Deck 15: How Populations Evolve

Question 1

A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, p2 represents:

A)the proportion of homozygous dominant individuals.
B)the decrease in heterozygous individuals.
C)the proportion of homozygous recessive individuals.
D)the increase in homozygous individuals.
E)the proportion of heterozygous individuals.

Answer 1

A

Question 2

The gene pool for a particular gene is made up of:

A)all the genes that occur in the population.
B)all the genes for a certain trait that occur in the population.
C)the sum of all the heterozygous individuals in the population.
D)the sum of all the homozygous individuals in the population.
E)all the alleles for a certain trait in a given individual.

Answer 2

A

Question 3

According to the Hardy-Weinberg principle, if 75% of the alleles in the gene pool are A1 and 25% are A2, what is the proportion of individuals with genotype A1A2 in this population?

A)0)1875
B)0)5625
C)0)375
D)0)0625
E)0)025

Answer 3

C

Question 4

An allele frequency is:

A)the number of all alleles in a population.
B)the relative proportion of a given allele in a population.
C)the sum of all genes in a population.
D)the number of different types of alleles in a population.

Question 5

A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, 2pq represents:

A)the proportion of homozygous dominant individuals.
B)the decrease in heterozygous individuals.
C)the proportion of homozygous recessive individuals.
D)the increase in homozygous individuals.
E)the proportion of heterozygous individuals.

Question 6

Which of the following is MOST likely to experience genetic drift?

A)a population of endangered birds that includes only five individuals
B)a population of common rodents that includes millions of individuals
C)a species of insect that occurs all across North America
D)a population of bears that is growing by thousands of individuals each year
E)a plant species that has spread to many different habitats all around the world

Question 7

Evolution can be defined as:

A)a change in the genetic makeup of a population over time.
B)a change in the phenotype of an individual over his or her lifetime.
C)a change in the genetic makeup of an organism over time.
D)an individual changing into another species.
E)one species diverging into two species.

Question 8

Inbreeding is defined as:

A)reproduction among unrelated individuals.
B)reproduction within a geographically isolated population.
C)sexual reproduction in a large population.
D)sexual reproduction among closely related individuals.
E)sexual population among unrelated individuals.

Question 9

Imagine that one of the original four mice that escape from a research lab is blind due to a genetic defect. If the mice breed and most of the mice born in subsequent generations are blind from birth, this is most likely a case of:

A)artificial selection.
B)the founder effect.
C)selective mutation.
D)an equilibrium population.
E)natural selection.

Question 10

A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, q2 represents:

A)the proportion of homozygous dominant individuals.
B)the decrease in heterozygous individuals.
C)the proportion of homozygous recessive individuals.
D)the increase in homozygous individuals.
E)the proportion of heterozygous individuals.

Question 11

In the context of evolution, equilibrium means:

A)no change in allele frequency.
B)no change in population size.
C)equal numbers of all alleles.
D)equal numbers of males and females.
E)no individuals move into or out of the population.

Question 12

Which of the following can evolve?

A)individuals
B)populations
C)genes
D)communities

Question 13

Populations of organisms are constantly evolving, which means they are always:

A)improving.
B)at equilibrium.
C)becoming more like humans.
D)getting bigger.
E)changing.

Question 14

In an equilibrium population:

A)mutation rates do not change.
B)natural selection occurs.
C)allele frequencies do not change.
D)population size cannot change.
E)rates of gene flow are constant.

Question 15

Within a large population, if no mutations occur, no migration occurs, all matings are random, and each individual has an equal chance of reproducing, which of the following will probably happen?

A)Extinction will result.
B)A bottleneck will occur.
C)Natural selection will occur at the normal rate for that species.
D)A change in allele frequency will lead to rapid evolution.
E)No evolution will occur.

Question 16

In a very small population of birds, assume 5 out of 20 alleles are the type that code for blue feathers. What is the allele frequency of the "blue feather allele" in this population?

A)0)20
B)0)25
C)0)40
D)0)50
E)5

Question 17

From an evolutionary point of view, what important process occurs when a young male baboon leaves the troop that he was born in to join another troop?

A)nonrandom mating
B)gene flow
C)the bottleneck effect
D)natural selection
E)genetic drift

Question 18

The interaction of genes and environment produces a specific:

A)genotype.
B)allele.
C)population.
D)phenotype.
E)gene pool.

