answer 5

differences between males and females of a species (stems from gametic differences)

Question 6

Fisher’s runaway selection

Answer 6

Features can ‘run’ away from their original function and become purely selected on the basis of their attractive features. I.e. natural selection leads males to produce greater ornamentation as females show greater preference for more ornamentation. However NS does keep this in check before overkill causes risk to male’s survival

Question 7

What’s Polygyny

Answer 7

one male with several female partners

Question 8

What’s the polygyny threshold model

Answer 8

Shows how females may gain a higher level of biological fitness by mating with a male who already has a mate. With it also comes increased environmental quality

Question 9

What’s Polyandry

Answer 9

one female with several males- effective polyandry leads to greater variance in female reproductive success (pretty non-existent in mammals/humans)

Question 10

What’s Polygynandry

Answer 10

both males and females have more than one sexual partner

Question 11

What is monogamy

Answer 11

one male and one female

serial monogamy- mate and separate

Question 12

Who benefits most from polygyny/ monogamy?

Answer 12

Men- polygyny

women- monogamy

Question 13

Explain Bateman’s rule?

Answer 13

in most species, variability in reproductive success (or reproductive variance) is greater in males than in females

Question 14

David Buss’ Texas Uni study (STM & LTM)

Answer 14

Study found ratings of mate qualities showed many similarities (i.e. mutual attraction, emotio

Question 15

Any key points from Buss’ (1982) study on Sexual conflict, jealousy in males/females?

Answer 15

More males found idea of infidelity distressing (60%)
More women found emotional infidelity (no sex) distressing (men 40%)
Males more likely to see mates as ‘property, i.e. mating guarding, sexual coercion and more chance of conflict

Question 16

What does the Red Queen hypothesis mean in the context of the evolution of sex

Answer 16

there is an evolutionary arms race between organisms and parasites, which creates a selection pressure for the evolution of sex as a source of variability