Chapter 7 Vocabulary

Question 1

Tells us what happens to a population if none of the evolutionary processes are at work

Answer 1

Hardy Weinberg Equilibrium

Question 2

What are the 3 HWE conclusions?

Answer 2

no evolutionary processes, no change in allele frequency
we can predict equilibrium genotype frequency
no evolutionary processes, then population will go into HWE in one generation

Question 3

What are the 5 HWE assumptions?

Answer 3

1. No Natural selection
2. no sexual selection
3. no mutation
4. no migration
5. no genetic drift

Question 4

What is the selection coefficient?

Answer 4

Genotype + fitness
s = 0 -> no selection against
s = 0.5 -> 505 reduction, hence selected against

Question 5

fitness associated with a trait is not directly dependent on the frequency of the trait in a population (e.x. rock Pocket mouse)

Answer 5

Frequency independent selection

Question 6

directional selection

Answer 6

dominant, incomplete, recessive

Question 7

overdominance or heterozygote advantage

Answer 7

balanced polymorphism

Question 8

under dominance or heterozygote disadvantage

Answer 8

unstable equilibrium, lost quickly as one allele goes to fixation quickly, heterozygotes selected against

Question 9

FOR: one extreme trait
AGAINST: the other extreme

Answer 9

Directional selection

Question 10

FOR: moderate traits
AGAINST: both extremes

Answer 10

Stabilizing selection

Question 11

FOR: both extremes
AGAINST: moderate traits

Answer 11

Disruptive selection

Question 12

overdominance or heterozygote advantage results in balanced polymorphism and is a case of stable equilibrium known as balanced selection

Answer 12

balanced polymorphism

Question 13

stable equilibrium, balanced selection

Answer 13

balanced polymorphism

Question 14

when the cost or benefit associated with the trait changes depending on its frequency in the population

Answer 14

frequency-dependent selection

Question 15

fitness of the trait increases as the frequency increases (snails only mate with the same direction of coil. more alleles=more potential partners=more mating)

Answer 15

Positive frequency dependent selection

Question 16

fitness associated with the trait decreases as frequency increases (drosophila maggots have sitters and rovers. increase sitters = increased competition = decreased fitness)

Answer 16

Negative frequency-dependent selection

Question 17

fitness is reproductive success relative to others, selection is not always living, sometimes just breeding provides all the advantage needed. Fecundity varies greatly and viability not at all

Answer 17

viability selection vs. fecundity selection

Question 18

when the rate of deleterious allele elimination = rate of new allele creation via mutation
- mutation alone is weak
-mutation + selection is very strong

Answer 18

Mutation and mutation-selection balance

Question 19

mate with those like you (IQ, appearance etc…)

Answer 19

assortative mating

Question 20

mate with those not like you (opposites attract). results in excess of heterozygotes

Answer 20

disassortative mating

Question 21

mating within the family (extreme assertive mating)

Answer 21

inbreeding

Question 22

alleles identical because they came from related individuals

Answer 22

identical by descent

Question 23

result of selfing and reproduction with genetic relatives. Happens as a consequence of increasing homozygosity

Answer 23

inbreeding depression

Question 24

what are the two important roles of migration?

Answer 24

1. it causes gene pools between populations to be more similar (decreases variation of the total population)
2. adds genetic variation to populations (increases variation of single population)