Question 19

A population is defined as:

A)all individuals of the same species located throughout the world.
B)all individuals of the same species located in a given geographic region.
C)all individuals of all species located throughout the world.
D)all individuals of all species located in a given country.
E)those individuals of the same species that have an identical genetic makeup.

Question 20

Which of the following can cause evolutionary change in a small population?

A)genetic drift
B)lack of mutations
C)homozygous individuals
D)all recessive alleles
E)lack of gene flow

Question 21

Mutations:

A)can be helpful, neutral, or harmful to individuals.
B)arise due to environmental pressures.
C)are caused by natural selection.
D)limit the potential for evolution.

Question 22

Habitat loss, natural catastrophes, and/or excessive harvesting of a species often result in:

A)increased mutation rates.
B)population bottlenecks.
C)increased fitness of individuals.
D)artificial selection.
E)increased gene flow.

Question 23

Mutations are important because they:

A)provide variation that can result in evolutionary change.
B)occur in response to environmental demands.
C)are always beneficial in the individuals affected by them.
D)usually provide an individual with increased reproductive rates.

Question 24

Zoos often loan animals to other zoos for breeding purposes. From an evolutionary standpoint, what is the benefit?

A)New animals increase zoo revenues.
B)It increases the genetic diversity of the zoo's population.
C)It creates a bottleneck effect.
D)It increases the effects of natural selection on the population.
E)It increases the rate of random mutations.

Question 25

Shrews have been documented to travel across frozen lakes and establish populations on previously uninhabited islands. This is an example of:

A)genetic drift.
B)the founder effect.
C)a population bottleneck.
D)coevolution.
E)assortative mating.

Question 26

Imagine a population of monkeys in South America whose habitat has been reduced to the point where only 20 individuals survive. This is an example of:

A)genetic drift.
B)the founder effect.
C)natural selection.
D)a population bottleneck.
E)sexual selection.

Question 27

The process by which allele frequencies are altered in a population due to chance is called:

A)random evolution.
B)assortative evolution.
C)genetic drift.
D)random mutation.
E)fitness.

Question 28

Genetic drift results in a change in gene frequencies because:

A)gene flow within the population is less than gene flow between populations.
B)the population is so large that natural selection has little noticeable effect.
C)the population size is so small that chance occurrences can alter gene frequencies.
D)the population has not yet stabilized.

Question 29

Which of the following mutations would increase evolutionary fitness?

A)one that increases the life span of the organism
B)one that increases the birth weight of offspring while decreasing their number
C)one that increases the frequency of successful reproduction
D)one that attracts more potential mates without increasing the frequency of reproduction
E)one that removes other alleles from the population

Question 30

Gene flow:

A)prevents migration of individuals into other populations.
B)can spread certain alleles throughout a species.
C)isolates populations from one another.
D)negates the influence of evolution on a population.
E)limits evolutionary fitness.

Question 31

Male fish that display a bright blue color attract more mates as well as more predators. Maintaining that blue gene in the population is an example of:

A)the founder effect.
B)a population bottleneck.
C)coevolution.
D)genetic drift.
E)sexual selection.

Question 32

Having greater evolutionary fitness means:

A)having more offspring.
B)being stronger.
C)being able to produce more sperm or eggs.
D)being better able to survive.
E)being larger or faster.

Question 33

The Pennsylvania Amish have a very high frequency of an unusual allele that results in short arms and legs and extra fingers. This high frequency is thought to be the result of:

A)the founder effect.
B)nonrandom mutations.
C)a population bottleneck.
D)coevolution.
E)the addition of new members to an already established population.

Question 34

In general, each species of fruit fly in the Hawaiian archipelago is restricted to a single island. One hypothesis to explain this pattern is that new species formed after a small number of flies colonized each new island. This mechanism is called:

A)sexual selection.
B)genetic equilibrium.
C)artificial selection.
D)the founder effect.
E)assortative mating.

Question 35

Evolution by genetic drift is most obvious in:

A)large populations.
B)aquatic organisms.
C)small populations.
D)invertebrate species.
E)migratory species.

Question 36

Which of the following can be measured to estimate an organism's evolutionary fitness?

A)the number of offspring it produces over its lifetime that survive to breed
B)the number of offspring it produces over its lifetime
C)the number of eggs it produces over its lifetime
D)the size of its offspring
E)the number of gametes it produces over its lifetime

Question 37

Which of the following is an example of assortative mating?

