Trophic Cascades & Keystone Species

How long were the wolves absent from Yellowstone National Park? (a)  

• 1 year
• 5 years
• 10 years
• 70 years

Explain why the population of elk built up.

• There were just a lot of them and so they reproduced quickly.

• There was lots of food for the elk in the park so they reproduced well.

• There was no natural predator to hunt them so they became over populated.

• No one is actually sure why this happened.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

What happened to the vegetation because of the elk population?

• The elk ate it all, They reduced the vegetation to almost nothing, or they devoured it, leaving it bare.

• Nothing at all. the vegetation just grew as normal.

• A drought actually caused the vegetation to die and the elk trampled what was left.

• The elk ate some of it but lots of the vegetation remained.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

When were the wolves reintroduced?

• 1989

• 1886

• 2003

• 1995

Explain how the behavior of the elk changed in response to the wolves.

• They did not change their behavior and therefore most elk died.

• The elk stayed away from the areas the wolves were. As a result, the trees were able to grow again.

• All the elk left the park and did not return.

• The wolves were not able to capture the elk.

Tags

NGSS.MS-LS2-2

NGSS.MS-LS2-4

Why did the height of trees grow dramatically?

• The weather had been much better and the trees grew taller.

• The trees did not grow dramatically. Everything stayed the same.

• The elk were no longer a grazing threat to their growth.

Tags

NGSS.MS-LS1-5

Song birds & migratory birds returned because...

• They come back in the spring every year as normal.

• They came to find shelter in trees, as there were more and taller trees.

• They liked to follow the wolves and eat their left overs/carrion.

• As the weather was much better, they enjoyed the park more.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Beavers returned because...

• There were more trees. They like to build dams and eat trees. They build many habitats and niches for other animals

• They liked the warmer temperatures in the park because of climate change.

• They are carnivores and will eat the wolves.

• They are carnivores and will eat the elk.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4

What is one way the rivers changed because of the wolves?

• trees stabilized the banks so there was less erosion, allowing water to meander

• the rivers became bigger as more water flowed

• less water flowed as the wolves caused a change in the climate

Tags

NGSS.MS-ESS2-2

NGSS.MS-LS2-3

Choose the animals that benefited from the return of the wolves?

• cows living the farms around the park

• lions and tigers living in the park

• elephants that were living in the park

• fish, badger, & beaver living in the park

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4