LO16

Question 1

Definition: the study of the genetic variability in a population and the evolutionary forces that affect it

Answer 1

population genetics

Question 2

each population has what?

Answer 2

gene pool

Question 3

definition: all of the alleles from all of the loci present in a population

Answer 3

gene pool

Question 4

how is population genetics studied?

Answer 4

By tracking genotype, phenotype, and or allele frequency changes across generations

Question 5

definition: how often a particular genotype or phenotype or allele occurs divided by the total number of occurances

Answer 5

frequency

Question 6

frequency is always between which numbers

Answer 6

0 and 1

Question 7

is gene pool applied to individuals or populations

Answer 7

populations

Question 8

equation for allele, phenotype ofr genotype frequency

Answer 8

of certain allele/ total # of occurances

Question 9

definition: the proportion of a particular genotype in a population

Answer 9

genotype frequency

Question 10

definition: proportion of a particular phenotype in a population

Answer 10

phenotype frequency

Question 11

definition: the proportion of a particular allele from a given locus in a population

Answer 11

allele frequency

Question 12

what is occuring in the allele and/or genotype frequencies change over time

Answer 12

evolution

Question 13

allele and genotype frequencies do not change from generation to generation unless what?

Answer 13

they are affected by outside forces

Question 14

if a population is large how does sexual reproduction change allele and genotype frequencies?

Answer 14

it doesn’t change

Question 15

definition: when allele and genotype frequencies are stable for a trait the population is not evolving at the locus

Answer 15

genetic equilibrium

Question 16

What does the Hardy-Weinberg equation demonstrate?

Answer 16

How populations remain at genetic equilibrium

Question 17

H-W equation used to calculate what?

Answer 17

expected genotype frequencies

Question 18

Allele frequency equation

Answer 18

p+q=1

Question 19

p is what?

Answer 19

frequency of the dominant allele

Question 20

q is what?

Answer 20

frequency of recessive allele

Question 21

H-W genotype frequency equation

Answer 21

p^2 + 2pq + q^2 = 1

Question 22

p^2 is what?

Answer 22

frequency of homozygous dominant genotype

Question 23

2pq is what?

Answer 23

frequency of heterozygous genotype

Question 24

q^2 is what?

Answer 24

frequency of homozygous recessive genotype

Question 25

What happens if the genotype frequencies for a locus conform to H-W equation?

Answer 25

It means that the population is at genetic equilibrium and not evolving

Question 26

The H-W equation is used to calculate what type of genotype frequencies?

Answer 26

expected

Question 27

What are the 5 H-W Assumption

Answer 27

1. Mating is random 2. there are not mutations 3. The population is large (no genetic drift) 4. individuals do not migrate between populations (no genetic flow) 5. natural selection does not occur

Question 28

H-W only applies to what kind of populations?

Answer 28

sexually reproducing

Question 29

What kind of model does H-W provide?

Answer 29

A useful null model

Question 30

Do natural populations fit H-W?

Answer 30

only rarely

Question 31

What does the difference between the H-W equilibrium and the observed variables mean?

Answer 31

how much evolutionary change is occuring in the population

Question 32

In the H-W mates must be selected how?

Answer 32

randomly

Question 33

In H-W nucleotides may or may not change due to mutations?

Answer 33

may not

Question 34

When can genotype frequencies be determined from phenotype frequencies?

Answer 34

if they are assumed to be in H-W equilibrium

Question 35

definition: generates genetic diversity by creating new alleles

Answer 35

mutation

Question 36

The microevolutionary forces are what?

Answer 36

mutation, genetic drift, genetic flow, natural selection

Question 37

What will eliminate or reduce harmful mutations?

Answer 37

natural selection

Question 38

definition: mutations with minor effects

Answer 38

neutral mutations

Question 39

What happens to neutral mutations?

Answer 39

they may persist in a population and be adaptive later as the environment changes

Question 40

What would happen if a bacterium acquires a mutation that causes it to be unaffected by a particular chemical?

Answer 40

the mutations would become beneficial when the chemical is used later

Question 41

What changed allele frequencies by creating new alleles in a populations?

Answer 41

mutations

Question 42

mutations are essential to produce what?

Answer 42

genetic variation

Question 43

do mutations significantly change frequencies?

Answer 43

do not

Question 44

definition: occurs when random events cause allele frequency changes especially in smaller populations

Answer 44

genetic drift

Question 45

What does genetic drift do to genetic variation

Answer 45

decreases it

Question 46

what does genetic drift do to genetic differences between populations?

Answer 46

increases genetic differences

Question 47

is genetic drift adaptive?

Answer 47

no it isnt

Question 48

definition: genetic drift a sudden decrease in a population size caused by environmental factors

Answer 48

bottlenecks

Question 49

What happens to the surviving population of a bottleneck genetic drift?

Answer 49

They have different allele frequencies compared to the original population

Question 50

definition: genetic drift an event that occurs when a few individuals from a large population colonize a new area

Answer 50

founder event

Question 51

What happens to the founding population's allele frequencies in a founder event?

Answer 51

They have different allele frequencies

Question 52

definition: when allele frequencies change because alleles are carried from one population to another by the migration of breeding individuals

Answer 52

gene flow

Question 53

what does gene flow do to genetic variability of the population?

Answer 53

it increases genetic variability

Question 54

What does gene flow do to genetic differences?

Answer 54

it decreases genetic differences in a population

Question 55

If gene flow is extensive what could happen?

Answer 55

the population could become genetically similar

Question 56

Is gene flow adaptive?

Answer 56

not necessarily

Question 57

definition: changes allele frequencies by selecting the phenotypes that are more fit in current environment

Answer 57

natural selection

Question 58

What happens to less fit phenotypes in natural selection?

Answer 58

they are reduced or eliminated

Question 59

definition: the relative ability of a genotype to make a genetic contribution to future generations

Answer 59

fitness

Question 60

Is natural selection adaptive?

Answer 60

yes that is how the alleles are chosen

Question 61

natural selection can only choose from what in a population?

Answer 61

genetic variants; alleles that already existq

Question 62

what are the types of natural selection?

Answer 62

stabilizing, directional, heterozygote advantage

Question 63

definition: type of natural selection that selects against phenotypic extremes

Answer 63

stabilizing selection

Question 64

What does stabilizing selection do to genetic variation?

Answer 64

decreases it

Question 65

What individuals does stabilizing selection favor?

Answer 65

those with average phenotypes

Question 66

definition: type of natural selection that selects for phenotypes at one extreme

Answer 66

directional selection

Question 67

What affects directional selection?

Answer 67

environmental changes

Question 68

definition: maintains alleles in a population that are unfavorable in the homozygous state

Answer 68

heterozygote advantage

Question 69

which genotype has the lower fitness in heterozygote advantage?

Answer 69

homozygote

Question 70

What does heterozygote advantage do to genetic diversity?

Answer 70

maintain it.