Exam practice

Exam questions

Write your answer. Then open the mark scheme and tick each point you made.

  1. Question 1 of 101 mark

    State what an arrow in a food chain shows.

    Mark scheme
    • The direction in which energy is transferred, from the food to the living thing that eats it (accept: “is eaten by”)
  2. Question 2 of 102 marks

    Here is a food chain from a rocky shore: seaweed → limpet → crab → gull. Name (a) the producer and (b) the secondary consumer.

    Mark scheme
    • (a) Seaweed
    • (b) Crab
  3. Question 3 of 104 marks

    The diagram shows a food web from an oak wood.Oak treeCaterpillarAphidBlue titLadybirdSparrowhawk(a) Write down one food chain from this web that has four living things in it.
    (b) Name one animal in the web that is both a predator and prey.
    (c) A disease kills most of the ladybirds. Predict what happens to the number of aphids, and explain why.

    Mark scheme
    • (a) Oak tree → caterpillar → blue tit → sparrowhawk, or oak tree → aphid → blue tit → sparrowhawk (the arrows must point this way)
    • (b) Blue tit
    • (c) The number of aphids rises
    • (c) Because fewer of them are eaten by ladybirds
  4. Question 4 of 102 marks

    Describe what decomposers do in an ecosystem.

    Mark scheme
    • They break down dead plants and animals (accept: and waste)
    • This returns nutrients to the soil, so that plants can use them again (accept: recycles nutrients)
  5. Question 5 of 102 marks

    Rabbit numbers in a wood go up. A year later, fox numbers go up too. Explain why.

    Mark scheme
    • The foxes have more food (accept: more prey)
    • So more foxes survive and breed (accept: more cubs survive)
  6. Question 6 of 102 marks

    Grey squirrels were brought to Britain from North America. They eat the same food as red squirrels. Explain why the number of red squirrels fell.

    Mark scheme
    • The two species compete for food
    • So there was less food left for the red squirrels (accept: grey squirrels also carry a disease that kills red squirrels)
  7. Question 7 of 103 marks

    Explain why a fall in the number of bees could mean that farmers grow less food.

    Mark scheme
    • Bees pollinate the flowers of many food crops (accept an example, such as apples)
    • Flowers that are not pollinated do not make fruit or seeds
    • So the harvest is smaller (accept: there is less of these foods, or they cost more)
  8. Question 8 of 101 mark

    Give one example of a living thing changing its environment.

    Mark scheme
    • Any one: a beaver builds a dam that makes a pond; a tree shades the ground beneath it; earthworms mix air into the soil (accept any correct example)
  9. Question 9 of 102 marks

    A long, dry summer dries out a pond. Describe what is likely to happen to the population of frogs that breed there, and explain why.

    Mark scheme
    • The population falls (accept: the frogs die or move away)
    • Frogs need water to breed (accept: their eggs and tadpoles need water, or their habitat is lost)
  10. Question 10 of 103 marks

    A long-lasting pesticide is washed into a lake. Explain why a heron at the top of the food chain ends up with far more of it in its body than a small fish.

    Mark scheme
    • The pesticide is not broken down or passed out, so it stays in the body (accept: it is taken in faster than it is lost)
    • Each animal eats many of the living things below it in the chain, and takes in the pesticide from all of them
    • So the amount builds up at each step and is greatest in the top predator (accept: bioaccumulation)
These questions and their mark scheme (PDF)