Chapter 23

Question 1

microevolution is defined at

Answer 1

a change in the allele frequency of a population from one generation to another

Question 2

_______________ is evolution at its most fundamental levels. Change within a population.

Answer 2

microevolution

Question 3

evolution operates on __________________

Answer 3

genetic variability

Question 4

the combination of darwinian evolution and mendelian genetics is referred to as the modern synthesis

Answer 4

genetic variability

Question 5

two processes produce the genetic variation on which evolution acts

Answer 5

• mutations

- sexual reproduction

Question 6

changes in the nucleotide sequences of DNA

Answer 6

Mutations

Question 7

Mutation can

Answer 7

be harmful or have no effect

Question 8

mutation may occasionally confer an advantage and be selected for

Answer 8

mutations are responsible for producing new allies, new genes, and ultimately all of the diversity of life.

Question 9

____________________ rearranges existing alleles into new combinations by way of three mechanisms

Answer 9

sexual reproduction

1. crossing over
2. independent assortment of chromosomes
3. random fertilization

Question 10

___________________ is a larger contributor to genetic variability than are mutations in sexual organisms

Answer 10

reproduction

Question 11

allele are ____________________________ within a population

Answer 11

alternative forms of genes

Question 12

_______________ consists of all of the alleles for all of the genes within all of the individuals in the population

Answer 12

populations gene pool

Question 13

the portion of a population that is dominate is represented by

Answer 13

P

Question 14

the portion of a population that is recessive is represented by

Answer 14

q

Question 15

equation of p and q

Answer 15

p + q=1

Question 16

knowing allele frequency allows us to determine

Answer 16

genotype frequency

Question 17

proportion of homozygous dominant

Answer 17

p^2

Question 18

proportion of heterozygous

Answer 18

2pq

Question 19

the proportion of homozygous recessive

Answer 19

q^2

Question 20

the hardy-weignberg equation

Answer 20

p^2+2pq+q^2

Question 21

if the allele and genotype frequencies remain the same from one generation to the next the population is in Hardy-Weinberg equilibrium

Answer 21

it is not evolving

Question 22

if allele and genotype frequencies do change from generation to another, the population is undergoing

Answer 22

microevolution

Question 23

there mechanisms cause allele frequencies and therefore genotype frequencies to change with in the population

Answer 23

genetic drift
gene flow
natural selection

Question 24

____________ is the change in the allele frequencies of small populations due to ______________

Answer 24

genetic drift

Question 25

_____________ can increase or decrease the proportion of helpful or harmful alleles. tends to reduce genetic variability within a population over time

Answer 25

genetic drift

Question 26

two examples of genetic drift

Answer 26

- bottleneck effect | - founder effect

Question 27

_______________ occurs when a few individuals become isolated from a larger population thereby colonizing a new smaller population

Answer 27

the founder effect

Question 28

_____________________ occurs when a population's size is significantly reduced often by natural disaster

Answer 28

bottleneck effect

Question 29

in both cases, allele frequencies in the new smaller population may by chance ____________________________________________

Answer 29

be different from allele frequencies in the original larger population

Question 30

________________ is the transfer of alleles between populations

Answer 30

gene flow

Question 31

allele are transferred due to the movement of _______________

Answer 31

individuals and their gametes

Question 32

gene flow can increase or decrease the proportion of

Answer 32

helpful or harmful alleles

Question 33

gene flow tends to reduce genetic variability

Answer 33

between populations over time | -the gene pools of the populations become more similar

Question 34

____________ is unequal reproduction

Answer 34

natural selection

Question 35

natural selection is only ___________________ that consistently promotes __________________________

Answer 35

microevolutionary mechanism | adaptive evolution

Question 36

populations become better _____________ to their environments over time as advantageous alleles are passed among generations to greater proportions

