Which of the following is generally not considered essential to explain the origin of life on Earth?

Which of the following is generally not considered essential to explain the origin of life on Earth? 

A. a reducing atmosphere
B. sexual reproduction
C. a suitable energy source
D. organic building block compounds
E. formation of a constraining lipid or protein boundary






Answer: B

The oldest microfossils are of

The oldest microfossils are of 

A. prokaryotes.
B. eukaryotes.
C. insects.
D. pollen grains.
E. small animals.





Answer: A

Industrial melanism is a term

Industrial melanism is a term 

A. describing the color change induced by living in industrialized areas.
B. explaining that the darker moths have higher mutation rates because of industrialization.
C. describing the evolutionary process in which initially light-colored organisms become dark as a result of natural selection.
D. explaining that the darker moths having higher reproductive success because of their pigmentation.
E. describing the widespread implementation of pollution controls.

Answer: C

The recessive phenotype of a trait occurs in 20% of a population. There are no selection pressures affecting this trait. What would be the expected frequency of the dominant allele after six generations of continued non-selection?

The recessive phenotype of a trait occurs in 20% of a population. There are no selection pressures affecting this trait. What would be the expected frequency of the dominant allele after six generations of continued non-selection? 

A. 0.2
B. 0.306
C. 0.447
D. 0.494
E. 0.553







Answer: E

Charles Darwin argued that evolution is accomplished by the process of natural selection. Which of the following is not important to the concept of natural selection?

Charles Darwin argued that evolution is accomplished by the process of natural selection. Which of the following is not important to the concept of natural selection? 

A. Most organisms are capable of producing more offspring than typically survive.
B. Phenotypic variation that an organism acquires in its lifetime is passed on to its offspring.
C. Phenotypic variation exists within populations.
D. Phenotypic variation can influence reproductive success.
E. Phenotypic variation within a species is due in part to inherited characteristics.

Answer: B

In disruptive selection, over time

In disruptive selection, over time 

A. a population goes extinct.
B. the most extreme outliers of a population are eliminated (e.g., the largest beaks and smallest beaks are eliminated).
C. the population is strongly selected for in one direction (e.g., larger beak size).
D. the population is strongly selected for in two directions (e.g., larger beak size and smaller beak size). E. a population increases its variation (e.g., a wide selection of all beak sizes).

Answer: D

The text discusses sickle-cell anemia, which is a classic example of

The text discusses sickle-cell anemia, which is a classic example of 

A. founder effect.
B. genetic bottleneck.
C. point mutation.
D. heterozygote advantage.
E. heterozygosity.





Answer: D

Although it was a rare trait in the mainland population, one of the original female mice is homozygous for very large ears. This will lead to a population with a higher incidence of big ears than the mainland population because of

After a coastal storm 3 deer mice (Peromyscus), huddled on a tree trunk, are carried many miles out to sea and wash ashore on a small island that has no mice, but does have habitat to support them. Two of the mice are female, and both mate with the only male.

Although it was a rare trait in the mainland population, one of the original female mice is homozygous for very large ears. This will lead to a population with a higher incidence of big ears than the mainland population because of 

A. bottleneck effect.
B. founder effect.
C. mutation.
D. genetic drift.
E. selection pressure.



Answer: B

Compared with Hardy-Weinberg predictions, populations that have practiced assortative mating have

Compared with Hardy-Weinberg predictions, populations that have practiced assortative mating have 

A. fewer homozygotes.
B. less natural selection.
C. more heterozygotes.
D. more homozygotes.
E. more mutations.

Answer: D

Cheetahs have been through a genetic bottleneck; evidence for this is that

Cheetahs have been through a genetic bottleneck; evidence for this is that 

A. little natural selection occurs in this species.
B. the body is long, thin, and graceful.
C. there is very little genetic variability.
D. these cats are members of an endangered species.
E. they originally came from small areas of Africa.

