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7th grade How an ecosystem rebuilds after a change worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

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How an ecosystem rebuilds after a change

Grade 7 Science Worksheet - Building Confidence

NameDate

Circle the best answer.

  1. A volcano builds a brand-new island of bare lava rock with no soil. Which kind of succession starts there, Ari?

    • Neither: plants can't grow on rock
    • Secondary succession
    • Primary succession
    • A climax community

  2. A farm field is left alone. Its soil is still there, and weeds sprout each spring. Which kind of succession is this, Bo?

    • A climax community
    • Primary succession
    • Secondary succession
    • Neither: the field has no plants

  3. A fire clears a forest, but the soil stays, with seeds in it. Which kind of succession follows, Esme?

    • Bare-rock succession
    • Neither: the forest can't grow back
    • Primary succession
    • Secondary succession

  4. New lava has cooled into bare rock. Which living things usually settle there first, Jun?

    • Tall trees
    • Plants can't grow on rock
    • Shrubs
    • Lichens and mosses

  5. On new lava, which plant type usually shows up last, Kira?

    • Lichens and mosses
    • Trees
    • Ferns in the cracks
    • Grasses

  7. At 80 years after the lava flow, which plant type covers the most ground, Milo?

    • Trees
    • Lichens and mosses
    • Grasses
    • Shrubs

  8. Between 80 and 200 years after the lava flow, what happens to the grasses line, Pia?

    Use the picture in question 6.

    • It rises from 0% to 60%
    • It stays at 40%
    • It falls from 40% to 10%
    • It rises from 10% to 40%

  9. Lichens and mosses grow on bare lava for many years. How does that help the plants that come later, Ren?

    • They make the rock harder
    • They turn into trees
    • They help build soil from the rock
    • They don't help; trees come first

  10. On a lava island, why do grasses spread after the pioneers instead of before them, Tala?

    • By then there is some soil
    • Grasses need bare rock
    • The lava gets hotter
    • Grasses grow first, before lichens

  11. Bits of moss and lichen break down on the rock each year. What do they add to the new soil, Zee?

    • Salt water
    • Bare rock
    • Plant matter with nutrients
    • More lava
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7th grade How an ecosystem rebuilds after a change worksheet – printable
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About this worksheet

How an ecosystem rebuilds after a change. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can tell primary succession (bare rock, no soil) from secondary succession (soil left behind).
  • I can put the stages in order and say how pioneers such as lichens and mosses help later plants.
  • I can read a succession graph by plant type and explain why a line rises or falls.

Standard: supports MS-LS2-4

Words to know

succession: The order in which plant types arrive and replace each other after a change

primary succession: Succession on new bare rock, such as lava, with no soil yet

secondary succession: Succession where a change cleared plants but the soil stayed

pioneer species: The first hardy living things on bare rock, like lichens and mosses

climax community: The steady community at the end, lasting until the next big change

Common mistakes

Your child mixed up primary and secondary succession. Primary starts on bare rock with no soil; secondary starts where the soil is left.

Your child put bigger plants too early. Small, hardy plants come first, and shrubs and trees take over later as the soil builds up.

Your child read the wrong line or the wrong year on a graph. Point to the line's label, then the year, then read across to the value.

Questions parents ask

What is the most common mistake with how an ecosystem rebuilds after a change?

Your child mixed up primary and secondary succession. Primary starts on bare rock with no soil; secondary starts where the soil is left.

Are these 7th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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