AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

Q1.
Scientists are very concerned about the changes in concentration of carbon
dioxide in the Earth’s atmosphere.

The graph below shows the concentration of carbon dioxide in the atmosphere
between 1988 and 2014.

(a) Describe two patterns shown in the graph above.

Use data from the graph above in your answer.

1 _________________________________________________________

___________________________________________________________

___________________________________________________________

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2 _________________________________________________________

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(4)

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

(b) Give two human activities that affect the concentration of carbon dioxide in
the atmosphere.

1 _________________________________________________________

___________________________________________________________

2 _________________________________________________________

___________________________________________________________
(2)

(c) The trend shown in the graph above may continue for many years.

Explain what effect the changing concentration of carbon dioxide in the

atmosphere could have on living organisms.

___________________________________________________________

___________________________________________________________

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(4)
(Total 10 marks)

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

Q2.
The graph below shows the human population from 1600 to 2010.

In 1900 the human population was 1.6 billion.

(a) Calculate how many times greater the human population was in the year
2000 compared with the year 1900.

___________________________________________________________

___________________________________________________________

___________________________________________________________

Number of times greater = _______________

(2)

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

(b) In 1950 the human population was 2.5 billion.

Calculate the mean annual increase in the human population between

1900 and 1950.

___________________________________________________________

___________________________________________________________

___________________________________________________________

Mean annual increase = _______________ billion per year

(2)

(c) Predict the human population in 2050 if the current rate of population
increase continues.

You should draw an extrapolation line on the graph above.

___________________________________________________________

___________________________________________________________

___________________________________________________________

Predicted human population = _______________

(2)

(d) The increasing human population has caused a decline in fish stocks.

Describe how fishing quotas can help to return fish stocks to a sustainable
level.

___________________________________________________________

___________________________________________________________

___________________________________________________________

___________________________________________________________
(2)

(e) Farming techniques have changed in recent years.

Describe:
• why more land is being used for farming
• how increased farming has decreased biodiversity.

___________________________________________________________

___________________________________________________________

___________________________________________________________

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

___________________________________________________________

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(6)

(f) Genetic modification of crop plants can help meet the demands of the
increasing human population.

Golden rice is a genetically modified (GM) crop.

What is the advantage of golden rice compared with non-GM rice?

Tick (✓) one box.

Golden rice contains protein-rich mycoprotein

Golden rice has improved nutritional value

Golden rice produces human insulin

(1)

(g) Suggest one reason why some people are concerned about the use of
golden rice.

___________________________________________________________

___________________________________________________________
(1)
(Total 16 marks)

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

Q3.
Figure 1 shows a flightless bird called the dodo (Raphus cucullatus).

Figure 1

The dodo:

• was 1 m tall

• had a mass of 20 kg

• lived in rainforests on a tropical island

• ate fruits

• made its nest on the ground.

A female dodo laid only one egg each year.

Humans arrived on the island in the year 1507. By 1681 the dodo was extinct.

(a) What is the genus of the dodo?

Tick (✓) one box.

Animal

Bird

Raphus

(1)

(b) Before the arrival of humans, there were no other large animals living on
the island.

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

Suggest two reasons why the dodo became extinct soon after the arrival of
humans.

1 _________________________________________________________

___________________________________________________________

2 _________________________________________________________

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(2)

Today, humans are cutting down large areas of tropical rainforests.

(c) Suggest one use of the land after the trees have been removed.

___________________________________________________________

___________________________________________________________
(1)

(d) Why does the removal of trees cause an increase in carbon dioxide in the
atmosphere?

Tick (✓) two boxes.

There are fewer animals.

There is less photosynthesis.

There is less respiration.

The soil dries out.

The trees are burned.

(2)

(e) What effect would an increase in carbon dioxide in the atmosphere have on
global air temperature?

Tick (✓) one box.

Decrease

Increase

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

Stay the same

(1)

‘Sustainable forestry’ reduces the harmful effects of cutting down trees on the
environment.

