Lesson 6.3.1b

6.3.1b Succession and sampling of communities Quiz: OCR Biology, Unit 9

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 6.3.1b, Succession and sampling of communities: 20 multiple choice questions for the OCR Biology (H020), Unit 9: Ecosystems, written with Revision Ninja.

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The 20 questions

  1. Where does secondary succession take place?

    • On cooled lava
    • On existing soil
    • On bare rock
    • On sand dunes

  2. Which feature is characteristic of a pioneer species?

    • Slow seed dispersal
    • Large body size
    • High shade requirement
    • High stress tolerance

  3. What is succession called when human activity prevents a natural climax community from forming?

    • Secondary succession
    • Deflected succession
    • Primary succession
    • Climax succession

  4. Which equipment is a square frame used to sample non-motile organisms?

    • A pitfall trap
    • A sweep net
    • A pooter
    • A quadrat

  5. Which line sampling method investigates species distribution across an environmental gradient?

    • A pitfall line
    • A transect
    • A quadrat
    • A point frame

  6. What is the primary advantage of random sampling in an ecosystem survey?

    • Guarantees total coverage
    • Reduces required time
    • Increases species richness
    • Prevents investigator bias

  7. What is the formula for the Lincoln index used in mark-release-recapture?

    • N = (M + n) / m
    • N = m / (M x n)
    • N = M - n + m
    • N = (M x n) / m

  8. In a mark-release-recapture study, 40 animals are marked. A second sample of 50 contains 10 marked animals. What is the estimated population?

    • 400
    • 200
    • 50
    • 20

  9. A 10 x 10 square grid is placed over a quadrat and 37 squares are covered by daisies. What is the percentage cover?

    • 3.7%
    • 63%
    • 100%
    • 37%

  10. Twenty individuals are counted across ten 1 m2 quadrats in a 500 m2 field. Estimate the total population.

    • 500
    • 1000
    • 200
    • 20

  11. The mean count is 6 individuals per 0.5 m2 quadrat in a 200 m2 area. What is the estimated total?

    • 1200
    • 600
    • 200
    • 2400

  12. A species occurs in 15 of 25 quadrats. What is its frequency as a percentage?

    • 15%
    • 25%
    • 60%
    • 40%

  13. Which sampling method best investigates species change from a riverbank to dry land?

    • Interrupted belt transect
    • Random quadrat sampling
    • Pitfall trapping
    • Mark-release-recapture

  14. Which property allows late-stage successional species to replace pioneer species?

    • Superior competitive ability
    • Greater wind dispersal
    • Higher drought tolerance
    • Faster germination rate

  15. Which management practice maintains a grassland plagioclimax by deflecting succession?

    • Pesticide spraying
    • Regular livestock grazing
    • Tree planting
    • Fertiliser application

  16. How can sampling bias be minimised during a field survey of meadow plants?

    • Target visible flowers
    • Generate random coordinates
    • Reduce quadrat count
    • Sample field boundaries

  17. 60 snails are marked and released. A second sample of 80 contains 12 marked snails. What is the estimated population?

    • 48
    • 400
    • 80
    • 12

  18. Why does a low recapture count of marked animals cause Lincoln index estimates to rise?

    • Birth rate increased
    • Marked animals died
    • Unmarked animals died
    • Traps became saturated

  19. Ten quadrats of 0.25 m2 each contain 30 plants in total. The habitat covers 1000 m2. What is the estimated total population?

    • 12000
    • 30000
    • 1200
    • 3000

  20. Why is two years without species change insufficient to confirm a climax community?

    • Monitoring period short
    • Species richness dropped
    • Abiotic conditions varied
    • Pioneers returned quickly

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