Deck 17: Evolution of Populations

Question 1

Which of the following is an example of gene flow?

A) Pollen from a population A plant lands on the same plant (mating with itself).
B) Pollen from a population A plant lands on another population A plant.
C) Pollen from a population A plant lands on a population B plant.
D) Pollen from a population B plant lands on a population B plant.

Answer 1

C

Question 2

If a given population has 30 RR individuals, 10 Rr individuals, and 10 rr individuals, what is the genotype frequency of Rr?

A) 0.10
B) 0.20
C) 0.30
D) 0.50

Answer 2

B

Question 3

New alleles arise by

A) nonrandom mating.
B) allele frequency.
C) genetic drift.
D) mutation.

Answer 3

D

Question 4

The human allele that causes six fingers per hand is dominant over the allele that produces five fingers per hand. Yet most humans have five fingers per hand. Why is this so?

A) A Punnett square shows this situation to be impossible.
B) The F2 generation never expresses the dominant trait.
C) The heterozygote expresses the recessive trait.
D) The six-finger allele exists at a low frequency in the human population.

Question 5

A population has a total of two alleles, G and g, for a given gene. Which one of the following sets of genotype frequencies is correctly expressed for that population?

A) GG = .25 Gg = .75 gg = .35
B) GG = .70 Gg = .25 gg = .30
C) GG = .75 Gg = .15 gg = .10
D) GG = .45 Gg = .15 gg = .75

Question 6

Which of the following processes does not lead to an increase in recombination?

A) fertilization
B) crossing over
C) independent assortment of chromosomes
D) DNA repair

Question 7

In the figure below, the flying bird moves permanently into the population shown on land.
As a result, the allele frequency of A changes from

A) 1 to 0.75.
B) 0 to 0.25.
C) 0 to 0.75.
D) 1 to 0.25.

Question 8

Which of the following is correct?

A) Giraffes did not evolve from other organisms.
B) Giraffes stretch to obtain food and for this reason their necks become longer. This characteristic is passed on to the next generation.
C) A giraffe's offspring are more likely to have longer necks than it does.
D) A giraffe's offspring, on average, will have necks of the same length that it has.

Question 9

Does sexual reproduction alone necessarily cause evolution?

A) Yes, sexual reproduction causes genetic drift.
B) Yes, sexual reproduction is the only source of new heritable mutations.
C) No, sexual reproduction creates variation, but evolution may or may not act on that variation.
D) No, sexual reproduction produces new combinations of alleles that are never subject to natural selection.

Question 10

In a population of 100,000 flies, 30,000 have the AA genotype, 20,000 carry the Aa genotype, and 50,000 have the aa genotype. What is the frequency of the A allele?

A) 1.00
B) 0.80
C) 0.40
D) 0.30

Question 11

Which of the following statements concerning evolution is false?

A) Natural selection requires variation in the population.
B) An individual that is better adapted than others in a population will always be more reproductively successful.
C) Genetic drift causes little evolutionary change in large populations.
D) Evolution involves a change of frequency of alleles in the gene pool.

Question 12

Microevolution

A) does not alter the genotype frequencies of a population.
B) is caused by speciation.
C) occurs only in microorganisms.
D) is the smallest scale at which evolution occurs.

Question 13

The genetic variation in a population is increased by

A) recombination.
B) allele fixation.
C) natural selection.
D) genetic drift.

Question 14

What is the total number of alleles for the T gene present in a population of 100 individuals?

A) 50
B) 100
C) 200
D) 400

Question 15

Which of the following factors is not likely to cause major changes in allele frequencies?

A) microevolution
B) gene flow
C) mutation
D) natural selection

Question 16

While on a camping trip, you collect some white tadpoles from a pond and take them home. The tadpoles develop into white bullfrogs. When the frogs get too big, you release them into a local pond. The next year, several white bullfrogs are observed in the pond. This is an example of

A) genetic drift.
B) natural selection.
C) gene flow.
D) sexual selection.

Question 17

Gene flow can occur when individuals move from one population to another. It can also occur

A) as a result of genetic drift.
B) if gametes, rather than individuals, move among populations.
C) as a result of mutations in one population but not in another.
D) when individuals within a population interbreed.