A)A dominant male elephant mates with most females in a group, excluding other males from mating with the females.
B)A female mouse chooses a mate because he is the same color that she is.
C)A female sparrow chooses a mate because he attracts her by singing the correct song.
D)A female sheep chooses a mate because he has previously mated with many females.
E)A female lizard chooses to mate with the first male she encounters.

Question 38

The 30,000 elephant seals alive today are genetically very similar due to:

A)natural selection.
B)artificial selection.
C)the bottleneck effect.
D)the founder effect.
E)random mutation.

Question 39

The extreme loss of genetic diversity that has occurred in cheetah populations due to overhunting is the result of:

A)the founder effect.
B)a population bottleneck.
C)coevolution.
D)genetic drift.
E)natural selection.

Question 40

A bacterial allele that provides resistance to the antibiotic streptomycin:

A)is always beneficial to the bacterial cell.
B)is beneficial to the cell in the presence of streptomycin.
C)is neither beneficial nor detrimental to the cell.
D)is beneficial to the cell in the presence of any antibiotic.
E)is always detrimental to the cell.

Question 41

A new predator is introduced to an area that can feed on any millipedes shorter than 200 millimeters. No millipedes that live in that area are longer than 15 millimeters. What will happen?

A)All millipedes will be potential prey.
B)The millipedes will necessarily mutate to be longer.
C)Millipedes will necessarily evolve to avoid the predator.
D)Disruptive selection will favor 15-millimeter-long millipedes.
E)Directional selection will favor predators that consume the smallest millipedes.

Question 42

Evolution by natural selection is:

A)a rare event that has never been observed by scientists.
B)currently occurring but only in scientific laboratories.
C)constantly occurring at the same rate in all organisms.
D)a process that occurs as a result of differences in fitness.
E)a process that has occurred only in the past.

Question 43

Imagine that a population of hummingbirds with an intermediate beak size develops longer beaks over time. This is an example of:

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

Question 44

Which trait is the BEST example of an adaptation?

A)a new mutation that confers Tay-Sachs disease in humans
B)a mutation resulting in weak branches in a species of tree that lives in windy regions
C)a longer tongue in an insect-eating mammal that feeds on insects that live in shallow burrows
D)a mutation resulting in a heat-resistant enzyme in a bacterium living in a hot spring
E)a shorter neck in a giraffe that lives in an area with many rival males and tall trees

Question 45

In some butterfly populations, there are equal frequencies of alleles that code for black and yellow coloration. This is an example of:

A)sexual selection.
B)directional selection.
C)stabilizing selection.
D)nonrandom mutations.
E)balanced polymorphism.

Question 46

Female finches, which do not sing, tend to choose to mate with males who sing a specific, elaborate song. This is an example of:

A)coevolution.
B)fitness.
C)inbreeding.
D)assortative mating.
E)sexual selection.

Question 47

As predator and prey species acquire new adaptations to help them survive the constant "arms race" between them, what evolutionary phenomenon is occurring?

A)sexual selection
B)artificial selection
C)coevolution
D)competition
E)genetic drift

Question 48

Imagine that a species of bird with an intermediate beak size becomes two separate species with large and small beaks. This is an example of:

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

Question 49

In a certain species of salmon, some adult males are extremely large whereas other adult males are very small, compared to the females. There are no intermediate-sized adult males in the population. This is probably due to:

A)directional selection.
B)disruptive selection.
C)stabilizing selection.
D)artificial selection.

Question 50

The change in one population due to a change in another population is called:

A)coevolution.
B)assortative evolution.
C)genetic drift.
D)random mutation.
E)fitness.

Question 51

If two or more phenotypes in a population are both favored by selection, what is happening?

A)balanced polymorphism
B)directional selection
C)sexual selection
D)gene flow
E)stabilizing selection

Question 52

Natural selection selects for or against certain:

A)genotypes.
B)phenotypes.
C)gene pools.
D)populations.
E)alleles.

Question 53

The male peacock's beautiful tail is really a trade-off between:

A)artificial selection and natural selection.
B)natural selection and genetic drift.
C)sexual selection and natural selection.
D)disruptive selection and natural selection.

Question 54

The process by which allele frequencies are altered in a population to improve the odds of attracting a mate is called:

A)random evolution.
B)sexual selection.
C)genetic drift.
D)random mutation.
E)fitness.

