Exam 2 ch 7

Question 1

constant frequency of an allele in a population over time

Answer 1

genetic equilibrium

Question 2

the movement of alleles from one population to another

Answer 2

migration

Question 3

hardy Weinberg assumes that for genetic equilibrium there must be no?

Answer 3

migration

Question 4

migration changes?

Answer 4

the allele frequencies in a population

Question 5

For small populations receiving immigrants from large source populations, migration can be a potent?

Answer 5

mechanism of evolution

Question 6

In groups of populations, gene flow (migration) tends to _________________________________ preventing the evolutionary divergence of populations.

Answer 6

homogenize allele frequencies

Question 7

Migration is most important in preventing populations from __________(evolving into separate
species)

Answer 7

diverging

Question 8

Humans are creating isolated populations, limiting migration and gene pools, and ________________________ of surviving isolated populations

Answer 8

increasing evolutionary divergence

Question 9

Random change in allele frequency due to chance; results in nonadaptive evolution

Answer 9

genetic drift

Question 10

can cause the disappearance or fixation of alleles

Answer 10

genetic drift

Question 11

When an allele becomes the only variant that exists for that gene in a population

Answer 11

fixation

Question 12

what causes random fixation

Answer 12

drift

Question 13

the fixation of a mutated version of a gene

Answer 13

substitution

Question 14

random discrepancies between theoretical and observed values

Answer 14

sampling error

Question 15

Sampling error can result in

Answer 15

genetic drift

Question 16

Natural sampling errors example

Answer 16

earthquakes, floods, landslides, or other natural disasters subdivide a population

Question 17

A large-scale but short-term reduction in population size that eliminates many
alleles

Answer 17

genetic bottleneck

Question 18

After first contacts with Europeans and Africans, _____________ of the native population of the New World died due to Old World
diseases

Answer 18

~90–95%

Question 19

Genetic drift that occurs when a few individuals become isolated from a larger population and form a new population whose gene pool composition is not reflective of the original
population

Answer 19

founder effect

Question 20

mutations that reduce the fitness of an individual are less likely to be transmitted to successive generations and the mutant trait will be quickly lost

Answer 20

Purifying Selection (Negative Selection)

Question 21

Mutations that increase the fitness of an individual are more likely to be transmitted to successive generations and the mutant trait is more likely to become fixed

Answer 21

positive selection

Question 22

When an allele changes frequency because a neighboring gene is undergoing a selective pressure

Answer 22

genetic hitchhiking

Question 23

Changes in a gene’s DNA sequence that do not change the amino acid

Answer 23

silent mutations

Question 24

Differences in the frequency of occurrence of synonymous codons in coding DNA

Answer 24

codon bias

Question 25

Codon bias is strongest in?

Answer 25

highly expressed genes

Question 26

Mating pattern in which some individuals are more or less likely to mate with
individuals of a particular genotype than with individuals of other genotypes

Answer 26

nonrandom mating

Question 27

Mating among genetic relatives

Answer 27

inbreeding

Question 28

self fertilization

Answer 28

selfing

Question 29

Reduced fitness in individuals because homozygotes for deleterious alleles
become more common or because heterozygotes have improved fitness

Answer 29

inbreeding depression