Deck 17: Microevolution

Question 1

A group of similar organisms that can successfully interbreed:

A) shares the same genotype.
B) shares the same phenotype.
C) is referred to as a species.
D) is very difficult to find in nature.

Answer 1

is referred to as a species.

Question 2

Which of the following categories is the smallest capable of evolution?

A) species
B) individual organism
C) family
D) population

Answer 2

population

Question 3

Populations of sexually reproducing organisms are continually evolving by which means?

A) They are getting bigger.
B) They are changing.
C) They are at equilibrium.
D) They are improving.

Answer 3

They are changing.

Question 4

Which phrase best defines gene pool?

A) all the alleles at one locus in a population
B) all the loci on one set of chromosomes in a population
C) a group of genes that drift and flow
D) all the alleles at all loci of all individuals of a population

Question 5

In which of the following scenarios would evolution by natural selection cease to occur?

A) Humans become extinct because of a disease epidemic.
B) A thermonuclear war killed most living organisms and changed the environment drastically.
C) Genetic recombination and mutation stopped, and organisms could reproduce only asexually.
D) Ozone depletion led to increased ultraviolet radiation, which caused many new mutations.

Question 6

Of the following mechanisms, which would prevent evolution from occurring in a population that reproduced only asexually.

A) random mating
B) mutation
C) gene flow
D) genetic drift

Question 7

What is the difference between microevolution and macroevolution?

A) Microevolution is hypothetical because changes are too small to be observed, whereas macroevolution is detectable.
B) Microevolution deals with microscopic organisms, whereas macroevolution deals with larger ones.
C) Microevolution describes what happens in small populations, whereas macroevolution deals with large populations.
D) It is a convenient, arbitrary distinction based on whether shorter or longer time periods of evolution are being considered.

Question 8

The fact that mutations are random and independent of "need implies that:

A) a population could become extinct because it lacks the variation to evolve.
B) every population must already contain all the variants of the alleles that it could ever potentially need.
C) a perfectly adapted population will have no variation.
D) mutation rate increases with environmental instability.

Question 9

Read the statement below and then answer the questions that follow. A small population of deer is introduced to an island. All the males have 11 to 13 points on their antlers.

-As the years go by, the environment on this island shows no significant evidence of change. If the deer herd reaches a stable population size, what kind of evolutionary force is likely to be acting on the population?

A) directional selection
B) disruptive selection
C) founder effect
D) stabilizing selection

Question 10

Refer to the table above and then answer the questions that follow.

-The only known population of a reptile species lives on an African mountain. The population is relatively large, but no close relatives of this species are known. Suppose you could stop all mutations within the population and all emigration out of this population. Which statement best describes the probable future of this population?

A) The population will deteriorate after a few generations because of excessive inbreeding.
B) Evolution will continue as selection acts on the variability produced by sexual recombination of genes.
C) Although the population will cease to change, it may survive for as long as the environment remains constant.
D) Genetic drift will cause major evolutionary changes in the population.

Question 11

Refer to the table above and then answer the questions that follow.

-Sexual displays and contests common in the Kingdom Animalia (such as bighorn sheep bashing their heads together) result in:

A) mutations.
B) nonrandom mating.
C) random mating.
D) stabilizing selection.

Question 12

Refer to the table above and then answer the questions that follow.

-Genetic drift results in a change in gene frequencies because:

A) the population size is so small that chance occurrences can alter gene frequencies.
B) reproduction is nonrandom within the population.
C) gene flow within the population is less than gene flow between populations.
D) the population has not yet stabilized.

Question 13

Elephants have a matriarchal society, and young males are driven out of the herd when they reach adulthood. From an evolutionary standpoint, what does this accomplish?

A) natural selection
B) formation of a more variable population
C) gene flow
D) nonrandom mating

Question 14

Populations of organisms undergo continual evolution, which means that:

A) they are growing in size.
B) they are at equilibrium.
C) they are changing.
D) they are getting better.

Question 15

Mutations:

A) are always detrimental.
B) occur to solve problems for species (are goal oriented).
C) are random.
D) are always beneficial.

Question 16

Which of the following is not a source of variation within a species or population?

A) meiosis
B) natural selection
C) mutation
D) sexual reproduction

Question 17

What do you think will happen in a population of frogs in which no mutations occur, no migrations happen, the adults mate randomly, and each frog has the same chance of reproducing?

A) A bottleneck will occur.
B) The frogs will become extinct.
C) Evolution will occur at the normal rate.
D) No evolution will occur.

Question 18

Microevolution is:

A) the addition of an acquired characteristic.
B) changes in allele frequency in individuals.
C) changes of allele frequency in populations.
D) creation of a new species.

Question 19

Which of the following would decrease genetic variation in a population?

A) mutation
B) genetic drift
C) gene flow
D) migration

Question 20

Refer to the following populations of a plant species and then answer the questions that follow.
1. 20 plants capable of asexual reproduction only.
2. 50 plants with unisexual flowers. Some plants bear male and some female flowers.
3. 1,000 plants with bisexual, self-fertilizing flowers.
4. 500 plants with bisexual, self-sterile flowers that make seeds only when cross-pollinated.

