Changes in Ecosystems

How is secondary succession different from primary succession?

• A. Secondary succession occurs after a disturbance in an area that was previously uninhabited.

• B. Secondary succession occurs after a disturbance in an area in which the soil has remained intact.

• C. Secondary succession occurs over a longer period of time than primary succession.

• D. Secondary succession occurs when animals are introduced to an area that had only plants.

How do pioneer species make ecological succession possible on an island formed from volcanic eruptions?

• A. They use chemicals to produce food.

• B. They establish homes in which animals can live.

• C. They break down rock into soil in which plants can grow.

• D. They adjust the climate by altering the average temperature in a region.

Which statement best describes ecosystems?

• They can never change once they are established.

• They constantly change in different ways over time.

• Ecosystems always revert back to their original state.

• Each ecosystem can exist for only a specific length of time.

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NGSS.MS-LS2-2

NGSS.MS-LS2-4

Which term best describes the number and variety of organisms in a given area during a specific period of time?

• carrying capacity

• biodiversity

• succession

• eutrophication

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NGSS.MS-LS2-5

The diagram shows changes to a pond ecosystem over time. Through which of the following processes are plant communities taking over the ecosystem?

• acidification

• primary succession

• climate disturbance

• natural eutrophication

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NGSS.MS-LS2-4

What are some climate disturbances?

• hurricane

• volcano

• thunderstorm

• fog

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NGSS.MS-ESS3-2

Secondary succession happens to areas that have been disturbed but still have what?

• sunlight

• water

• lichen

• soil

What helps an ecosystem stay stable until the ecosystem is disturbed?

• climax species

• biodiversity

• pioneer species

• eutrophication

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NGSS.MS-LS2-3

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By the time climax species are established, the resources in the area support many different kinds of organisms, which is?

• eutrophication

• biodiversity

• secondary succession

• primary succession

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NGSS.MS-LS2-5

After a forest fire the pioneer species would be

• lichens and moss

• grasses and weeds

• shrubs and bushes

• pine trees

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NGSS.MS-LS2-4