Deck 12: Mechanisms of Evolution

Question 1

An example of evolution that has been readily observed is

A) a chameleon changing colors as it moves from a leaf of one color to a leaf of another color.
B) increased resistance of bacteria to an antibiotic that is used to kill them.
C) chimpanzees learning sign language.
D) humans teaching dogs to obey certain commands.

Answer 1

B

Question 2

Evolutionary changes occur when ________ acts upon populations containing individuals with genetic differences.

A) continental drift
B) natural selection
C) weather
D) mutation

Answer 2

B

Question 3

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

A) 0.1
B) 0.3
C) 0.5
D) 0.7

Answer 3

D

Question 4

New alleles arise by

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

Question 5

When robins lay a clutch of more than four eggs,their chicks are often malnourished because they have so many to feed.If the robins lay fewer than four eggs,they may not have any viable offspring.As a result,robins typically lay a clutch of four eggs.This is an example of

A) disruptive selection.
B) directional selection.
C) stabilizing selection.
D) convergent evolution.

Question 6

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

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

Question 7

A gene has two alleles,D and

A) 0.2
B) 0.4
C) 0.64
D) 0.8
D) The frequency of the D allele is 0.2. What is the frequency of the d allele?

Question 8

Jean-Baptiste Lamark proposed that populations evolve when traits acquired during the lifetime of a parent are passed down to offspring.What is wrong with this proposal?

A) Only changes in the DNA sequence of an organism can be inherited. Traits acquired throughout life generally do not involve DNA.
B) The environment chooses which traits are necessary for survival rather than the individual.
C) Changes in a species occur at the individual level rather than at the population level.
D) The inheritance of acquired traits would not lead to speciation because it would cause all of the individuals in a population to become more similar.

Question 9

Alex is a student with Strep throat (caused by a strain of bacterium)who is given a prescription for an antibiotic and is told to take the drug for two weeks.After a week,he feels better and stops taking the drug.Two months later,Alex again shows symptoms of Strep throat and decides to finish the leftover antibiotic rather than going to the doctor again.Two months after that,he develops Strep throat for a third time and returns to the doctor.This time,the antibiotic does not work.The doctor runs a test and discovers that the bacterial strain Alex is carrying is antibiotic resistant.What most likely happened?

A) Because the use of antibiotics lowers the effectiveness of the immune system, the student continually reinfected himself with the bacteria. The third time, the student happened to be reinfected with a resistant strain.
B) When the student stopped taking the drug, a small number of bacteria-those that were more drug resistant-still survived in his body. Those bacteria repopulated his throat and, over time, drug-resistant alleles became more common.
C) The student must have eaten produce that had been genetically engineered with antibiotic-resistant genes. When he consumed them, the bacteria in the student's throat picked up these genes through horizontal gene transfer.
D) The antibiotic caused mutations in the bacterium. The more exposure to the antibiotic, the more mutations.

Question 10

Which of the following is true with regard to mutations?

A) Mutations occur in response to environmental pressures.
B) Mutations are more common in slowly growing organisms.
C) Mutations appear without regard to environmental pressures.
D) Several mutations must occur at one time for a new phenotype to appear.

Question 11

The population of a cactus species in a particular area has two to seven spines with an average of four spines per square centimeter of surface area.Cacti with fewer than four spines per square centimeter are more easily eaten by the wild boars thriving in the area.Over time,the population of this cactus species in this area have an average of six spines per square centimeter of surface area.This is an example of

A) disruptive selection.
B) directional selection.
C) stabilizing selection.
D) genetic drift.

Question 12

In natural selection,________ that increase survival and reproductive success become more common in a population.

A) genotypes
B) allele frequencies
C) bottlenecks
D) phenotypes

Question 13

Several related bird species live in a desert.One species is much smaller than the other species.This small species nests in holes in cacti.Because the bird is so small,it can easily squeeze between the spines of the cactus and create a well-protected nest.This is an example of

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

Question 14

In a shallow bay,a population of oysters is the food source for the local crabs.The lightest colored oysters blend with the color of the rocks and the darkest colored oysters are concealed in the shadows cast by the rocks.Oysters with an intermediate coloring are easily detected by the crabs and become a tasty meal for them.Over time,fewer and fewer oysters display the intermediate coloring while more oysters are either the lightest coloring or the darkest coloring.This is an example of

A) stabilizing selection.
B) directional selection.
C) disruptive selection.
D) genetic drift.

