Hardy Weinberg and Gene Pool Changes

Question 1

what are some of the processes that can cause microevolution (5)

Answer 1

1. inheritable mutations that may be beneficial, neutral or detrimental in a given environment
2. gene flow due to the emigration and immigration of individuals
3. non-random mating
4. genetic drift that can result in the loss of alleles
5. natural selection for favorable phenotypes

Question 2

what is a disadvantage of gene flow

Answer 2

it reduces genetic differences among populations

Question 3

true or false: hardy-Weinberg conditions are often met

Answer 3

false; the principle represents an ideal situation that rarely occurs in natural populations

Question 4

what is the benefit of gene flow

Answer 4

it indtorduces new alleles into the gene pool of the nearby population which increases the genetic diversity in that population adn may help it to survive

Question 5

what are founders

Answer 5

a few individuals that form a new population

Question 6

why is the hardy-Weinberg principle considered valuable

Answer 6

it can be used to measure the amount of change in the allele frequencies of a population over time

Question 7

define founder effect

Answer 7

the gene pool change that occurs when a few individuals start a new isolated population

Question 8

define population

Answer 8

a group of organisms of the same species that live together in a defined area and time

Question 9

define bottleneck effect

Answer 9

gene pool change that results from a rapid decrease in population size

Question 10

define heterozygote advantage

Answer 10

a survival benefit for those individuals who inherit two different alleles for the same trait compared to those who are homozygous dominant or homozygous recessive

Question 11

what does inbreeding increase

Answer 11

frequency of homozygous genotypes since close relatives share similar genotypes

Question 12

define random mating

Answer 12

when there is no way to predict which males will mate with which females and vise versa

Question 13

what is the result to a populations gene pool after the bottleneck effect

Answer 13

the gene pool will lose diversity since they only have a subset of the alleles that were present before the decline

Question 14

define genetic diversity

Answer 14

the degree of variation within a species or population

Question 15

what is a back mutation

Answer 15

mutation that reverses the effects of a former mutation

Question 16

what does 2pq represent

Answer 16

frequency of heteroxygous genotype

Question 17

define genetic equiolibrium

Answer 17

when there is no change in allele frequencies over time so the population is not changing or evolbing

Question 18

whats the relationship between the number of alleles and number of individuals in a population

Answer 18

the number of alleles in a population is twice the number of individuals since each organisms have two possible alleles for every gene

Question 19

in hardy weinberg how are the genotypes in the gene pool represented

Answer 19

by p^2, 2pq, and q^2

Question 20

what are the 5 conditions for the hardy Weinberg principle

Answer 20

1. the population must be large enough that chance events will not alter allele frequencies
2. mates are chosen on a random basis
3. there are no mutations
4. there is no migration
5. there is no natural selection against any of the phenotypes

Question 21

define genotype frequency

Answer 21

proportion of a population with a particular genotype

Question 22

whats inbreeding

Answer 22

when closely related individuals breed together

Question 23

what is the gene pool like among founders

Answer 23

it will be limited because they only carry some of the alleles in the original population so there will not be much diversity

Question 24

why is random mating uncommon in natural populations

Answer 24

because of preferred phenotypes and inbreedfing

Question 25

how can the number of individuals with a particular genotype be calculated if the population size is known

Answer 25

by using p^2(N) + 2pq(N) + q^2(N) = N

Question 26

what does p^2 represent

Answer 26

frequency of the homozygous dominant genotype

Question 27

when does the bottneck effect occur

Answer 27

when there are events that quickly reduce a large population

Question 28

define mutation

Answer 28

a change that occurs in teh DNA of an individual

Question 29

how do you calculate the frequency of each allele

Answer 29

you divide the incidence of the allele by the total number of alleles in the sample

Question 30

what does q^2 represent

Answer 30

frequency of homozygous recessibe genotype

Question 31

what does genetic drift cause in small populations

Answer 31

causes them to be more likely to completely lose alleles from its gene pool

Question 32

define natural selection

Answer 32

process where the characteristics of a population change over time because the individuals with certain heritable traits survive specific local environmental conditions and through reproduction pass on their traits to their offspring

Question 33

what does the total of allele frequencies for one gene locus alwaus equal

Answer 33

1 or 100%

Question 34

is genetic drigt experienced by large populations

Answer 34

generally not becuase chance events are unlikely to affect overall allele frequencies

Question 35

define genes

Answer 35

carried on chromosomes and control the inheritance of traits

Question 36

define gene flow

Answer 36

the movement of alleles from one population to another due to the migration of individuals

Question 37

how are the frequences of dominant and recessive alleles represented

Answer 37

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

Question 38

define allele frequency

Answer 38

the rate of occurrence of a particular allele in a population with respect to a particular gene

Question 39

define microevolution

Answer 39

the gradual change in allele frequencies in a population

Question 40

why are harmful recessive alleles more likely to be expressed with inbreeding

Answer 40

because homozygous genotypes become more common as inbreeding continues

Question 41

what are some main processes that cause changes in gene pools (5)

Answer 41

genetic mutations, gene flow, non-random mating, genetic drift, natural selection

Question 42

define allele

Answer 42

the different forms of a gene

Question 43

define gene pool

Answer 43

sum of all the alleles for all the genes in a population

Question 44

define genetic drift

Answer 44

a change in allele frequencies due to chance events in a small breeding population

Question 45

when does natural selection occur

Answer 45

when a mutation produces a phenotype that gives on individual a sruvival adnatage over anotehr

Question 46

what does p represent

Answer 46

dominant alleles

Question 47

what does q represent

Answer 47

recessive alleles

Question 48

whats the hardy weinberg principle

Answer 48

a principle that shows that allele frequencies in a population will remain the same from one generation to the next as long as 5 conditions are met

Question 49

define non-random mating

Answer 49

mating based on mate selection due to phenotype selection or because of inbreeding

Question 50

what is the only process that directly leads to evolutionary adaptation

Answer 50

natural selection

Question 51

define phenotype frequency

Answer 51

the proportion of a population with a particular phenotype

Question 52

what does an inheritable mutation have the potential to do

Answer 52

affect an entire gene pool

Question 53

how does genotype frequency affect survival rates of a population

Answer 53

the more variety in the gene pool of a population, the better chance the population has in surviving within a changing environment