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CAIE IGCSE Biology 20 Human Influences on Ecosystems Questions

Practise evaluating how food production, habitat loss, pollution and conservation alter biodiversity and ecosystem stability.

Syllabus
2026–2028
Course
Biology 0610

Covered syllabus points

20.1 Food supply20.2 Habitat destruction20.3 Pollution20.4 Conservation

Question 1

[Maximum number: 3]

Phloem is used to transport sucrose and amino acids in plants. Sucrose is a carbohydrate.

Aphids are used by investigators to discover how plants transport sucrose.

Fig. 2.2 shows an aphid with its mouthparts inserted into a plant stem to feed on the liquid in the phloem.

Fig. 2.2

Fig. 2.2

A plant was put in a dark cupboard for several days.
Four aphids, A, B, C and D, were then placed on the plant in the dark cupboard as shown in Fig. 2.3.

Fig. 2.3

Fig. 2.3

Many crop farmers try to prevent insects such as aphids from damaging their plants.

Describe how modern technology is used to reduce damage to crop plants by insects.

Question 2

[Maximum number: 1]

Which term describes the number of different species living in an area?

A

biodiversity

B

conservation

C

ecosystem

D

population

Question 3

[Maximum number: 7]

Question (a)

(a)

Fig. 6.1 shows part of the carbon cycle in the ocean.

Fig. 6.1 (not to scale)

Fig. 6.1 (not to scale)

[ 3 ]

Question (i)

(i)

Describe the effect on the environment of additional carbon dioxide in the atmosphere.

[ 3 ]

Question (b)

(b)

The oceans contain fish stocks that can be managed as a sustainable resource to provide food for humans.

[ 4 ]

Question (i)

(i)

State what is meant by the term sustainable resource.

[ 2 ]

Question (ii)

(ii)

Fishing can be managed to promote the conservation of fish stocks.

Explain one way that fishing can be managed to conserve fish stocks.

[ 2 ]

Question 4

[Maximum number: 2]

Fig. 4.1 is a flow chart showing some of the processes that occur in a biofuels power plant.

Fig. 4.1

Fig. 4.1

Farmers grow giant reed plants as monocultures.

Describe the disadvantages of growing giant reed plants to provide biomass for the production of biofuels.

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