Answer: C

Certain small towns in the western United States have remained isolated and inbred since their settlement many years ago. Some alleles are more common in these communities as compared to the rest of the population. This effect is known as

Certain small towns in the western United States have remained isolated and inbred since their settlement many years ago. Some alleles are more common in these communities as compared to the rest of the population. This effect is known as 

A. artificial selection.
B. directional selection.
C. disrupting selection.
D. Hardy-Weinberg principle.
E. founder principle.






Answer: E

When selection acts to eliminate one extreme from an array of phenotypes it is called

When selection acts to eliminate one extreme from an array of phenotypes it is called 

A. natural selection.
B. stabilizing selection.
C. disruptive selection.
D. directional selection.
E. artificial selection.





Answer: D

About 80% of the alleles present in thoroughbred horses can be dated back to 31 known ancestors from the late eighteenth century. As a result, one would expect

About 80% of the alleles present in thoroughbred horses can be dated back to 31 known ancestors from the late eighteenth century. As a result, one would expect 

A. low rates of mutation.
B. many polymorphic alleles.
C. little variation in physiology and behavior.
D. Hardy-Weinberg equilibrium.
E. random mating.

Answer: C

Which one of the following is not an agent of evolutionary change?

Which one of the following is not an agent of evolutionary change? 

A. mutation
B. gene flow
C. random mating
D. genetic drift
E. selection







Answer: C

In some populations the drive is to mate with individuals that are phenotypically different at a variety of loci. This leads to large numbers of heterozygotes and is called

In some populations the drive is to mate with individuals that are phenotypically different at a variety of loci. This leads to large numbers of heterozygotes and is called 

A. neutral theory.
B. disassortative mating.
C. shifting balance theory.
D. bottleneck effect.
E. founder effect.




Answer: B

Hardy-Weinberg pointed out that the original proportions of the genotypes in a population would remain constant from generation to generation if certain assumptions are met. Which one of the following is not a Hardy-Weinberg condition?

Hardy-Weinberg pointed out that the original proportions of the genotypes in a population would remain constant from generation to generation if certain assumptions are met. Which one of the following is not a Hardy-Weinberg condition? 

A. The population is very large.
B. No gene flow occurs.
C. No selection occurs.
D. Random mating occurs.
E. No polymorphic loci exist in the population.

Answer: E

In the Hardy-Weinberg equations, the frequencies of 2 alleles in a population (where there are only 2 alleles to consider) can be designated as

In the Hardy-Weinberg equations, the frequencies of 2 alleles in a population (where there are only 2 alleles to consider) can be designated as 

A. (p + q)2.
B. p and q.
C. p2 and q2.
D. 2pq.
E. 1 - p and 1 - q.






Answer: B

Natural selection is based on all of the following except:

Natural selection is based on all of the following except:

A. Populations tend to produce more individuals that the environment can support.

B. Variation exists within populations.

C. Use or disuse of organs during one generation causes modifications of these same organs in subsequent generations.

D. The fittest individuals leave the most offspring.

E. There is differential reproductive success within populations.

Answer: C

A virgin pine forest covers a valley, and one of the inhabitants is a red squirrel species. A large volcanic eruption occurs and separates the valley with a huge lava flow that the squirrels cannot cross, thus producing two isolated populations of squirrels. What change needs to occur for the two populations of squirrels to become separate species?

A virgin pine forest covers a valley, and one of the inhabitants is a red squirrel species. A large volcanic eruption occurs and separates the valley with a huge lava flow that the squirrels cannot cross, thus producing two isolated populations of squirrels. What change needs to occur for the two populations of squirrels to become separate species? 

A. The two squirrel populations must eat distinct species of plants.

B. The area that the squirrel populations occupy changes so that the squirrel populations exist in distinct habitats.

C. The fur color of the two squirrel populations must become distinct.

D. The two squirrel populations select mates using the same sexual behavior.

E. The two squirrel populations become reproductively isolated.

Answer: E

Sympatric speciation can involve all of the following except

Sympatric speciation can involve all of the following except 

A. disruptive selection.
B. reproductive isolating mechanisms.
C. autopolyploidy.
D. two or more populations separated by a geographic barrier.
E. allopolyploidy.

Answer: D