Question 1

Explain why new mutations appear frequently in bacterial populations but infrequently in human populations.

Accepted Answer

The answer of Explain why new mutations appear frequently in...

Question 2

A bacterial allele that provides resistance to the antibiotic streptomycin:

Accepted Answer

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 3

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

Accepted Answer

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

Question 4

A population is defined as:

Accepted Answer

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 5

According to the mathematical equation used in the Hardy-Weinberg principle, if the alleles for a certain trait in a population are A1 and A2, then the proportion of individuals with the genotype ________ is represented by 2pq.

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The answer of According to the mathematical equation used in...

Question 6

A city was intensively sprayed with the chemical DDT to control houseflies. The number of houseflies was immediately greatly reduced. Each year thereafter, the city was sprayed again, but the flies gradually increased in numbers until 10 years later they were as abundant as they were before the control program began. Provide an evolutionary explanation of what happened.

Accepted Answer

The answer of A city was intensively sprayed with the...

Question 7

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

Accepted Answer

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 8

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

Accepted Answer

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

Question 9

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

Accepted Answer

A) True 
 B)False

Question 10

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

Accepted Answer

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

Question 11

A population of plants comes in two flower colors: blue and white. Blue-flowered plants produce seeds that grow into both white and blue flowers. Crossing two white-flowered plants produces only white-flowering offspring. This indicates that the white-flowering plants are:

Accepted Answer

A) homozygous dominant for the flower color allele. 
B) homozygous recessive for the flower color allele. 
C) heterozygous for the flower color allele. 
D) mutating. 
E) in equilibrium.

Question 12

In the context of evolution, equilibrium means:

Accepted Answer

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 13

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?

Accepted Answer

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

Question 14

Evolutionary adaptations are not always the "best" solution to a problem. Explain how the long necks of giraffes can be both advantageous and disadvantageous.

Accepted Answer

The answer of Evolutionary adaptations are not always the "best"...

Question 15

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:

Accepted Answer

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

Question 16

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

Accepted Answer

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.

Question 17

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

Accepted Answer

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

Question 18

Gene flow:

Accepted Answer

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 19

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?

Accepted Answer

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

Question 20

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

Accepted Answer

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

Exam 15: How Populations Evolve