Figure 2 shows a method of ‘sustainable forestry’.

Numbers 1–9 show different parts of a rainforest.

Figure 2

The trees are cut down in the sequence 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9

• The trees are cut down in only one area at any one time.

• It takes 30 years to cut down the trees in each area.

• The trees in the ‘Old growth’ area are never cut down.

(f) How many years would it take to cut down the trees in all of the numbered
areas in Figure 2?

___________________________________________________________

___________________________________________________________

___________________________________________________________

Number of years = ____________________________________

(2)

(g) The rainforest contains:

• 750 species of trees

• 400 species of birds

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

• 150 species of butterflies

• many other species of plants and animals.

Explain how the pattern of cutting down trees shown in Figure 2 stops the
biodiversity of the rainforest being reduced.

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(4)
(Total 13 marks)

Q4.
Figure 1 shows a food chain in a pond.

Figure 1

(a) Which term describes the Daphnia in this food chain?

Tick (✓) one box.

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

Apex predator

Primary consumer

Producer

Secondary consumer

(1)

(b) Draw a pyramid of biomass for the food chain.

Label each trophic level.

(2)

(c) Give one reason why the total biomass of the Daphnia in the pond is
different from the total biomass of the algae.

___________________________________________________________

___________________________________________________________
(1)

Students investigated the size of the population of Daphnia in the pond.

This is the method used.

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

1. Collect 1 dm3 of pond water from near the edge of the pond.

2. Pour the water through a fine net.

3. Count the number of Daphnia caught in the net.

4. Repeat steps 1–3 four more times.

The table below shows the results.

Sample Number of Daphnia in

number 1 dm3 water
1 5
2 21
3 0
4 16
5 28

(d) Calculate the mean number of Daphnia in 1 m3 of pond water.

1 m3 = 1000 dm3

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___________________________________________________________

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___________________________________________________________

___________________________________________________________

Mean number of Daphnia in 1 m3 of pond water = ______________________

(2)

(e) The pond was a rectangular shape, measuring:

• length = 2.5 metres

• width = 1.5 metres

• depth = 0.5 metres.

Calculate the estimated number of Daphnia in the pond.

Use your answer from part (d).

Give your answer in standard form.

___________________________________________________________

___________________________________________________________

___________________________________________________________

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

___________________________________________________________

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Number of Daphnia in the pond = _______________________

(4)

Rainfall can cause fertiliser to be washed from farmland into a pond.

The students investigated the effect of fertiliser on the population of Daphnia in

water from the pond.

• The students put 20 Daphnia in each of five different concentrations of

fertiliser.

• The students counted the total number of Daphnia in each concentration of

fertiliser after 2 weeks.

Figure 2 shows the results.

Figure 2

(f) A concentration of 5.0 mg/dm3 of fertiliser caused a large increase in the

population of Daphnia.

Explain why.

___________________________________________________________

___________________________________________________________

___________________________________________________________

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

___________________________________________________________
(2)

(g) Figure 1 is repeated below.

Figure 1

The population of Hydra will decrease when 20 mg/dm3 of fertiliser is

added to the pond.

Explain why.

___________________________________________________________

___________________________________________________________

___________________________________________________________

___________________________________________________________
(2)
(Total 14 marks)

Q5.
Many scientists think that global air temperature is related to the concentration of
carbon dioxide in the atmosphere.

The graph below shows changes in global air temperature and changes in the
concentration of carbon dioxide in the atmosphere.

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

(a) Complete the table below.

Use information from the graph above.

Choose answers from the box.

You may use each answer once, more than once or not at all.

constant decreasing increasing

1960 − 1977 1977 − 2003 2003 − 2015

Trend in carbon dioxide

Increasing
concentration

Trend in air temperature

(2)

Many scientists think that an increase in carbon dioxide concentration in the

atmosphere causes an increase in air temperature.

