Evaluate the Graph (Use this information for questions 2 - 10.)

Question

Imagine an island that has a deer population with no natural predators. To prevent the deer population from getting too large, wolves (predators) are placed on the island.



This graph shows how the populations of deer and wolves changed. The deer population scale is on the left. The wolf population scale is on the right.

Note that the populations would continue to oscillate (fluctuate up and down) in the future, but they would oscillate within a stable, healthy range as long as some other factor didn't suddenly influence their populations.



Important: Click here to watch a video to see an explanation of how to interpret this graph.

Question 1
2. Before the wolves were introduced, how was the deer population changing?(1 point)
Responses

The deer population was stable (staying roughly the same each year).
The deer population was stable (staying roughly the same each year).

The population change is unable to be determined with the data provided.
The population change is unable to be determined with the data provided.

The deer population was growing rapidly.
The deer population was growing rapidly.

The deer population was shrinking.
The deer population was shrinking.
Question 2
3. During the period when there were no wolves, what is the best explanation for WHY the deer population was changing in the way that it was changing?(1 point)
Responses

The deer were starving to death, so the deer population went up.
The deer were starving to death, so the deer population went up.

The deer didn't have any natural predators, so the deer population went down.
The deer didn't have any natural predators, so the deer population went down.

The deer didn't have any natural predators, so the deer population went up.
The deer didn't have any natural predators, so the deer population went up.

The deer were starving to death, so the deer population went down.
The deer were starving to death, so the deer population went down.
Question 3
4. If wolves had not been introduced, would the deer population have been able to grow at the same rate forever?(1 point)
Responses

Yes, the deer population would have grown quickly forever because nothing else limits population other than predators.
Yes, the deer population would have grown quickly forever because nothing else limits population other than predators.

No, the deer population would have grown quickly for a while but eventually would have been limited somewhat by lack of food and by disease.
No, the deer population would have grown quickly for a while but eventually would have been limited somewhat by lack of food and by disease.
Question 4
5. According to the graph above, in what year were the wolves introduced to the island?(1 point)
Responses

2008
2008

2010
2010

2012
2012

2014
2014
Question 5
6. What is the relationship between the wolves and the deer of the island?(1 point)
Responses

Wolves are prey and the deer are predators.
Wolves are prey and the deer are predators.

Wolves are predators and the deer are prey.
Wolves are predators and the deer are prey.

Wolves and deer mutually help each other.
Wolves and deer mutually help each other.

Wolves are parasites and the deer are the hosts.
Wolves are parasites and the deer are the hosts.
Question 6
7. Which description correctly describes predators and prey?(1 point)
Responses

Predators hunt, kill, and eat prey.
Predators hunt, kill, and eat prey.

Predators and prey compete with each other for all of the same biotic and abiotic resources.
Predators and prey compete with each other for all of the same biotic and abiotic resources.

Predators and prey do not interact with each other at all.
Predators and prey do not interact with each other at all.

Predators live on or in the prey causing the prey harm by feeding on it continually and eventually causing the prey to die.
Predators live on or in the prey causing the prey harm by feeding on it continually and eventually causing the prey to die.
Question 7
8. What happened between 2010 and 2015 on the island?(1 point)
Responses

As the wolf population grew, the wolves ate more deer.
As the wolf population grew, the wolves ate more deer.

As the wolf population decreased, the wolves ate fewer deer.
As the wolf population decreased, the wolves ate fewer deer.

As the wolf population decreased, the wolves ate more deer.
As the wolf population decreased, the wolves ate more deer.

As the wolf population grew, the wolves ate fewer deer.
As the wolf population grew, the wolves ate fewer deer.
Question 8
9. What happened between 2016 and 2020 on the island?(1 point)
Responses

The deer and wolf populations both shrank rapidly the whole time.
The deer and wolf populations both shrank rapidly the whole time.

It's not possible to determine how the populations changed.
It's not possible to determine how the populations changed.

The deer and wolf populations changed slowly and then stabilized.
The deer and wolf populations changed slowly and then stabilized.

The deer and wolf populations both grew rapidly the whole time.
The deer and wolf populations both grew rapidly the whole time.
Question 9
10. What is the most likely explanation for the way the graph looks for the period from 2018 to 2020?(1 point)
Responses

The wolf and deer populations were stabilized because all other predators and prey died.
The wolf and deer populations were stabilized because all other predators and prey died.

The wolf and deer populations were not stabilized because all the wolves stopped eating.
The wolf and deer populations were not stabilized because all the wolves stopped eating.

The wolf and deer populations were stabilized because the number of predators and the number of prey were well balanced.
The wolf and deer populations were stabilized because the number of predators and the number of prey were well balanced.

The wolf and deer populations were not stabilized because all the deer got better at hiding from wolves.
The wolf and deer populations were not stabilized because all the deer got better at hiding from wolves.
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Answer 1

Based on the information provided about the deer and wolf populations on the island, here are the answers to questions 2-10:

Question 2: Before the wolves were introduced, how was the deer population changing?

• Response: The deer population was growing rapidly.

Question 3: During the period when there were no wolves, what is the best explanation for WHY the deer population was changing in the way that it was changing?

• Response: The deer didn't have any natural predators, so the deer population went up.

Question 4: If wolves had not been introduced, would the deer population have been able to grow at the same rate forever?

• Response: No, the deer population would have grown quickly for a while but eventually would have been limited somewhat by lack of food and by disease.

Question 5: According to the graph above, in what year were the wolves introduced to the island?

• Response: 2010

Question 6: What is the relationship between the wolves and the deer of the island?

• Response: Wolves are predators and the deer are prey.

Question 7: Which description correctly describes predators and prey?

• Response: Predators hunt, kill, and eat prey.

Question 8: What happened between 2010 and 2015 on the island?

• Response: As the wolf population grew, the wolves ate more deer.

Question 9: What happened between 2016 and 2020 on the island?

• Response: The deer and wolf populations changed slowly and then stabilized.

Question 10: What is the most likely explanation for the way the graph looks for the period from 2018 to 2020?

• Response: The wolf and deer populations were stabilized because the number of predators and the number of prey were well balanced.

These responses summarize how the interactions between the deer and wolves shaped their populations over time.