Keystone Species

What is the definition of a keystone species?

• A species that has a large impact on its habitat

• A species that is at the top of the food chain

• A species that is endangered

• A species that is found in Yellowstone National Park

What happened to the grey wolf population in Yellowstone National Park in the early 1930s?

• Their numbers increased significantly

• Their numbers remained stable

• Their numbers dropped to zero

• Their numbers doubled

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How did the absence of wolves in Yellowstone National Park affect the behavior of elk?

• Elk became more cautious and nomadic

• Elk became less cautious and settled in one place

• Elk started hunting wolves

• Elk migrated to a different habitat

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What happened to the trees and plants in Yellowstone National Park when the elk population increased?

• The trees and plants flourished

• The trees and plants declined

• The trees and plants remained the same

• The trees and plants migrated to a different area

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NGSS.MS-LS2-1

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What is the role of beavers in the ecosystem?

• They prey on elk

• They build dams and create habitats

• They eat plants and trees

• They control the wolf population

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What happened to the willows and beaver colonies in Yellowstone National Park after the reintroduction of wolves?

• They declined

• They remained the same

• They increased

• They migrated to a different area

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What is the impact of elephants on their environment?

• They help spread seeds to new places

• They eat all the plants and trees

• They build dams and prevent floods

• They control the population of other animals

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What happens to the forest when African Forest elephants are absent?

• The forest becomes more diverse

• The forest becomes dominated by a single species of tree

• The forest remains the same

• The forest disappears

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What is the role of parrotfish in coral reefs?

• They eat algae and help keep the reef healthy

• They build coral reefs

• They prey on other fish

• They control the temperature of the water

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What happens to coral reefs when parrotfish are heavily fished?

• The reefs become healthier

• The reefs become more diverse

• The reefs become dominated by macroalgae

• The reefs disappear

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4