Question 1

Which factor would exert selection pressure on a population of insects?

Accepted Answer

A)  a new species of bird in the area 
B)  a fire 
C)  an earthquake 
D)  the introduction of a population of feral cats into the area 
A)  a new species of bird in the area 
B)  a fire 
C)  an earthquake 
D)  the introduction of a population of feral cats into the area

Question 2

A biologist has been studying two populations of trout in Montana for the last 25 years, when the two populations were established from one common population. In the southern population, the fish now have a slightly different mouth shape. But the northern population hasn't changed from the original type. The new shape works well in catching the type of prey common in the habitat of the southern population. Which is the best explanation for the gene differences in the two populations?

Accepted Answer

A)  The mutation only appeared in the southern population after it was exposed to the new prey. 
B)  The gene that produces the variation is probably still present in a small percentage of the northern population, but since there's no advantage to having it, individuals with the variation aren't selected. 
C)  The gene that produces the variation used to be present in a few individuals, but since it wasn't advantageous, individuals with that variation died out. 
D)  The gene that produces the variation used to be common in both populations, but since it wasn't advantageous in the northern population, the variation died out. 
A)  The mutation only appeared in the southern population after it was exposed to the new prey. 
B)  The gene that produces the variation is probably still present in a small percentage of the northern population, but since there's no advantage to having it, individuals with the variation aren't selected. 
C)  The gene that produces the variation used to be present in a few individuals, but since it wasn't advantageous, individuals with that variation died out. 
D)  The gene that produces the variation used to be common in both populations, but since it wasn't advantageous in the northern population, the variation died out.

Question 3

True or false: Once an adaptation appears, it remains in all the descendants unless the species becomes extinct.

Accepted Answer

A) True 
 B)False

Question 4

A city was intensively sprayed with 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, when they were almost as abundant as they were when the control program began. Which explanation applies to this situation?

Accepted Answer

A)  Flies from other areas moved in and replaced the ones killed by DDT. 
B)  The few flies that were affected by DDT but survived developed antibodies to DDT, which they passed on to their descendants. 
C)  The DDT caused new mutations to occur in the surviving flies, resulting in resistance to DDT. 
D)  The DDT killed most flies. The few that were already naturally resistant survived and passed this resistance on to their offspring. 
A)  Flies from other areas moved in and replaced the ones killed by DDT. 
B)  The few flies that were affected by DDT but survived developed antibodies to DDT, which they passed on to their descendants. 
C)  The DDT caused new mutations to occur in the surviving flies, resulting in resistance to DDT. 
D)  The DDT killed most flies. The few that were already naturally resistant survived and passed this resistance on to their offspring.

Question 5

Your friend was diagnosed with strep throat 2 months ago. She was treated with antibiotics for 10 days, but two weeks after treatment, the symptoms returned. She was given a different antibiotic and her symptoms improved again, initially, but then got worse. What is happening?

Accepted Answer

A)  Your friend has taken antibiotics so long that she has become tolerant to them, making them ineffective. 
B)  Exposure to antibiotics has caused each individual bacterial cell to evolve resistance to the antibiotics. 
C)  Your friend was originally infected with some bacteria that were resistant to these two antibiotics and the bacteria multiplied. 
D)  Your friend probably doesn't have a bacterial infection. There must be some other reason for her symptoms. 
A)  Your friend has taken antibiotics so long that she has become tolerant to them, making them ineffective. 
B)  Exposure to antibiotics has caused each individual bacterial cell to evolve resistance to the antibiotics. 
C)  Your friend was originally infected with some bacteria that were resistant to these two antibiotics and the bacteria multiplied. 
D)  Your friend probably doesn't have a bacterial infection. There must be some other reason for her symptoms.

Question 6

Which step in the theory of natural selection do humans impact the most to bring about artificial selection?

Accepted Answer

A)  Individuals in a population vary. 
B)  Some variation can be passed on to offspring. 
C)  Populations produce more offspring than the environment can support. 
D)  There is differential survival and reproduction among individuals in a population. 
A)  Individuals in a population vary. 
B)  Some variation can be passed on to offspring. 
C)  Populations produce more offspring than the environment can support. 
D)  There is differential survival and reproduction among individuals in a population.

Question 7

When a population of organisms is evolving, what can you be sure is happening?

Accepted Answer

A)  It's improving. 
B)  It's stable (no change). 
C)  It's getting bigger. 
D)  It's changing. 
A)  It's improving. 
B)  It's stable (no change). 
C)  It's getting bigger. 
D)  It's changing.

Question 8

Which plant is the most fit?

Accepted Answer

A)  a plant with deep roots 
B)  a plant with large leaves 
C)  a plant with large flowers 
D)  Environmental information is required to determine fitness. 
A)  a plant with deep roots 
B)  a plant with large leaves 
C)  a plant with large flowers 
D)  Environmental information is required to determine fitness.

Question 9

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

Question 10

Why is widespread resistance to tuberculosis (TB) not likely to evolve any time soon?

Accepted Answer

A)  Only a small percentage of people who are nonresistant to the bacterium will become infected and die from TB, so the variant will stay in the population. 
B)  TB is highly fatal, so those who are nonresistant will die quickly. 
C)  Humans are no longer evolving, so the population cannot develop widespread resistance. 
D)  It would be too expensive to genetically engineer people to give them the resistance gene. 
A)  Only a small percentage of people who are nonresistant to the bacterium will become infected and die from TB, so the variant will stay in the population. 
B)  TB is highly fatal, so those who are nonresistant will die quickly. 
C)  Humans are no longer evolving, so the population cannot develop widespread resistance. 
D)  It would be too expensive to genetically engineer people to give them the resistance gene.