Question 15

Evolution can be described as

A) predesigned change in the genetic characteristics of a population of organisms over time.
B) sudden shifts in the genetic characteristics of an individual in a population.
C) a change in the genetic characteristics of a population of organisms over time.
D) isolation of populations due to geologic forces.

Question 16

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

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

Question 17

When individuals with intermediate values of an inherited phenotypic trait,like head circumference at birth,have an advantage over other individuals in the population,________ is the apparent pattern of natural selection.

A) genetic drift
B) disruptive selection
C) directional selection
D) stabilizing selection

Question 18

The color of a certain species of beetle is determined by a single gene.Two beetles homozygous for green coloration (meaning they have two copies of the green allele)produce a single offspring with brown coloration.Brown color appeared in this offspring as a result of

A) bottleneck.
B) gene flow.
C) genetic drift.
D) mutation.

Question 19

Insecticides are used to kill insects.However,insecticide-resistant insects are being found.What is the mechanism for this new insect trait?

A) An insect with a random mutation is not killed by the insecticide and reproduces.
B) Exposing insects to insecticides leads to mutations, which make the insects resistant.
C) Human interference with natural processes leads to genetic drift, which results in resistant insects.
D) Insecticides kill all the insects in a population, and a different species of resistant insects colonizes the available resources.

Question 20

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) both extremes of the phenotype are more successful.

Question 21

Convergent evolution occurs when natural selection causes distantly related organisms to

A) evolve into the same species despite the fact that they are members of separate populations.
B) merge into one continuous population because of reversals in continental drift.
C) evolve both analogous and homologous characteristics.
D) evolve similar structures in response to similar environmental challenges.

Question 22

During gene flow,

A) chance events alter the gene pool of a population.
B) new individuals contribute their alleles to the gene pool of a population.
C) alleles that make an individual more successful move from one population to another.
D) crossing-over creates new combinations of alleles during gamete formation.

Question 23

Two different species may have similar features because of

A) genetic drift.
B) the founder effect.
C) a bottleneck.
D) descent from a common ancestor.

Question 24

Some finches on the Galápagos Islands eat insects,an unusual food for finches to eat.These finches

A) evolved from a lineage of birds other than finches that ate insects.
B) learned their habits from local birds.
C) switched to insects because they tasted better than their usual food.
D) fill roles that birds other than finches would fill in other places.

Question 25

Which of the following is NOT likely to be a cause of rapid evolution in a population?

A) a changing environment
B) an organism that exhibits a rapid rate of mutation
C) an organism that reproduces very slowly
D) the immigration of individuals carrying a new allele that significantly increases reproductive success

Question 26

A mutation in a gene produces the identical protein to the original gene and,therefore,an identical trait.Will evolution act upon this mutation?

A) No, because evolution acts upon phenotypes.
B) Yes, because evolution acts upon phenotypes.
C) Yes, because mutations do contribute to evolution.
D) No, because mutations do not contribute to evolution.

Question 27

Gene flow occurs

A) as a result of genetic drift.
B) when an individual migrates between two otherwise isolated populations of a species.
C) as a result of mutations in one population but not in another.
D) when individuals within a population interbreed.

Question 28

The following image is an example of

A) gene transfer.
B) genetic drift.
C) natural selection.
D) mutation.

Question 29

While on a camping trip,Brian collects a white tadpole from a pond and takes it home.The tadpole develops into a white bullfrog.When the frog gets too big,he releases it 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 30

Both insects and humans evolved jointed legs to allow locomotion on land.These structures are considered analogous because insects and humans

A) stopped evolving at different times in Earth's history.
B) evolved from different ancestors.
C) cannot breed.
D) faced different environmental challenges during evolutionary time.

Question 31

The wings of a bird and the wings of a bat both form from the front appendages (arms).The bird wing is covered by feathers,and the bat wing consists of a thin layer of skin stretched between the "finger" bones.Are the wings of the bird and bat homologous or analogous?

A) homologous, because they evolved from the same body part
B) analogous, because birds' flight requires feathers and bats use skin; both are wings, but they evolved differently
C) both; they are homologous because they both evolved from a front appendage, but analogous because they evolved differently
D) neither, because birds and bats do not share a recent common ancestor

Question 32

Two unrelated species evolving to look more similar due to environmental pressures is called

A) gene flow.
B) genetic drift.
C) convergent evolution.
D) divergent evolution.

Question 33

Which of the following is NOT a cause of evolution?

