Topic 9 ecosystems higher

Questions
Q1.
A student was investigating the populations of organisms in a garden.
Figure 1 shows the estimates of the number and biomass of some of the organisms in the garden.

(i) Calculate the biomass of the population of earthworms in the garden.
(1)

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(ii) Hedgehogs eat slugs and earthworms.
Slug pellets were used to kill the slugs.
Explain how killing the slugs would affect the population of earthworms in this garden.
(2)
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(iii) Describe a method that could be used to estimate the population of slugs in the garden.
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(Total for question = 6 marks)

Q2.
Figure 6 shows the global movement of carbon into or out of the atmosphere.

Calculate the net mass of carbon added to the atmosphere each year.
(2)

………………………………………………….. gigatonnes

(Total for question = 2 marks)

Q3.
Figure 1 shows an area of woodland with some small plants growing in the ground between the trees.

The scientist selects an area near the edge of the woodland where many stinging nettles are growing.
This area is partly shaded by the trees.
Describe how the scientist should use a belt transect to investigate how light intensity affects the growth
of stinging nettles.
(3)
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(Total for question = 3 marks)

Q4.

Leguminous plants have nodules on their roots that have colonies of nitrogen-fixing bacteria.
Clover is a leguminous plant.
Describe how a quadrat could be used to sample the population of clover in a 500m2 field.
(3)
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(Total for question = 3 marks)

Q5.
Figure 1 shows an area of woodland with some small plants growing in the ground between the trees.

A scientist recorded the mean light intensity and the mean number of small plants per m2 for six 25 m2
areas of the woodland.

Figure 2 shows the results.

(i) Explain the effect of light intensity on the number of small plants per m2.
(2)
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(ii) State one variable the scientist should have controlled to make sure the light intensity measurements
could be compared.
(1)
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(Total for question = 3 marks)

Q6.
Cowslips are flowering plants.
Each cowslip stem can produce different numbers of flowers.
The graphs show the number of flowers on 20 stems of cowslip growing in open grassland and 20 stems
of cowslip growing in woodland.

(i) In the open grassland, 60% of cowslips have stems with five or more flowers.
Use the information from the graph to calculate the percentage of cowslips in the woodland that have
stems with five or more flowers.
(2)

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(ii) Suggest reasons why there are more stems with five or more flowers in the open grassland.
(2)
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Q7.
A student investigated the effect of nitrate ion concentration on plant growth. She placed barley seedlings
in three test tubes containing different concentrations of nitrate fertiliser.
Test tube 1 contained distilled water with 1 pellet of nitrate fertiliser.
Test tube 2 contained distilled water with 2 pellets of nitrate fertiliser.
Test tube 3 contained distilled water with 3 pellets of nitrate fertiliser.
After 7 days, the lengths of the seedlings were measured.
Figure 13 shows an example of the apparatus used.

Figure 13
(i) Describe a control for this investigation.
(2)
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(ii) The nitrate fertiliser contains the chemical compound potassium nitrate. The hazard symbol on the
bag of potassium nitrate fertiliser is shown in Figure 14.

Figure 14
Which hazard does this symbol represent?
(1)
A
B
C
D

flammable
oxidising
corrosive
explosive

(iii) Give a method, other than measuring the change in length, that would show the growth of the
seedlings.
(1)
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(Total for question = 4 marks)

Q8.
Photosynthesis

The diagram shows a plant cell.

(a) Complete the sentence by putting a cross (

) in the box next to your answer.

This plant cell is a
(1)
A
B
C
D

xylem vessel
phloem vessel
root hair cell
leaf palisade cell

(b) Explain how water moves from cell to cell in a leaf.
(2)
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(c) Some small plants can grow on the bark of trees.
The distribution of two plant species, species A and species B, growing on the north and south side of
a tree was investigated.
The results are shown in the table.

(i) Draw a bar chart to illustrate the data in this table.
(2)

(ii) Which piece of equipment would be used to measure the distribution of plants on the bark of the
tree?
Place a cross ( ) in the box next to your answer.
(1)
A
a pooter
B
a sweep net
C
a pitfall trap
D
a quadrat

(iii) Suggest reasons for the distribution of species B on the north and south sides of the tree.
(2)
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(Total for question = 8 marks)

Mark Scheme
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