Answer 36

adapted

Question 37

___________ increase the frequency whole harmful allele decrease during ______

Answer 37

helpful allele | natural selection

Question 38

for population to be in Hardy Weinberg equilibrium (allele and genotype frequencies remain constant from one generation to the next; the population is not evolving) the population must be

Answer 38

- the population must be very large | - genetic drift as a result would have no effect

Question 39

more qualifications for Hardy Weinberg equilibrium

Answer 39

- there must be no movement of individuals or their gametes into immigration or out of emigration a population - natural selection must not occur - there must be no mutations - mating must have no mutations: individuals within a population cannot preferentially choose mates this would affect the random fertilization

Question 40

how common is Hardy Weinberg equilibrium

Answer 40

not very alleal frequencies are changing, microevolution is constantly occurring, populations are constantly evolving

Question 41

two type of balancing selection

Answer 41

- frequency dependent selection | - heterozygote selection

Question 42

__ is being defined as an individuals contribution on the next generations gene pool

Answer 42

fitness

Question 43

the number of offspring an individual produces relative to the number of offspring produce by all other individuals in the population

Answer 43

fitness

Question 44

natural selection results in competitively superior individuals surviving and reproducing

Answer 44

these individuals have the greatest fitness

Question 45

________________________ changes the frequencies of allele and genotypes in a population based on which phenotypes are favored

Answer 45

natural selection

Question 46

one extreme of a phenotype is selected for | ex- dark rat

Answer 46

directional selection

Question 47

both extremes of a phenotype range are selected for | ex- dark and white rat

Answer 47

disruptive selection

Question 48

intermediate phenotype is selected for | ex- brown rat

Answer 48

stabilizing selection

Question 49

_____________________ occurs when natural selection maintains two or more phenotypes within a population and helps to preserve the populations genetic diversity

Answer 49

balancing selection

Question 50

__________________________ the fitness of a phenotype depends on how common it is in the population

Answer 50

frequency dependent selection

Question 51

frequency dependent selection: | the fitness of a phenotype ________________ if the phenotype becomes too common. Selections favor less common

Answer 51

decline

Question 52

_______________ occurs when individuals heterozygous for a particular gene have higher fitness than individuals homozygous dominant or homozygous recessive for that gene

Answer 52

heterozygous advantage

Question 53

heterozygous advantage maintains

Answer 53

both alleles for the gene within a given population

Question 54

In certain regions of africa _______________________ suffer from sickle cell disease

Answer 54

4% of the population suffers from sickle sell disease | q^2=0.04

Question 55

sick cell is a __________________

Answer 55

a homozygous recessive disorder

Question 56

why is the frequency of sickle cell high wouldn't the individual die before they can reproduce

Answer 56

sick cell has an advantage. resistance to malaria which is supper prevalent in some regions of malaria

Question 57

____________________ individuals are protected against malaria but have sickle cell ____________ individuals are not protected against malaria but do not have malaria ____________________ individuals are protected against malaria and do not have sick cell

Answer 57

homozygous recessive homozygous dominant heterozygous example of heterozygous example

Question 58

q^2=0.04 q=0.2 p=0.8 2pq=0.32

Answer 58

the sick cell allel is helpful to 32% to population but only harmful to 4% of the population so it permits

Question 59

sexual selection is a form of

Answer 59

natural selection

Question 60

______________ if the limited resource for which individuals compete for is

Answer 60

mates

Question 61

the "environment" selects for advantageous traits is

Answer 61

opposite sex

Question 62

sexual selection frequently results in

Answer 62

sexual dimorphism

Question 63

differences in size color ornamentation and behavior of the two sexes

Answer 63

sexual dimorphism

Question 64

natural selection can only select for __________________ which may not be the most advantageous traits

Answer 64

existing variations

Question 65

natural selection is contracted by

Answer 65

descent with modification

Question 66

adaptions are often ___________

Answer 66

compromises or trade offs

Question 67

natural selection has to interact with other mechanisms of evolution as well as with a potentially

Answer 67

changing environment