Question 18

If a given population has 30 RR individuals, 10 Rr individuals, and 10 rr individuals, what is the allele frequency of R?

A) 0.10
B) 0.30
C) 0.50
D) 0.70

Question 19

One factor that complicates the treatment of AIDS is the

A) low mutation rate of HIV.
B) high mutation rate of HIV.
C) random mating between viral particles.
D) non-random mating between viral particles.

Question 20

Gene flow between two populations

A) makes the genetic composition of the two populations more similar.
B) eliminates harmful alleles.
C) magnifies the effects of genetic drift.
D) creates genetic differences between the populations.

Question 21

Scientists studying the runoff of antibiotic resistance genes into ground water wells discovered in 2008 that concentrations of most resistance genes were diluted as water moved away from hog farms. One resistance gene, however, was found at higher concentrations in one well. Which of the following is a biologically valid explanation of this finding?

A) Exposure to antibiotics in their environment caused the bacteria naturally found in that well to mutate their DNA to create that antibiotic resistance gene.
B) The antibiotic resistance gene in the water was taken up by an organism living in that well. Since this gene helped the organism resist the antibiotics in the water, resistance was inherited by their offspring.
C) Hog gut bacteria that escaped into the water supply mated with other species of bacteria living in the well to create a "super-bacteria" containing the DNA of both species.
D) The herbicide resistance genes found in ground water well bacteria are easily converted to antibiotic resistance genes when an antibiotic is present in the environment.

Question 22

Genetic drift is caused by

A) small population size.
B) chance events.
C) gene flow.
D) large population size.

Question 23

If p is the frequency of the W allele in a population, why do we equate the WW individuals with the p² portion of the Hardy-Weinberg equation?

A) The Hardy-Weinberg equation describes the frequencies of dominant alleles only.
B) The WW individuals have two copies of the allele represented by p.
C) The ww individuals are all killed by lethal recessive genes.
D) The frequency of p is always equal to the frequency of q.

Question 24

In your backyard, you step on a dandelion and one of its seeds gets trapped in the tread of your shoes. The next day, you go on a long hike in the wilderness wearing the same shoes. When you step in a mud puddle, the seed sticks in the mud. The seed grows into a dandelion, but no other dandelions are present to mate with it. This is an example of

A) gene flow.
B) genetic drift.
C) natural selection.
D) sexual selection.

Question 25

Antibiotic resistance in bacteria could be combated by all of the following methods, except

A) investing money in the design of new drugs.
B) prescribing antibiotics only for bacterial diseases.
C) improving hospital sanitation.
D) prescribing antibiotics for viral diseases.

Question 26

Scientists have hypothesized that the reason European men have darker skin color than European women is that more than 10,000 years ago, these men preferred to mate with lighter-skinned females. If this is true, skin color is an example of ________ in Europeans.

A) gene flow
B) a genetic bottleneck
C) sexual selection
D) recombination

Question 27

Which of the following is not a mode of natural selection?

A) directional selection
B) disruptive selection
C) dormant selection
D) stabilizing selection

Question 28

Which of the following is not a step in the evolutionary process?

A) mutation and recombination occur at random in a population.
B) new genes are introduced into a population when members of that population mate with members of other species.
C) genetic variation is inherited by the next generation of a population
D) genetic drift, gene flow and or natural selection cause allele frequencies to change over time.

Question 29

The color of a certain species of beetle is determined by a single gene. Two beetles homozygous for green coloration produce a single offspring with brown coloration. Brown color appeared in this offspring as a result of a ___________.

Question 30

Although millions of prairie chickens once occupied Illinois, in 1993 only 50 remained. Starting in 1992, scientists moved almost 300 prairie chickens from large populations in other states to Illinois to ________________ Illinois prairie chicken populations.

A) prevent the development of nonheritable mutations in
B) introduce genetic variation back into
C) induce stabilizing selection in
D) cause genetic drift in

Question 31

Independent assortment of chromosomes, crossing-over, and fertilization are collectively known as _____________.

Question 32

The genetic variation of a population is a result of differences in the _______ sequences of individuals and provides the raw material for evolution.

