Chapter 23

Question 1

Natural selection acts on the

Answer 1

individuals

Question 2

The effects of natural selection

Answer 2

evolution

Question 3

effects (evolution) of natural selection are seen at the

Answer 3

population level

Question 4

Genetic variation

Answer 4

differences among individuals in the composition of their genes or other DNA sequences

Question 5

differences among individuals in the composition of their genes or other DNA sequences

Answer 5

Genetic variation

Question 6

Genetic code (genotype)

Answer 6

determines the physical expression of a trait (phenotype)

Question 7

determines the physical expression of a trait (phenotype)

Answer 7

Genetic code (genotype)

Question 8

What plays a role in phenotypic expression?

Answer 8

Environment

Question 9

What is a product of genotype and environmental factors

Answer 9

Phenotype

Question 10

What is phenotype the product of?

Answer 10

The product of genotype and environmental factors

Question 11

Sources of genetic variation

Answer 11

1. Formation of new alleles
2. Altering gene number or position
3. Rapid reproduction
4. Sexual reproduction

Question 12

Mutations

Answer 12

change the nucleotide sequence

Question 13

change in the nucleotide sequence

Answer 13

mutations

Question 14

Mutations that result in new phenotypes tend to be…

Answer 14

maladaptive and are removed by natural selection

Question 15

What are harmful recessive traits masked by?

Answer 15

heterozygote protections

Question 16

Where do neutral mutations occur?

Answer 16

in non-coding regions (neutral variation)

Question 17

Redundancy of genetic code

Answer 17

a source of neutral variation

Question 18

a source of neutral variation

Answer 18

redundancy of the genetic code

Question 19

Population

Answer 19

a group of organisms of the same species occurring in the same place at a given time

Question 20

a group of organisms of the same species occurring in the same place at a given time

Answer 20

population

Question 21

Microevolution

Answer 21

change in allele frequencies in a population over generations

Question 22

change in allele frequencies in a population over generations

Answer 22

Microevolution

Question 23

Where does microevolution occur?

Answer 23

The population level

Question 24

What causes adaptive evolution

Answer 24

natural selection

Question 25

genotype

Answer 25

the genetic make up, or set of alleles, of an organism

Question 26

the genetic make up, or set of alleles, of an organism

Answer 26

genotype

Question 27

phenotype

Answer 27

the observable physical or physiological traits of an organism (determined by genotype)

Question 28

the observable physical or physiological traits of an organism (determined by genotype)

Answer 28

phenotype

Question 29

Gregor Mendel

Answer 29

Austrian monk that determined there are "units" of inheritance (now called genes)

Question 30

Austrian monk that determined there are "units" of inheritance (now called genes)

Answer 30

Gregor Mendel

Question 31

Sexual reproduction

Answer 31

shuffles existing alleles into new combinations

Question 32

Types of sexual reproduction

Answer 32

1. Independent Assortment 2. Crossing over 3. Fertilization

Question 33

Independent assortment

Answer 33

homologous chromosomes pair up randomly during meiosis (cellular division)

Question 34

homologous chromosomes pair up randomly during meiosis (cellular division)

Answer 34

Independent assortment

Question 35

Crossing over

Answer 35

genetic material is swapped (exchanged) during meiosis

Question 36

genetic material is swapped (exchanged) during meiosis

Answer 36

crossing over

Question 37

Fertilization

Answer 37

a number of mating opportunities exist within a population, resulting in joining of gametes with genetic background

Question 38

a number of mating opportunities exist within a population, resulting in joining of gametes with genetic background

Answer 38

fertilization

Question 39

a population's genetic make up is characterized by describing its...

Answer 39

gene pool

Question 40

Gene pool

Answer 40

all copies of every type of allele at every locus in all members of the population

Question 41

all copies of every type of allele at every locus in all members of the population

Answer 41

gene pool

Question 42

Fixed allele

Answer 42

occurs if only one allele exists for a particular locus (all individuals are homozygous for the allele)

Question 43

occurs if only one allele exists for a particular locus (all individuals are homozygous for the allele)

Answer 43

fixed allele

Question 44

Tthe proportion of each allele in the gene pool?

Answer 44

allele frequency

Question 45

Allele frequency

Answer 45

the proportion of each allele in the gene pool

Question 46

Allele frequency remains constant from...

Answer 46

Generation to generation (no evolution)

Question 47

Conditions for Hardy-Weinberg Equilibrium

Answer 47

1. No mutations 2. Random mating 3. No natural selection 4. Extremely large population size 5. No gene flow

Question 48

Mechanisms of evolution

Answer 48

1. mutation 2. non-random mating 3. genetic drift 4. gene flow 5. natural selection

Question 49

Mutation (2)

Answer 49

a source of variation

Question 50

Random with respect to fitness

Answer 50

Mutation

Question 51

harmful mutations are...

Answer 51

phased out, beneficial alleles increase

Question 52

Since mutations rarely occur...

Answer 52

there is very little change in allele frequencies from generation to generation

Question 53

Non-random mating

Answer 53

occurs when individuals mate within a subset of the population

Question 54

Non-random mating my affect the frequencies of heterozygotes and homozygotes, but...

Answer 54

unless individuals with certain ingerited traits are more likely to obtain mates, allele frequencies are unchanged

Question 55

Examples of non-random mating

Answer 55

female mate choice and male-male competition

Question 56

When the probability of mating is not the same among individuals

Answer 56

Non-random mating

Question 57

Three major factors that alter allele frequencies and bring about most evolutionary changes

Answer 57

1. natural selection 2. genetic drift 3. gene flow

Question 58

Genetic drift

Answer 58

unpredictable changes in allele frequencies dut to change alone (not by inherited trait)

Question 59

Genetic drift is random with respect to...

Answer 59

fitness

Question 60

Genetic drift occurs...

Answer 60

in every population in every generation

Question 61

Important points about genetic drift

Answer 61

1. is random fluctuation in allele frequencies 2. removes genetic variation from the population 3. more powerful in small populations

Question 62

Founder Effect

Answer 62

a few individuals become isolated from the source population and differs genetically from the source

Question 63

Genetic Bottleneck

Answer 63

sudden reduction in population size (catastrophic event) results in drastic change in gene pool

Question 64

Gene flow

Answer 64

transfer of alleles into or out of a population due to the movement of fertile individuals or gametes

Question 65

Natural selection

Answer 65

differential success in reproduction results in certain alleles being passed to the next generation in greater proportions

Question 66

The only mechanism that consistentl causes adaptive evolution

Answer 66

Natural selection

Question 67

adds variation and can act antagonistically

Answer 67

gene flow

Question 68

removes variation and may or may not cause an increase in beneficial or harmful alleles

Answer 68

genetic drift

Question 69

Relative fitness

Answer 69

contribution an individual makes to the gene pool of the next generation relative to the contribution of other individuals

Question 70

Types (modes) of Natural Selection

Answer 70

1. Directional selection 2. Disruptive selection 3. Stabilizing selection

Question 71

Directional selection

Answer 71

occurs when selection favors one extreme phenotype over another

Question 72

Disruptive selection

Answer 72

occurs when selection favors extreme phenotypes over intermediate phenotpes

Question 73

Stabilizing selection

Answer 73

occurs when selection favors intermediate phenotype over the extremes