(b) How would an increase in the concentration of carbon dioxide in the

atmosphere cause an increase in air temperature?

___________________________________________________________

___________________________________________________________
(1)

(c) Evaluate evidence for and against the theory that an increase in the

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

concentration of carbon dioxide in the atmosphere causes an increase in

air temperature.

Use data from the graph above and your own knowledge.

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(4)

In each year, the concentration of carbon dioxide in the atmosphere is higher in

the winter than in the summer.

(d) Give one human activity that could cause the higher concentration of
carbon dioxide in the winter.

___________________________________________________________

___________________________________________________________
(1)

(e) Give one biological process that could cause the lower concentration of
carbon dioxide in the summer.

___________________________________________________________

___________________________________________________________

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

(1)

(f) Give two possible effects of an increase in global air temperature on living
organisms.

1.
__________________________________________________________

___________________________________________________________

2.
__________________________________________________________

___________________________________________________________
(2)
(Total 11 marks)

Q6.
The graph below shows the area of forest lost in Madagascar from 2009 to 2012.

(a) The area of forest lost each year in Madagascar increased between 2009
and 2012.

Determine the total area of forest lost from the start of 2009 to the end of
2012.

___________________________________________________________

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

___________________________________________________________

Total area of forest lost = ___________ thousand hectares

(1)

(b) What are the possible reasons for the change in the area of forest lost per
year between 2009 and 2012?

Tick two boxes.

The local people stop growing rice

Fewer new houses are needed for the population

The local people decided to farm cattle

More trees have been planted

A company starts growing plants for biofuels

(2)

(c) More forest was lost in 2012 than in 2009.

Use words from the box to complete the sentences.

carbon dioxide excretion nitrogen

oxygen photosynthesis respiration

The increase in the area of forest lost has caused an increase in the gas

___________________________________________________________

The increase of this gas has been caused because less of the gas is being

absorbed by plants for the process of ______________________ .

(2)

(d) Deforestation can have negative effects on our ecosystems.

What are the negative effects of deforestation?

Tick two boxes.

Animals and birds migrate because there is less

food

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

More habitats are destroyed

There is less acid rain

There is more biodiversity

The global temperature decreases

(2)

(e) Scientists try to reduce the negative effects of human activity on our
ecosystems.

One way is to protect rare habitats.

Give one other way of reducing the negative effects of human activity on
our ecosystems.

___________________________________________________________

___________________________________________________________
(1)
(Total 8 marks)

Q7.
Human activity affects ecosystems.

(a) Draw one line from each human activity to the effect on ecosystems.

(2)

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

(b) (i) Deforestation also affects the atmosphere.

Give two reasons why deforestation takes place.

1. _____________________________________________________

_______________________________________________________

2. _____________________________________________________

_______________________________________________________
(2)

(ii) Changes in the gases in our atmosphere can cause global warming.

Give two possible effects of a rise in the Earth’s temperature.

1. _____________________________________________________

_______________________________________________________

2. _____________________________________________________

_______________________________________________________
(2)
(Total 6 marks)

Q8.
The figure below shows the amount of forest cover on an island in Asia, in 1973
and in 2010.

(a) (i) Deforestation has decreased the amount of forest cover on the
island.

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AQA Biology GCSE - Biodiversity & Effect of Humans on Ecosystems

Describe the change in the pattern of forest cover on the island.

_______________________________________________________

_______________________________________________________

_______________________________________________________

_______________________________________________________
(2)

(ii) Give two possible reasons why the amount of forest has decreased
between 1973 and 2010.

1.
_______________________________________________________

_______________________________________________________

2.
_______________________________________________________

_______________________________________________________
(2)

(b) Scientists are concerned about the effects of a decrease in forest cover on
ecosystems.

Give two possible negative effects of the decrease in forest cover on

ecosystems.

1.
__________________________________________________________

___________________________________________________________

2.
__________________________________________________________

___________________________________________________________
(2)
(Total 6 marks)

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