Lesson 5.1.1

5.1.1 Ecosystems, communities, populations and biotic and abiotic factors Quiz: Pearson Edexcel Biology A (Salters-Nuffield), Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 5.1.1, Ecosystems, communities, populations and biotic and abiotic factors: 20 multiple choice questions for the Pearson Edexcel Biology A (Salters-Nuffield) (9BI0), Unit 5: On the Wild Side, written with Revision Ninja.

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The 20 questions

  1. In ecology, what is a population?

    • All the organisms living in a habitat including the abiotic factors
    • The non-living conditions of an area such as temperature and light
    • All the different species living together in an area
    • All the organisms of one species living in a given area

  2. Which term describes all the populations of different species living together in one area?

    • Community
    • Ecosystem
    • Niche
    • Habitat

  3. What is the difference between a habitat and an ecosystem?

    • A habitat includes all living things, while an ecosystem is a single species
    • An ecosystem is only the soil, while a habitat is only the living things
    • Habitat is where an organism lives; ecosystem adds the community and abiotic factors
    • A habitat and an ecosystem mean exactly the same thing

  4. Which of these is a biotic factor affecting the distribution of a population?

    • Predation by another species
    • Light intensity at the ground surface
    • Air temperature, a non-living factor
    • Soil pH, which affects nutrient availability

  5. Which is an abiotic factor that can limit the distribution of plants?

    • Herbivory by insects
    • Competition from neighbouring plants
    • Soil moisture content
    • Pathogenic fungal infection

  6. Why are quadrats used in ecology?

    • To grow a single species under controlled conditions
    • To measure the mass of individual organisms exactly
    • To remove predators from a habitat
    • To estimate abundance and distribution of organisms

  7. Why are transects used in a habitat study?

    • To remove competitors from a habitat
    • To count every individual in a habitat exactly
    • To change the temperature of a habitat
    • To show distribution change along a gradient

  8. A student counts an average of 4 daisies per 0.5 m^2 quadrat in a meadow of 2000 m^2. What is the estimated total population of daisies?

    • 16000
    • 4000
    • 2000
    • 8000

  9. Which abiotic factors should be measured in a habitat study?

    • Only the age of the oldest tree in the habitat
    • Only the colour of the organisms present
    • Light intensity, temperature and soil moisture appropriate to the habitat
    • Only the number of species, with no environmental measurements

  10. Which statement best explains why a population's size is limited?

    • Limiting factors such as food, space and predators restrict the numbers that can survive
    • Only abiotic factors limit population size
    • Populations are limited only by the number of individuals that die of old age
    • Populations always grow without limit given enough time

  11. In a community, competition between two species for the same resource is best described as:

    • The breakdown of organic material by decomposers
    • A change in the abiotic conditions of a habitat
    • Organisms reducing a shared resource for each other
    • A mutually beneficial relationship between organisms

  12. A quadrat survey finds more plant species near a river than on a dry hillside. Which abiotic factor is the most likely explanation?

    • Higher soil moisture near the river
    • Greater predation by herbivores on the hillside
    • Greater disease on the riverbank
    • Lower competition from other plants on the riverbank

  13. Why must random sampling be used when placing quadrats in a field study?

    • To avoid bias in choosing where to sample
    • To increase the size of the quadrat
    • To make sure every quadrat contains the same species
    • To prevent the organisms from moving

  14. A transect shows that the abundance of a plant falls steadily with distance from a hedge. What does this suggest?

    • The hedge is causing the plant to become a different species
    • The transect has no statistical value
    • The plant has no relationship with the hedge
    • The hedge creates a gradient such as shade or wind

  15. Which statement about predation as a biotic factor is correct?

    • Predation can reduce prey numbers and affect predators
    • Predation always increases the number of prey organisms
    • Predation has no effect on population size
    • Predation affects only the abiotic environment

  16. An ecologist wants to know how the distribution of snails changes in a stream. Which method is most suitable?

    • A transect from the bank with quadrats at intervals
    • A single quadrat placed on the bank only
    • Measuring the mass of one snail in a laboratory
    • Counting snails in one pond on a single day only

  17. Why is the term ecosystem used in ecology?

    • It describes a single species and its genes
    • It describes only the temperature of the water
    • The living community plus its non-living environment
    • It describes only the dead organic matter in a habitat

  18. A student says the community of a pond includes its water and light. What is the best evaluation?

    • Incorrect, because the community contains only fish
    • Incorrect, since water and light are abiotic factors
    • Correct, because light and water are organisms in the community
    • Correct, because the community is defined by its abiotic factors only

  19. A population of mice in a field declines after a fox population increases. Which is the most likely cause?

    • A rise in soil pH
    • Increased light intensity in the field
    • Lower air pressure affecting the mice
    • Increased predation by foxes on the mice

  20. In a quadrat survey, a student finds 12 buttercups in each of 10 quadrats of 0.25 m^2 area. What is the estimated density of buttercups per m^2?

    • 12
    • 120
    • 48
    • 2.5

All Pearson Edexcel Biology A (Salters-Nuffield) quizzes