-Which population is most likely to change as a result of genetic drift?

A) 1
B) 2
C) 3
D) 4

Question 21

Refer to the following populations of a plant species and then answer the questions that follow.
1. 20 plants capable of asexual reproduction only.
2. 50 plants with unisexual flowers. Some plants bear male and some female flowers.
3. 1,000 plants with bisexual, self-fertilizing flowers.
4. 500 plants with bisexual, self-sterile flowers that make seeds only when cross-pollinated.

-The physical appearance of which population is most likely to be affected by the founder effect?

A) 1
B) 2
C) 3
D) 4

Question 22

Refer to the following populations of a plant species and then answer the questions that follow.
1. 20 plants capable of asexual reproduction only.
2. 50 plants with unisexual flowers. Some plants bear male and some female flowers.
3. 1,000 plants with bisexual, self-fertilizing flowers.
4. 500 plants with bisexual, self-sterile flowers that make seeds only when cross-pollinated.

-Which population would be most likely to survive in the event of a drastic environmental change?

A) 1
B) 2
C) 3
D) 4

Question 23

Refer to the following populations of a plant species and then answer the questions that follow.
1. 20 plants capable of asexual reproduction only.
2. 50 plants with unisexual flowers. Some plants bear male and some female flowers.
3. 1,000 plants with bisexual, self-fertilizing flowers.
4. 500 plants with bisexual, self-sterile flowers that make seeds only when cross-pollinated.

-Which population would probably show the most variation?

A) 1
B) 2
C) 3
D) 4

Question 24

Which of the following males in a given population would be considered the most fit in an evolutionary sense? One that produced:

A) 1,000 offspring, of which 100 survived but 99 did not reproduce.
B) 100 offspring, of which 10 survived but 9 did not reproduce.
C) 1,000 offspring all of which died before reaching reproductive age.
D) two offspring, both of which survived and produced offspring of their own.

Question 25

In central Africa, the frequency (percentage) of the sickle-cell gene, compared to the normal gene, has remained stable over the years because the sickle-cell gene protects against malaria. In the United States, malaria was eradicated shortly before World War II by eliminating the mosquito that spreads the disease. What has likely happened to the frequency of the sickle-cell gene in African Americans living in the United States since the elimination of malaria?

A) The sickle-cell gene has disappeared from the African American population.
B) The normal gene has disappeared from the African American population.
C) The frequency of the sickle-cell gene has increased.
D) The frequency of the sickle-cell gene has decreased.

Question 26

You are studying leaf size in a natural population of plants. The second season is particularly dry, and the following year the average leaf size in the population is smaller than the year before. But the amount of overall variation is the same, and the population size hasn't changed. Also, you've done experiments that show that small leaves are better adapted to dry conditions than are large leaves. Which of the following has occurred?

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

Question 27

The previously described state of the sickle-cell gene in African Americans since malaria was eliminated in the United States is an example of:

A) genetic drift.
B) disruptive selection.
C) the founder effect.
D) directional selection.

Question 28

The construction of housing developments on the beaches of southern California has resulted in the loss of areas with sufficient weeds to support certain butterflies. This can result in:

A) natural selection.
B) migration.
C) population bottlenecks.
D) increased mutation.

Question 29

Which of the following traits probably arose through sexual selection?

A) speed in cheetahs
B) camouflage in walking stick insects
C) brighter plumage in male birds than in female birds of the same species
D) migration in whales

Question 30

The common genetic defects of certain dog breeds are due to:

A) disruptive selection.
B) inbreeding.
C) mutation.
D) random mating.

Question 31

The evolutionary advantage of incest taboos in humans is that they protect against:

A) wasted energy.
B) the cost of inbreeding.
C) familial discord.
D) police charges.

Question 32

How efficient is sexual reproduction alone in gauging the frequency of an allele?

A) very efficient
B) barely efficient
C) not efficient at all

Question 33

Suppose we find a population with 60 AA individuals, 20 Aa individuals, and 20 aa individuals, what is the allele frequency of A?

A) 0.20
B) 0.40
C) 0.60
D) 0.70

Question 34

Suppose we find a population with 60 AA individuals, 20 Aa individuals, and 20 aa individuals, what is the genotype frequency of Aa?

A) 0.20
B) 0.40
C) 0.60
D) 0.70

Question 35

Nonrandom mating (for example, assortative mating) directly affects gene frequencies in populations.

Question 36

The process by which a species of bird with an intermediate beak size becomes two separate species with large and small beaks respectively is called disruptive selection.

Question 37

Match the following description with the term.

-A small number of individuals from one area establish a new isolated population in another area. The gene frequencies of the new population differ from those of the original population.

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

Question 38

Match the following description with the term.

-Females tend to mate with brightly colored males.

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

Question 39

Assume that protein synthesis always reads along a chromosome three bases at a time to code for each successive amino acid in a protein. There are two kinds of point mutations, a base substitution and a base deletion. How are these two types of mutations likely to affect the protein coded for by a mutated gene?

Question 40

Why do most human societies have laws or customs against marrying close relatives?

Question 41

Consider a species that becomes localized in its distribution and overspecializes in a particular type of food. How would this affect the likelihood that this species will become extinct?