Unit 3: Learning Set 3 - Test Review

Describe what is happening to the fox population between lines A and B. Why is this happening?

• The fox population increases at A because they have more food available since the rabbit population has been increasing.

• The fox population decreases at A because they have less food available since the rabbit population has been increasing.

• The fox population decreases at A because they have more food available since the rabbit population has been increasing.

• The fox population increases at A because they have less food available since the rabbit population has been decreasing.

Describe what is happening to the rabbit population between lines A and B. Why is that happening? Choose all that apply.

• The rabbit population increases at B because the fox population is increasing, meaning there are more predators for the rabbits.

• The rabbit population decreases at B because the fox population is decreasing, meaning there are more predators for the rabbits.

• The rabbit population decreases at B because the fox population is increasing, meaning there are more predators for the rabbits.

• The rabbit population decreases at B because the grass is low, meaning there is less food for rabbits (and increased competition).

Describe what is happening to each of the populations between lines B and C.

• The grass population decreases when the rabbit population is low. This occurs because the rabbit population is eating the grass.

• The grass population increases when the rabbit population is high. This occurs because the rabbit population is eating the grass.

• The rabbit population causes the grass population to increase at first but after a while, the rabbit population kills the grass or eats it all.

• The grass population decreases when the rabbit population is high. This occurs because the rabbit population is eating the grass.

Pick one pattern you saw in the model and describe in general what you saw. Choose all that apply.

• Populations often interact with one another however, it does not change the overall population numbers.

• Populations can affect other populations in competitive relationships.

• Populations don’t affect other populations much.

• Populations can affect other populations in predator/prey relationships.

Provide the evidence and reasoning to support the claim that the invasive species eats the grass. Choose all that apply. Claim: The invasive species eats the grass. Evidence and Reasoning:

• The evidence is that the invader survived without foxes or rabbits.

• The evidence is that when the invader enters the ecosystem, the grass and rabbits increase.

• The evidence is that when the invader enters the ecosystem, the grass and rabbits decrease.

• The rabbits competed with the invader for grass, which caused the rabbit population to decrease. This meant the foxes decreased because they had less food (rabbits).

• The rabbits competed with the invader for grass, which caused the rabbit population to increase. This meant the foxes decreased because they had less food (rabbits).

Use the graph to describe the population trends for the sea lamprey from 1944-1952.

• The sea lamprey population is stable.

• There is not enough data to identify a trend.

• The sea lamprey population is increasing.

• The sea lamprey population is decreasing.

Describe the population trends for the trout from 1961-1970.

• The trout population is stable.

• The trout population is decreasing.

• The trout population is increasing.

• There is not enough data to identify a trend.

Is the sea lamprey the only thing affecting the trout?

• No

• Yes

If lack of food is the only reason trout are declining, what would a graph of the trout’s food show?

• The prey would stay stable.

• The numbers would go back to the way they were several years before.

• The prey would decrease.

• The prey would increase.

What is the overall trend for the chub from 1940–1960?

• It is increasing.

• It is always the opposite of Lake Trout.

• It is decreasing.

• It is stable