A) mutation
B) gene flow
C) stable environmental conditions
D) sexual selection

Question 34

For a population to evolve,there must be genetic differences between organisms in that population.These differences arise by

A) mutation.
B) a change in an organism's behavior.
C) natural selection.
D) common descent.

Question 35

Genetic variation is based on

A) the inheritance of alleles accumulated during the lifetime of an individual.
B) differences in genotypes between the individuals in a population.
C) the accumulation of mutations in somatic cells (as opposed to gametes).
D) the formation of new combinations of alleles during asexual reproduction.

Question 36

Convergent evolution produces

A) genetic drift.
B) lines of common descent.
C) homologous characteristics.
D) analogous characteristics.

Question 37

Both mammals and octopi have evolved similar eye structures.This is an example of

A) convergent evolution.
B) divergent evolution.
C) disruptive selection.
D) directional selection.

Question 38

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

A) Mutation results in the formation of new alleles, and sexual reproduction results in new combinations of alleles.
B) New genes are introduced into a population when members of that population mate with members of other species and produce offspring.
C) Genetic variation is inherited by the next generation of a population.
D) Genetic drift, gene flow, and natural selection cause allele frequencies to change over time.

Question 39

UV light causes mutations within skin cells.Is UV light a major driving force in the evolution of animals?

A) Yes; UV light is always present outside and can produce both favorable and harmful mutations in skin cells. Only the favorable mutations will be passed on to the next generation.
B) Yes; a mutation in the skin cell will result in an organism that is better protected from the sun. This individual will be more likely to survive and pass on this mutation to the next generation.
C) No; only mutations in gametes will be passed on to the next generation. Only mutations that are passed on to offspring contribute to evolution.
D) No; only mutations that have a favorable adaptive quality will be passed on to the next generation. UV light produces only harmful mutations.

Question 40

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 41

How do natural selection and sexual selection differ?

A) Natural selection increases the frequency of alleles that contribute to survival, but sexual selection may increase the frequency of alleles that are not beneficial to survival.
B) Natural selection contributes to genetic drift, but sexual selection contributes to gene flow.
C) Natural selection is more random than sexual selection.
D) Natural selection increases the fitness of an allele, but sexual selection increases the dimorphism of an allele.

Question 42

The original source of genetic variation within a population is ________.

Question 43

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 44

Natural selection and other mechanisms of evolution act upon the ________ that result from the novel genotypes produced by mutations.

Question 45

Natural selection acts on ________ traits.By favoring certain phenotypes over others,the individuals having those phenotypes survive and reproduce at a higher rate than individuals who do not have those traits.

Question 46

Sexual selection can result in an increased frequency of alleles,which

A) may be harmful to the individual's survival but is always beneficial to its reproductive rate.
B) are always beneficial to the individual's survival but may be harmful to its reproductive rate.
C) are always beneficial to both the individual's survival and reproductive rates.
D) may be harmful to both the individual's survival and reproductive rates.

Question 47

A fisherman catches one trout from each of two ponds.Pond A contains 100 trout and pond B contains 1,000 trout.Which population is more affected by the fisherman?

A) Pond A; the fisherman has a greater likelihood of completely removing alleles from the gene pool by taking a fish from the smaller population.
B) Pond A; fewer fish are able to move into a small pond and find mates.
C) Pond B; the fisherman is more likely to catch a fish that is undergoing evolution in a bigger population.
D) Pond B; the process of evolution occurs more slowly in large populations and removing a fish speeds up the process.

Question 48

Compared to a large mainland population,genetic drift in a small island population is________ important because________.

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

Question 49

Evolution occurs when there are changes in the frequencies of alleles and genotypes in a(n)________ over time.

Question 50

The result of convergent evolution is ________ traits.

Question 51

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 52

When individuals with intermediate phenotypes have an advantage over all others in the population,such as the case with human birth weight in the 1930s-1940s,________ selection is the likely mechanism of evolution responsible.

Question 53

A population of 8,250 mice occupies the sand dunes in a coastal area.A severe hurricane washes out several miles of sand dunes.As a result,only 50 mice remain.The population has experienced

A) horizontal gene transfer.
B) gene flow.
C) a founder effect.
D) a bottleneck.

Question 54

A scientist is studying beak length in a species of hummingbird.The scientist establishes a population of birds with beaks ranging from very small to very long and allows the population to breed for 10 years.At the end of the experiment,she finds that the majority of birds in the population have very long beaks.This is an example of the ________ selection pattern of natural selection.

