Genetics and Evolution

Question 1

contain genes in a linear sequence

Answer 1

chromosomes

Question 2

alternative forms of a gene

Answer 2

alleles

Question 3

the combination of alleles one has at a given genetic locus

Answer 3

genotype

Question 4

occurs when the effect of one allele completely masks the effect of another

Answer 4

complete dominance

Question 5

occurs when there is more than one dominant allele

Answer 5

codominance

Question 6

occurs when there are no dominant alleles; heterozygotes have intermediate phenotypes

Answer 6

incomplete dominance

Question 7

the proportion of a population with a given genotype who express the phenotype

Answer 7

penetrance

Question 8

refers to the varying phenotypic manifestations of a given genotype

Answer 8

expressivity

Question 9

states that an organism has two alleles for each gene, which segregate during meiosis, resulting in gametes carrying only one allele for a trait

Answer 9

Mendel’s first law (of segregation)

Question 10

states that inheritance of one allele does not influence the probability of inheriting an allele for a different trait

Answer 10

Mendel’s second law (of independent assortment)

Question 11

support for DNA as genetic material:
demonstrated the transforming principle, converting nonvirulent live bacteria into virulent bacteria by exposure to heat-killed virulent bacteria

Answer 11

Griffith experiment

Question 12

support for DNA as genetic material:

demonstrated that DNA is the genetic material because degradation of DNA led to a cessation of bacterial transformation

Answer 12

Avery-MacLeod-McCarty experiment

Question 13

support for DNA as genetic material:
confirmed that DNA is the genetic material because only radio-labeled DNA could be found in bacteriophage-infected bacteria

Answer 13

Hershey-Chase experiment

Question 14

includes all of the alleles in a given population

Answer 14

gene pool

Question 15

changes in DNA sequence

Answer 15

mutations

Question 16

include point mutations and frameshift mutations

Answer 16

nucleotide mutations

Question 17

nucleotide mutations:

the substituting of one nucleotide for another

Answer 17

point mutations

Question 18

nucleotide mutations:

moves the three-letter transcriptional reading frame

Answer 18

frameshift mutation

Question 19

nucleotide mutations:

has no effect on the protein

Answer 19

silent mutation

Question 20

nucleotide mutations:

results in the substitution of one amino acid for another

Answer 20

missense mutation

Question 21

nucleotide mutations:

results in the substitution of a stop codon for an amino acid

Answer 21

nonsense mutation

Question 22

nucleotide mutations:

result in a shift in the reading frame, leading to changes for all downstream amino acids

Answer 22

insertions and deletions (indels)

Question 23

include larger scale mutations affecting whole segments of DNA

Answer 23

chromosomal mutations

Question 24

chromosomal mutations:

occur when a large segment of DNA is lost

Answer 24

deletion mutations

Question 25

chromosomal mutations: | occur when a segment of DNA is copied multiple times

Answer 25

duplication mutation

Question 26

chromosomal mutations: | occur when a segment of DNA is reversed

Answer 26

inversion mutation

Question 27

chromosomal mutations: | occur when a segment of DNA is moved from one chromosome to another

Answer 27

insertion mutations

Question 28

chromosomal mutations: | occur when a segment of DNA is swapped with a segment of DNA from another chromosome

Answer 28

translocation mutations

Question 29

a flow of genes between species through hybrid offspring

Answer 29

genetic leakage

Question 30

occurs when the composition of the gene pool changes as a result of chance

Answer 30

genetic drift

Question 31

results from bottlenecks that suddenly isolate a small population, leading to inbreeding and increased prevalence of certain homozygous genotypes

Answer 31

founder effect

Question 32

visually represent the crossing of gametes from parents to show relative genotypic and phenotypic frequencies

Answer 32

Punnett squares

Question 33

cross that accounts for one gene

Answer 33

monohybrid cross

Question 34

cross that accounts for two genes

Answer 34

dihybrid cross

Question 35

cross that usually uses sex chromosomes to indicate sex as well as genotype

Answer 35

sex-linked crosses

Question 36

is the likelihood of two alleles being separated during crossing over in meiosis

Answer 36

recombination frequency (θ)

Question 37

can be made using recombination frequency as the scale in units of centimorgans

Answer 37

genetic maps

Question 38

states that if a population meets certain criteria (aimed at a lack of evolution), then the allele frequencies will remain constant, in ____ equilibrium

Answer 38

Hardy-Weinberg principle

Question 39

states that chance variations exist between individuals and that advantageous variations (those that increase an individual's fitness for survival or adaptation to the environment) afford the most opportunities for reproductive success

Answer 39

modern synthesis model (neo-Darwinism)

Question 40

considers an organism's success to be based on the number of offspring, success in supporting offspring, and the ability of offspring to then support others; survival of offspring or relatives ensures appearance of genes in subsequent generations

Answer 40

inclusive fitness

Question 41

considers evolution to be a very slow process with intermittent rapid bursts of evolutionary activity

Answer 41

punctuated equilibrium

Question 42

mode of natural selection: | keeps phenotypes in a narrow range

Answer 42

stabilizing selection

Question 43

mode of natural selection: | moves the average phenotype toward one extreme

Answer 43

directional selection

Question 44

mode of natural selection: | moves the population toward two different phenotypes at the extremes and can lead to speciation

Answer 44

disruptive selection

Question 45

mode of natural selection: | the rapid emergence of multiple species from a common ancestor, each of which occupies its own ecological niche

Answer 45

adaptive radiation

Question 46

the largest group of organisms capable of breeding to form fertile offspring

Answer 46

species

Question 47

the formation of a new species through evolution

Answer 47

speciation

Question 48

may occur between species either prezygotically or postzygotically

Answer 48

reproductive isolation

Question 49

reproductive isolation: | prevent formation of the zygote completely

Answer 49

prezygotic mechanisms

Question 50

reproductive isolation: | allow for gamete fusion but yield either nonviable or sterile offspring

Answer 50

postzygotic mechanisms

Question 51

occurs when two species sharing a common ancester become more different

Answer 51

divergent evolution

Question 52

occurs when two species sharing a common ancestor evolve in similar ways due to analogous selection pressures

Answer 52

parallel evolution

Question 53

occurs when two species not sharing a recent ancestor evolve to become more similar due to analogous selection pressures

Answer 53

convergent evolution

Question 54

states the degree of difference in the genome between two species is related to the amount of time since the two species broke off from a common ancestor

Answer 54

molecular clock model

Question 55

speciation: occurs when two populations of the same species become physically isolated from one another and then diverge into two species

Answer 55

allopatric speciation

Question 56

speciation: | occurs when two populations of the same species occupying the same environment diverge into two species

Answer 56

sympatric speciation

Question 57

Hardy-Weinburg equation

Answer 57

p + q = 1 p^2 + 2pq + q^2 = 1 where: p^2 = frequency of AA 2pq = frequency of Aa q^2 = frequency of aa