GCSE Biology (AQA) chapter 7: Ecology MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

64 exam-style questions on Ecology, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

64 questions · 5 topics · 10 per test

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What chapter 7 covers

Ten Ecology questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. A student wants to show how the distribution of a plant changes gradually from under a tree into an open field. Which method is most suitable?

  1. A
    quadrats placed at random across both areas, then comparing the two totals
  2. B
    counting all the plants in the field, then all the plants under the tree
  3. C
    a single quadrat under the tree and a single quadrat in the open
  4. D
    quadrats at regular intervals along a transect from the tree
Show answer

Answer: D. A transect line with quadrats at regular intervals shows how distribution changes across a gradient, such as from shade to light.

2. Which process removes carbon dioxide from the atmosphere in the carbon cycle?

  1. A
    respiration in plants and animals
  2. B
    photosynthesis in plants and algae
  3. C
    combustion of fuels such as wood and coal
  4. D
    decay of dead material by microorganisms
Show answer

Answer: B. Green plants and algae take in carbon dioxide for photosynthesis. Respiration, combustion and decay return carbon dioxide to the air.

3. How is mycoprotein produced?

  1. A
    by growing genetically modified bacteria that make human insulin in a fermenter
  2. B
    by modifying rice plants so that their grains contain extra vitamin A
  3. C
    by growing the fungus Fusarium on glucose syrup in a fermenter
  4. D
    by fermenting milk with bacteria to make a protein-rich yoghurt
Show answer

Answer: C. The fungus Fusarium is grown in large vessels on glucose syrup with oxygen; the biomass is harvested and purified to make mycoprotein.

4. A survey finds 12 species in pond X and 4 species in pond Y, with the same total number of organisms in each. Which statement is correct?

  1. A
    pond X has greater biodiversity and is more likely to stay stable if one species is lost
  2. B
    pond Y has greater biodiversity, because each of its species has more individuals
  3. C
    the ponds have the same biodiversity, because they have the same number of organisms
  4. D
    pond Y is more stable, because its species have less competition from other species
Show answer

Answer: A. Biodiversity is the variety of species, not the number of individuals. More species means the loss of one has less effect, because others can take its place.

5. Why does each bar in a pyramid of biomass get smaller towards the top?

  1. A
    animals at higher levels are larger than plants, so fewer of them are needed
  2. B
    there are more predators than prey, so the higher levels use up more biomass
  3. C
    only some biomass passes on to the next level
  4. D
    producers have the least biomass, because plants are eaten before they can grow
Show answer

Answer: C. Much biomass is lost at each level (in respiration, waste and parts not eaten), so less is available for the next level.

6. Which is an example of modern biotechnology in food production?

  1. A
    a crop that has been genetically modified to resist damage by insect pests
  2. B
    crop rotation, which restores nitrogen compounds to the soil
  3. C
    feeding animals a high-protein diet so that they gain mass
  4. D
    using larger mesh nets to protect young fish stocks
Show answer

Answer: A. Biotechnology uses organisms to make useful products: GM bacteria make insulin, Fusarium makes mycoprotein, and GM crops can give higher yields or resist pests.

7. Two male lions fight over a group of females and the grassland where they hunt. Which resources are they competing for?

  1. A
    mates, and a territory in which to hunt and feed
  2. B
    light and mineral ions that are absorbed from the soil
  3. C
    carbon dioxide and water for use in photosynthesis
  4. D
    space and chlorophyll for the growth of leaves
Show answer

Answer: A. Animals compete for food, mates and territory.

8. In one year, the plants in a forest take in 900 units of carbon by photosynthesis. Respiration by plants and animals releases 600 units, and decomposers release a further 200 units. What is the net effect of the forest on the carbon in the atmosphere?

  1. A
    it decreases by 100 units
  2. B
    it increases by 100 units
  3. C
    it decreases by 300 units
  4. D
    it increases by 800 units
Show answer

Answer: A. Carbon removed = 900. Carbon released = 600 + 200 = 800. Net change in the atmosphere = 800 − 900 = −100, a decrease of 100 units.

9. A pyramid of biomass is drawn with a scale of 1 cm = 100 g/m2. The primary consumers have a biomass of 90 g/m2. What is the width of their bar?

  1. A
    9 cm
  2. B
    0.9 cm
  3. C
    0.09 cm
  4. D
    1.1 cm
Show answer

Answer: B. Width = 90 ÷ 100 = 0.9 cm. The bar for a level with less biomass is narrower than the bar below it.

10. How is the carbon in dead leaves returned to the atmosphere?

  1. A
    the leaves photosynthesise, releasing the carbon into the air as they decay
  2. B
    the carbon evaporates directly from the dead leaves as they dry out
  3. C
    rain washes the carbon out of the leaves into the air above the soil
  4. D
    decomposers respire and release carbon dioxide into the air as they feed
Show answer

Answer: D. Microorganisms feeding on dead material respire, releasing carbon dioxide back into the atmosphere and mineral ions into the soil.

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Ways to practise this chapter

Ecology: questions students ask

How many Ecology MCQs are there?

64, each with the answer and a short explanation, across 5 topics: 4.7.1 Adaptations, interdependence and competition, 4.7.2 Organisation of an ecosystem, 4.7.3 Biodiversity and the effect of human interaction on ecosystems, 4.7.4 Trophic levels in an ecosystem, 4.7.5 Food production. Every chapter test draws ten of them, so you can take it many times.

Is the GCSE Biology (AQA) chapter 7 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

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