Question 1

Which of these statements best describes the phenomenon of antibiotic resistance in bacteria?

Accepted Answer

A)  For a particular antibiotic, all bacteria are either completely resistant or completely sensitive. 
B)  When a type of bacteria is resistant to antibiotics, it's resistant to all antibiotics. 
C)  Resistance is a matter of degrees; resistance can be partial or total, and resistance to each antibiotic is a separate trait. 
D)  Resistance to antibiotics is a trait that didn't exist before antibiotics were developed for pharmaceutical use.

Question 2

In 2005, a strain of extremely drug-resistant bacteria was isolated from a man in New York City. Public health officials braced themselves for many more cases, but they never appeared. What is the most likely explanation?

Accepted Answer

A)  The strain must have reverted back to a sensitive strain in order to keep infecting more people. 
B)  The strain may have been less fit in other ways and thus not successful in the population. 
C)  The strain must have become extinct. 
D)  The strain must have been dormant and was waiting for the right conditions to reappear.

Question 3

Any individual organism has the potential to evolve if it's given enough time and possesses a mechanism to generate variation.

Accepted Answer

A) True 
 B)False

Question 4

Artificial selection occurs when an organism's fitness is controlled by ________.

Accepted Answer

The answer of Artificial selection occurs when an organism's fitness...

Question 5

Many variants are produced during the long course of an HIV infection. Which of these variants would be most fit in the environment of the human body?

Accepted Answer

A)  a virus that infects liver cells 
B)  a virus that reproduces very slowly 
C)  a virus that makes fewer mistakes when replicating its RNA 
D)  a virus that can't be recognized by the patient's immune system

Question 6

Which of the following describes natural selection?

Accepted Answer

A)  A population of a mammal species varies in the length of their legs; water levels rise and the habitat becomes swampy; the individuals with shorter legs are better able to swim to food; the population evolves to become shorter-legged. 
B)  A population of a mammal species lives near the water; water levels rise and the habitat becomes swampy; the animals have trouble moving in the water; the population changes to a shorter-legged type so they can move more easily in the water. 
C)  Water levels rise and a habitat becomes swampy; a population of a mammal species on high ground observes the change; individuals with shorter legs migrate to the area. 
D)  A population of a mammal species lives near the water; water levels rise and the habitat becomes swampy; the act of swimming shortens the legs of the mammals; the offspring of the mammal species have shorter legs.

Question 7

Which of the following is the most direct (or first)result of natural selection on a population?

Accepted Answer

A)  New alleles are created when confronted with a new environment. 
B)  Proteins lose some functions. 
C)  The frequency of some alleles changes in the population. 
D)  Members of the population start reproducing more rapidly.

Question 8

In order for the theory of common descent and the theory of natural selection to both be true, what can we infer about the genetic material for all life?

Accepted Answer

A)  It must change very rarely. 
B)  It must vary spontaneously and randomly. 
C)  It must be transferrable between adults. 
D)  It must be transferable between different species.

Question 9

Which of the following is an example of jury-rigged design, or an adaptation that is constrained by the particular ancestral structure of the organism?

Accepted Answer

A)  antibiotic resistance in bacteria 
B)  anatomy that allows upright posture in humans 
C)  the wings of bats 
D)  ethanol tolerance in fruit flies

Question 10

What is the primary body part affected by tuberculosis?

Accepted Answer

A)  the liver 
B)  the muscles 
C)  the immune system 
D)  the lungs

Question 11

-What is shown in this figure?

Accepted Answer

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

Question 12

Which of the following is able to evolve?

Accepted Answer

A)  individual cats in a home 
B)  a population of asexually reproducing bacteria 
C)  a rose bush 
D)  an HIV virus that has infected a patient

Question 13

What causes the disease tuberculosis?

Accepted Answer

A)  a particular type of virus 
B)  a particular type of bacteria 
C)  exposure to polluted air 
D)  genetics

Question 14

Why is combination drug therapy less likely to lead to resistance than single drug therapy?

Accepted Answer

A)  In the presence of multiple drugs, the mutation rate of HIV decreases. 
B)  The drugs improve the immune system so that it's better able to find and remove virus particles. 
C)  The likelihood of one virus spontaneously mutating to be resistant to three different drugs is extremely small. 
D)  There are fewer side effects associated with combination drug therapy, and the appearance of resistance is directly proportional to the severity of side effects.

Question 15

The phrase "survival of the fittest" is somewhat misleading because

Accepted Answer

A)  it implies that the best possible organism will evolve. 
B)  it implies that organisms will always grow bigger and more complex. 
C)  it implies that there's random generation of variation. 
D)  it implies that humans are the proper end result of evolution.

Question 16

Any allele that's present in a population exists because it increases fitness.

Accepted Answer

A) True 
 B)False

Question 17

How did an understanding of genetics lead to "the modern synthesis"?

Accepted Answer

A)  It showed how traits could be passed from one organism to the next. 
B)  It showed how many offspring a single individual was capable of producing. 
C)  It showed the extent of variation for many traits. 
D)  It showed the kind of environmental change that could cause evolution.

Question 18

Natural selection occurs so an organism can become perfectly adapted to its environment.

Accepted Answer

A) True 
 B)False

Question 19

The blueberries found in a typical grocery store have several gene differences compared to wild blueberries. What has caused this difference?

Accepted Answer

A)  natural selection 
B)  artificial selection 
C)  a change in the environment 
D)  genetic engineering

Question 20

In what way is artificial selection different from natural selection?

Accepted Answer

A)  There's no difference; both have caused evolution throughout the history of life on Earth. 
B)  Artificial selection applies to changes in domestic animals only, while natural selection applies to all other species. 
C)  In artificial selection, human preference is the selecting force; in natural selection, environmental conditions are the selecting force. 
D)  Artificial selection causes one species to change to another, while natural selection only modifies existing species.

Exam 11: An Evolving Enemy: Natural Selection

Which of these statements best describes the phenomenon of antibiotic resistance in bacteria?

In 2005, a strain of extremely drug-resistant bacteria was isolated from a man in New York City. Public health officials braced themselves for many more cases, but they never appeared. What is the most likely explanation?

Any individual organism has the potential to evolve if it's given enough time and possesses a mechanism to generate variation.

Artificial selection occurs when an organism's fitness is controlled by ________.

Many variants are produced during the long course of an HIV infection. Which of these variants would be most fit in the environment of the human body?

Which of the following describes natural selection?

Which of the following is the most direct (or first) result of natural selection on a population?

In order for the theory of common descent and the theory of natural selection to both be true, what can we infer about the genetic material for all life?

Which of the following is an example of jury-rigged design, or an adaptation that is constrained by the particular ancestral structure of the organism?

What is the primary body part affected by tuberculosis?

-What is shown in this figure?

Which of the following is able to evolve?

What causes the disease tuberculosis?

Why is combination drug therapy less likely to lead to resistance than single drug therapy?

The phrase "survival of the fittest" is somewhat misleading because

Any allele that's present in a population exists because it increases fitness.

How did an understanding of genetics lead to "the modern synthesis"?

Natural selection occurs so an organism can become perfectly adapted to its environment.

The blueberries found in a typical grocery store have several gene differences compared to wild blueberries. What has caused this difference?

In what way is artificial selection different from natural selection?