Question 33

_______ are the original source of genetic variation within a population.

Question 34

Genetic drift has a greater effect on

A) moths than on birds.
B) individuals than on populations.
C) small populations than on large populations.
D) natural selection than on gene flow.

Question 35

Disruptive selection operates whenever

A) natural selection is disrupted by genetic drift.
B) there is a balanced gene pool.
C) only the smallest individuals survive.
D) the extremes in a distribution of phenotypes survive better than the average of a distribution.

Question 36

"Emigration" is the term that describes one or more individuals leaving their home population. Is the effect of emigration likely to have a greater genetic effect if the home population was large, or if the home population was small?

A) large, because this is an example of disruptive selection
B) large, because natural selection will cause a bottleneck to occur in the remaining individuals
C) small, because the loss of just a few individuals may greatly reduce the remaining genetic variation
D) small, because the remaining individuals will no longer be able to practice nonrandom mating

Question 37

What is genetic drift?

A) gene mutation within, or between, populations
B) chance evolutionary change occurring in small populations
C) natural selection acting on large populations
D) shifts in allelic frequencies due to mutation

Question 38

Compared to a large mainland population, genetic drift in a small island population is

A) less important because there is less variation with which to work.
B) less important because only a few individuals do all the breeding.
C) more important because of a smaller gene pool.
D) more important because of the absence of competition.

Question 39

A gene has two alleles, B and b. If the b allele becomes "fixed" in the population, its frequency will be _______ percent.

A) 0
B) 33.3
C) 50
D) 100

Question 40

According to the figure below, the r allele is less frequent in generation 2 of this flower population.
The frequency of r decreases in this population because

A) of genetic drift.
B) recessive alleles are always less common than dominant alleles.
C) p + q must always equal 1.
D) R alleles are more likely to "hide" r alleles in generation 2.

Question 41

The allele frequency of a recessive allele is always less than the allele frequency of a dominant allele.

Question 42

In any given population the genotype frequency is usually the same as the allele frequency.

Question 43

The occurrence of mutation is directed toward a specific goal.

Question 44

Individuals in a population have different DNA sequences for various genes than other individuals in the same population.

Question 45

A few members of a species establish themselves on a small island far from other populations of that species. They may experience a genetic bottleneck due to the _______ effect.

Question 46

Mutations generally cause rapid changes in allele frequencies in populations.

Question 47

When a population shrinks, causing low genetic variation or the fixation of a harmful allele, a genetic _______ has occurred.

Question 48

In many cases of ____________ selection, mates are chosen based on physical features or behaviors rather than fitness.

Question 49

Allele frequency refers to the rate of mutation in a population.

Question 50

Examine the graph below.

The shape of this graph indicates that birth weight in human babies is an example of _____________ selection.

Question 51

Although they are protected in many countries, humans still hunt elephants for their ivory tusks. A mutation that results in tusk-less elephants in increasing in frequency in some elephant populations as a result of the evolutionary mechanism of __________ __________.

Question 52

A new allele spreads from one large population to another as a result of genetic flow.

Question 53

Larger male elephant seals have more mates than smaller male elephant seals because they are better at defending their territory (and mates). This is an example of __________ ___________.

Question 54

Two populations of geese live near each other. As time passes, the populations are becoming more genetically alike. This is probably due to gene _______.

Question 55

In the Hardy-Weinberg equation, _______ represents the predicted frequency of the heterozygous genotype.

Question 56

In __________ selection individuals with one extreme of an inherited phenotypic trait have an advantage over other individuals in the population.

Question 57

Recombination usually reverses the effects of a mutation.

Question 58

Genetic drift causes random changes in _______ frequency.

Question 59

If the genotype values predicted by the Hardy-Weinberg equation are greatly different from the values found in the real population, we can say that the population is ________.

Question 60

________ _________ is the only mechanism of evolutionary change that is not influenced by chance events.

Question 61

Natural selection is a random process.

Question 62

In fish undergoing sexual selection, females are more likely to mate with males lacking coloration because brightly colored males are more visible to predators.

Question 63

The Hardy-Weinberg equation can be used to determine the genotype frequencies of a population that is not evolving.

Question 64

A gene has two alleles, D and d.The frequency of the D allele is 0.2. What is the frequency of the d allele? Show your work.