Year 11

1. The table describes stages in the water cycle.

Complete the table by naming or describing each stage.
The first one has been done for you.
(3)

(a) Describe the biological consequences of pollution of water by sewage.

(4)
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 (Total for question = 7 marks)

2 Scientists can show the relationships between organisms in a variety of ways.

This food chain shows the energy content at each trophic level.
plants rabbits fox fleas
8450 J 780 J 90 J 4J

(a) (i) Calculate the percentage of energy that is transferred from the rabbits to the fox.
(2)

answer = ........................................................................... %

(ii) State two ways in which energy can be lost between the trophic levels of the rabbit
and the fox.
(2)

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(b) Suggest how a farmer rearing chickens could limit energy loss from the chickens.
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(c) (i) Complete the sentence by putting a cross ( ) in the box next to your answer.
Fleas are parasites that feed on foxes.

Another example of parasites is

(1) A cleaner fish

B lichens

C mistletoe

D ox peckers

(ii) Peas and beans are known as legumes.

They form a mutualistic relationship with the bacteria in their roots.
Explain the importance of this mutualistic relationship to the legumes.
(3)
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(Total for Question 2 = 10 marks)

3 The diagram shows the nitrogen cycle. Different stages have been numbered 1 to 8.

(a) The table lists the stages involved in the nitrogen cycle.

Complete the table by giving the correct number, or numbers, corresponding to each stage.

The first one has been done for you.

(4)
 (b) Explain how nitrates are absorbed into plants at stage 8.
(3)

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(Total for question = 7 marks)

4. The food chain shows the energy transferred between organisms.

7760 kJ 620 kJ 50 kJ
oak tree ĺ caterpillars ĺ blue tits ĺ sparrow hawk
 (a) (i) The oak tree is the producer in the food chain.

Complete the sentence by putting a cross ( ) in the box next to your answer.

The oak tree obtains energy

(1)

A autotrophically

B heterotrophically

C parasitically

D saprophytically

(ii) The energy available in the oak tree that could be transferred to the caterpillars
was 97 000.

Calculate the percentage loss of energy between the oak tree and the
caterpillars.
(3)

................................................. %

(iii) Suggest how energy is lost between trophic levels in this food chain.
(2)
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*(b) The survival of some organisms may depend on mutualism.

Explain, using three examples, how some organisms benefit from mutualism.
(6)
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(Total for Question 4 = 12 marks)

5. Read the passage below. Use the information in the passage and your own knowledge to
answer the questions that follow.

Red and Grey Squirrels

 (Photographer: Matti Parkkonen)

Red squirrels live in pine tree habitats in the United Kingdom (UK) where their
main predators are birds of prey such as the goshawk. The squirrels mainly eat
pine cone seeds. This food is plentiful in the autumn and helps the squirrels
increase their body mass. Having a larger body mass helps red squirrels to
survive the cold winter conditions. It also means that breeding females are in
good condition to produce young in the spring.

Red squirrels were common in the UK until a different species, the grey squirrel,
was introduced from America in 1876. The two species struggled to exist in the
same woodland habitat and it is the red squirrel population that
10 is decreasing. There are estimated to be only 140000 red squirrels left in
the UK, and 2.5 million grey squirrels. The spread of the grey squirrel has
been rapid, and in some areas native red squirrels are no longer seen.

The grey squirrel outcompetes the red squirrel and there is some evidence that
it is also more resistant to disease. The increase in the number of grey
15 squirrels in the UK is having a harmful effect on other native communities
where the plants and animals are poorly adapted to withstand their presence.
The grey squirrels are causing significant harm to woodland habitats, and
recent scientific studies have reported that they are having a serious effect on
the number of native woodland birds.

20
The Forestry Commission is an organisation in the UK trying to develop a
long-term conservation strategy to save the red squirrel from extinction. It
is hoped that this work will help to restore the UK’s native biodiversity.
(a) Name a secondary consumer in a food chain containing red squirrels.
(1)
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(b) Suggest how a larger body mass helps squirrels survive the cold winter (lines
4 and 5).
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(c) Suggest two reasons why it is an advantage for red squirrels to produce young in the
spring (line 6).
(2)

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(d) (i) What is meant by the term habitat?

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(ii) What is meant by the term population?

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(e) Use the data in the passage to calculate the percentage of all the squirrels in the UK
that are red. Show your working.
(2)

percentage .............................................................. %

(f) Give two possible reasons why grey squirrels are increasing in number compared to
red squirrels.
(2)
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(g) Grey squirrels have a greater effect on the number of woodland birds than red
squirrels (lines 17 to 19).

Suggest how scientists could collect data to support this hypothesis.

(3)
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(h) Suggest two methods the Forestry Commission might use to save the red squirrel from
extinction (line 21).
(2)

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(Total for Question = 16 marks)

6. Explain the methods used to produce large numbers of fish in a fish farm.
(6)
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(Total for Question = 6 marks)

7. Caterpillars feed on hawthorn bushes. The caterpillars are eaten by small birds such as the
dunnock. The dunnocks are preyed on by a larger carnivorous bird, the sparrow hawk.
This data was collected from a hedgerow.

(a) Use the information in the table to draw an accurate pyramid of numbers for this data
on the grid below.
(4)

(b) Describe how a pyramid of biomass from the same data would differ from the pyramid
of numbers.
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(c) Explain why not all the energy in a producer passes to the primary consumer.
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(d) Some farmers are removing hedges in order to increase the size of their fields.
This means that the number of hawthorn bushes is decreasing.
Suggest how removing hawthorn bushes will affect the size of the dunnock population.
(2)

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(Total for question = 10 marks)

8.

(a) (i) Use the information in this food chain to complete the diagram.
(3)

(ii) Name one type of organism that is a decomposer.

(1)
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(b) Decomposition is a stage in the carbon cycle. The other stages are respiration,
photosynthesis and combustion.

How many of these four stages add carbon dioxide to the air?
(1)
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(Total for question = 5 marks)