Question 11

True or false: Any allele that's present in a population exists because it increases fitness.

Accepted Answer

A) True 
 B)False

Question 12

Why haven't humans evolved a resistance to the common cold?

Accepted Answer

A)  Colds are effectively killed by antibiotics, so there's no need. 
B)  Cold viruses haven't been in existence long enough to exert selective pressure. 
C)  Colds are not serious enough to remove nonresistant variants from the population. 
D)  We could evolve resistance if we stopped taking so many over-the-counter medications for colds. 
A)  Colds are effectively killed by antibiotics, so there's no need. 
B)  Cold viruses haven't been in existence long enough to exert selective pressure. 
C)  Colds are not serious enough to remove nonresistant variants from the population. 
D)  We could evolve resistance if we stopped taking so many over-the-counter medications for colds.

Question 13

What is the primary body part affected by tuberculosis?

Accepted Answer

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

Question 14

Which event 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. 
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 15

What traits increase fitness in a particular environment?

Accepted Answer

The answer of What traits increase fitness in a particular...

Question 16

Which sequence of events 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. 
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 17

If you wanted to see natural selection working in a population of mosquitoes in response to pesticide, how much pesticide should you use?

Accepted Answer

A)  enough to kill most but not all the mosquitoes 
B)  enough to kill all the mosquitoes 
C)  just enough so that the mosquitoes will be exposed but not enough to kill any of them 
D)  enough to kill the weakest 1% of the mosquitoes 
A)  enough to kill most but not all the mosquitoes 
B)  enough to kill all the mosquitoes 
C)  just enough so that the mosquitoes will be exposed but not enough to kill any of them 
D)  enough to kill the weakest 1% of the mosquitoes

Question 18

Why is the phrase "survival of the fittest" somewhat misleading?

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. 
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 19

Is it possible to prevent bacteria from becoming resistant to antibiotics?

Accepted Answer

A)  Yes: If we give antibiotics properly, resistance will go away and not evolve again. 
B)  No: Bacteria need to become resistant to anything that will kill them. 
C)  No: However, by using antibiotics properly, we can slow the rate at which resistance appears. 
D)  Yes: If we stop using antibiotics, the trait will disappear. 
A)  Yes: If we give antibiotics properly, resistance will go away and not evolve again. 
B)  No: Bacteria need to become resistant to anything that will kill them. 
C)  No: However, by using antibiotics properly, we can slow the rate at which resistance appears. 
D)  Yes: If we stop using antibiotics, the trait will disappear.

Question 20

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

Exam 11: An Evolving Enemy: Natural Selection

Which factor would exert selection pressure on a population of insects?

True or false: Once an adaptation appears, it remains in all the descendants unless the species becomes extinct.

Your friend was diagnosed with strep throat 2 months ago. She was treated with antibiotics for 10 days, but two weeks after treatment, the symptoms returned. She was given a different antibiotic and her symptoms improved again, initially, but then got worse. What is happening?

Which step in the theory of natural selection do humans impact the most to bring about artificial selection?

When a population of organisms is evolving, what can you be sure is happening?

Which plant is the most fit?

What causes the disease tuberculosis?

Why is widespread resistance to tuberculosis (TB) not likely to evolve any time soon?

True or false: Any allele that's present in a population exists because it increases fitness.

Why haven't humans evolved a resistance to the common cold?

What is the primary body part affected by tuberculosis?

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

What traits increase fitness in a particular environment?

Which sequence of events describes natural selection?

If you wanted to see natural selection working in a population of mosquitoes in response to pesticide, how much pesticide should you use?

Why is the phrase "survival of the fittest" somewhat misleading?

Is it possible to prevent bacteria from becoming resistant to antibiotics?

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

Can Science Cure the Common Cold Introduction to the Scientific Method

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Is It Possible to Supplement Your Way to Better Performance and Health

Body Weight and Health: Enzymes, Metabolism, and Cellular Respiration

Life in the Greenhouse: Photosynthesis and Climate Change

Cancer: DNA Synthesis, Mitosis, and Meiosis

Are You Only As Smart As Your Genes Mendelian and Quantitative Genetics

DNA Detective: Complex Patterns of Inheritance and Dna Profiling

Genetically Modified Organisms: Gene Expression, Mutation,

Where Did We Come From the Evidence for Evolution

Who Am I Species and Races

The Greatest Species on Earth Biodiversity and Classification

Is the Human Population Too Large Population Ecology

Conserving Biodiversity: Community and Ecosystem Ecology

Where Do You Live Climate and Biomes

Organ Donation: Tissues and Organs

Binge Drinking: the Digestive and Urinary Systems

Clearing the Air: Respiratory and Cardiovascular Systems

Vaccination: Protection and Prevention or Peril Immune System,

Human Sex Differences: Endocrine, Skeletal, and Muscular Systems

Is There Something in the Water Reproductive and Developmental Biology

Study Drugs: Brain Boost or Brain Drain Brain Structure and Function

Feeding the World: Plant Structure and Growth

Growing a Green Thumb: Plant Physiology

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