Impact of Wolves in Yellowstone

Question

Wolves are an important predator in Yellowstone National Park. When wolves were removed, the elk population grew too large. The elk ate too many trees and shrubs. The lack of shrubs and trees meant the bird population went down, as they needed the shrubs and trees for their habitat.

Later, when the wolves returned and were able to decrease the elk population, the numbers of trees (like the cottonwood tree) and shrubs were able to increase. When the trees and shrubs increased, the bird populations grew. The birds and the trees help each other. The birds help scatter seeds for new trees, while the trees provide shelter for the birds.

Question 1
Consider the data shown in the graph below.

7. Thinking about the graph below, what argument can be made regarding the relationship between the changes to the songbird habitat and the population of songbirds?

(1 point)
Responses

When habitat availability is decreased, songbird population goes up.
When habitat availability is decreased, songbird population goes up.

Habitat availability and songbird population are not related.
Habitat availability and songbird population are not related.

When habitat availability is increased, songbird population goes down.
When habitat availability is increased, songbird population goes down.

When habitat availability is increased, songbird population goes up.
When habitat availability is increased, songbird population goes up.
Question 2
8. Use the choices from the drop down menus to fill in each blank.(4 points)
There is a
relationship between trees and birds. The trees
the birds, and the birds
the trees. This means the relationship is an example of
.

Answer 1

Question 1:

The argument that can be made regarding the relationship between the changes to the songbird habitat and the population of songbirds is:

When habitat availability is increased, songbird population goes up.

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Question 2:

There is a mutualistic relationship between trees and birds. The trees provide shelter for the birds, and the birds help scatter seeds for the trees. This means the relationship is an example of mutualism.