Question 55

In one butterfly species, the colors of individuals range from white to black, with many shades of gray in between. If the butterflies in a mountain population become more and more similar in color over several generations (for example, if most butterflies are the same shade of gray), what kind of evolutionary force is likely acting on the population?

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

Question 56

The type of selection most likely to act on a well-adapted population in a relatively constant environment is:

A)artificial.
B)directional.
C)stabilizing.
D)disruptive.
E)nonrandom.

Question 57

The elaborate courtship displays common among animals are the result of:

A)random mating.
B)sexual selection.
C)spontaneous mutations.
D)stabilizing selection.
E)disruptive selection.

Question 58

If the tallest and shortest individuals of a population of humans do not survive and reproduce as well as the individuals of "average" height, which type of selection would most likely result?

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

Question 59

When a species lives in a constant environment for a long time, the "average type" of individual may have the best chance of surviving and producing the most offspring. What type of selection is occurring?

A)sexual
B)disruptive
C)stabilizing
D)directional
E)artificial

Question 60

Suppose a new mutation that improves metabolic efficiency is lost from a small population of mammals living in a region of seasonal food scarcity after a hurricane eliminates half the mammal population. This is an example of:

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

Question 61

The net migration of alleles into or out of a population from neighboring populations is called:

A)gene flow.
B)genetic drift.
C)sexual selection.
D)stabilizing selection.
E)coevolution.

Question 62

Imagine that a mutation for red eye color becomes very common in a population of flies because female flies in this population prefer to mate with red-eyed males. This is an example of:

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

Question 63

Multidrug-resistant bacteria:

A)have been eradicated worldwide.
B)are becoming less widespread.
C)have always been common in the natural environment.
D)are not serious threats to human health.
E)are becoming more widespread.

Question 64

Genetic drift is more common in large populations than in small populations. True or False?

Question 65

Suppose a population of mostly sand-colored crabs migrates from a sand beach to a pebble beach and evolves a darker, speckled coloration that closely resembles the pebble beach. This is an example of:

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

Question 66

The nonliving components of an environment, such as weather and water availability, are:

A)biotic components.
B)abiotic components.
C)genotypes.
D)phenotypes.
E)alleles.

Question 67

When one species evolves a new phenotypic feature and another species evolves new adaptations in response, it is called:

A)gene flow.
B)genetic drift.
C)sexual selection.
D)stabilizing selection.
E)coevolution.

Question 68

Bright coloration in birds makes them stand out to predators. In female birds that sit on the nest, bright coloration is rare because of:

A)gene flow.
B)natural selection.
C)artificial mutations.
D)stabilizing selection.
E)coevolution.

Question 69

Organisms that have the greatest reproductive success are considered the most evolutionarily fit. True or False?

Question 70

When natural selection tends to split a population into two phenotypic groups, it is called:

A)gene flow.
B)genetic drift.
C)balanced polymorphism.
D)stabilizing selection.
E)coevolution.

Question 71

Which of the following phenomena favors individuals with average phenotypes over those with extreme phenotypes?

A)gene flow
B)genetic drift
C)sexual selection
D)stabilizing selection
E)coevolution

Question 72

The use of antibiotics caused the mutation that produced MRSA. True or False?

Question 73

In a single family, the parents have brown eyes but all five of their children have green eyes. This is an example of evolution. True or False?

Question 74

Which of the following can affect a small, endangered population so severely that it goes extinct?

A)matings with a closely related species
B)increased mating opportunities
C)lost alleles and/or low genetic diversity
D)artificially adding new genes
E)sexual selection

Question 75

In a population, the most common phenotype represents the dominant allele. True or False?

Question 76

Natural selection causes genetic changes in populations. True or False?

Question 77

When different species closely interact for an extended period of time and develop new adaptations in response to each other, it is called:

A)gene flow.
B)genetic drift.
C)sexual selection.
D)stabilizing selection.
E)coevolution.

Question 78

The bright coloration of male birds is often the result of:

A)gene flow.
B)genetic drift.
C)sexual selection.
D)stabilizing selection.
E)coevolution.

Question 79

New individuals moving into an area and joining the breeding population are an example of gene flow. True or False?

Question 80

________ is due to chance events that change the allele frequencies in small populations.

A)Gene flow
B)Genetic drift
C)Sexual selection
D)Stabilizing selection
E)Coevolution