Yellowstone Wolves

Beavers are excellent builders that use trees to create dams in the water. Dams are made of logs, sticks, branches, and then sealed with mud. Dams help to slow and redirect the flow of water. Beavers are herbivores that eat the bark, stems, leaves, and twigs of trees along with other aquatic plants. Beavers have many predators, including coyotes, bears, foxes, and wolves. The graph shows the beaver colony populations in Yellowstone after the reintroduction of wolves.

Which statement BEST describes the beaver population?

• The beaver population increased because they had fewer predators. 

• The beaver population decreased because they had less available food.

• The beaver population increased because they had more available trees. 

• The beaver population decreased because they had more competition for resources. 

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4

Which BEST predicts how another loss of wolves from Yellowstone would affect interactions between bears and ravens?

• Bears would eat more ravens. 

• Bears would become prey to more ravens. 

• Bears and ravens would have increased competition.

• Bears and ravens would become dependent on each other. 

Tags

NGSS.MS-LS2-2

NGSS.MS-LS2-4

Bison and elk both compete for ​ (a)   .  An increase in the elk population would ​ (b)   the resources available to bison, ​ (c)   their populations. 

• grasses

• shrubs

• decrease

• increase

• decreasing

• increasing

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

The data shows the simplified diet of a bear in Yellowstone.

How were bears MOST LIKELY affected by the loss of wolves in Yellowstone?

• They would have had less food year-round, especially after hibernation in March.

• They would have had less food year-round, especially after hibernation in March.

• They would have had more food year-round, especially before hibernation in November.

• They would have had less food year-round, especially before hibernation in November.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4

What would MOST LIKELY have happened to the elk population if wolves had not been reintroduced into the park?

• The elk population would have increased indefinitely because there would have been less competition for resources.

• The elk population would have begun to decrease because there would have been limited chances for reproduction.

• The elk population would have increased indefinitely because there would not be any predators to reduce them.

• The elk population would have eventually begun to decrease because their resources would become limited.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4

Which TWO populations of organisms most benefited from the return of the aspens and the willows?

• bison

• birds

• butterflies

• beavers

• wolves

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Which claim is BEST supported by the data in the passage?  

• 
  Between 1995 and 1998, a decrease in the elk population caused an increase in the growth of the Booth willow population.

• Between 1995 and 1998, a decrease in the elk population caused a decrease in the growth of the Geyer willow population.

• 
  Between 1995 and 1998, an increase in the elk population caused a decrease in the growth of the Aspen population in the uplands. 

• Between 1995 and 1998, an increase in the elk population caused an increase in the growth of the Aspen population in riparian areas. 

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-2

NGSS.MS-LS2-4