Question 55

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

Question 56

When similar environmental pressures,such as permafrost in low-altitude tundra and permafrost in high-altitude alpine tundra,cause genetically distantly related organisms to evolve similar structures for survival and reproduction under similar conditions,________ has occurred.

Question 57

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 58

A used car is shipped from Australia to the United States.Stowed away in the trunk of the car is a piece of wood infected with Australian termites.Once in the United States,the buyer of the car finds the rotting wood and dumps it on the side of the road.The termites survive and establish a colony on the side of the road but do not mate with local termite populations.This is an example of

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

Question 59

An example of gene flow would be if pollen from a population ________ plant lands on ________.

A) A; the same plant (mating with itself)
B) A; another population A plant
C) A; a population B plant
D) B; two other population B plants

Question 60

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

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

Question 61

Between 1980 and 1999,the Food and Drug Administration (FDA)approved 52 new antibacterial drugs.Only 8 new antibacterial drugs gained approval between 2000 and 2012.The lack of new antibacterial drugs may contribute to the ________ selection of antibiotic-resistant bacteria.

Question 62

Around 12,000 years ago,a massive extinction event decimated about 75 percent of the world's large mammal populations.A small number of cheetahs survived this event and began to reproduce.Discuss the implications of this event on the genetic diversity of today's cheetah population.

Question 63

Bees and hummingbirds are very good accidental pollinators.When they visit flowers to extract nectar,they pick up pollen from a flower and carry it to the next flower that they visit; this helps to distribute the pollen and the genes carried in the pollen to a different plant.Explain how bright red wildflowers that easily attract bees and hummingbirds might become more prevalent in a wildflower population of both red and white flowers through natural selection.

Question 64

In the figure below,the migrating bird is successful at introducing the recessive allele a into population 2 and producing offspring with the Aa genotype.Over time,these offspring mate with each other to produce offspring.Birds of various genotypes from both populations fly back and forth between the populations sharing alleles.Predict the outcome of genotype or allele frequency changes in these two populations after many generations.

Question 65

In an original population of 30 mice,the frequency of dark-fur-pigment alleles is 57% and the frequency of white-fur-pigment alleles is 43%.  Ten generations later,the population of 30 mice now has 28 dark-fur-pigment alleles and 32 white-fur-pigment alleles?  What are the new allele frequencies?  Is there evidence of ongoing evolution?  Explain.

Question 66

A chance evolutionary change occurring in small populations is referred to as ________.

Question 67

Explain why a mutation in an individual's skin cells does not directly contribute to evolution.

Question 68

Provide an example of analogous traits in two organisms and explain how/why those traits evolved in such distantly related organisms.

Question 69

Evaluate the accuracy of the following statement: "The natural selection of a prey species can be altered if a new predator is introduced." Explain how you reached your conclusion.

Question 70

MATCHING
Match each example to one of the processes below.
a.genetic drift
b.genetic bottleneck
c.founder effect
d.gene flow
e.natural selection
An area consists of dark and light rocks.Mouse populations that live on the dark rocks tend to be darkly colored; mouse populations that live on the light rocks tend to be lightly colored.

Question 71

Two populations of mice exist: one lives in an area with light rocks and the other lives in an area of dark rocks.A dark mouse from the population living on dark rocks migrates to the area of light rocks and breeds with mice there.Will this alter the allele frequency in the population? Discuss changes that may or may not be seen in the next generation and in following generations.

Question 72

New-world vultures are related to raptors,while old-world vultures are more closely related to storks.However,both of these birds eat carrion (decaying animals)and have a similar beak structure.Explain how this similarity in beak structures arose.

Question 73

Bacteria often store genes on small,circular pieces of DNA called plasmids.The process of transmitting these plasmids and the genes they contain to other bacteria is called ________ and is an example of gene flow.

Question 74

Compare and contrast bottleneck and founder effect.

Question 75

What pattern of natural selection is demonstrated by the information in the graph below? What is the selective pressure? What are the relative rates of evolution among the strains of bacteria? Provide your rationale.

Question 76

If the size of a population drops for at least one generation and causes a loss of genetic variation,a ________ occurs.

Question 77

Propose an explanation for why the circumference of newborn babies' heads would act as a stabilizing selective force in a population of humans that does not have access to modern medical care.

Question 78

A friend states,"Exposing bacteria to antibiotics causes the cells to mutate to become antibiotic resistant." Explain to your friend why he is incorrect and provide the correct explanation.

Question 79

Evaluate the accuracy of the following statement: "Individuals evolve by becoming more adapted to their environment." Explain how you reached your conclusion.

Question 80

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