IGCSE Biology (9–1) 0970 · Topic 20

Human influences on ecosystems: past paper questions

128 real questionsasked in 10 of the last 10 exam series2019–2026usually: Describe, State, Suggest, Explain, Complete

Real questions on human influences on ecosystems

The newest 20 of 81 written questions, plus 47 multiple-choice. Open one to see it on the real paper.

0970/31 · May/June 2026 · Q8a[4]
Describe reasons why animals such as the Arabian oryx become extinct in the wild.
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0970/32 · May/June 2026 · Q6d(i)[2]
The list shows five conclusions. Tick (“) two correct conclusions for the data shown in Figure 6.3. The percentage of nests with plastic was above 25% for all species. The percentage of nests with plastic was higher for species C than for species A. The percentage of nests with plastic was highest for species E. The pe...
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0970/32 · May/June 2026 · Q6d(ii)[2]
Suggest two disadvantages to birds of having nests containing non-biodegradable plastic.
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0970/32 · May/June 2026 · Q6e[3]
The population of great cormorants has decreased over time due to habitat destruction. Describe reasons, other than plastic pollution, for habitat destruction.
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0970/41 · May/June 2026 · Q5a(ii)[3]
Using the information in Table. 5.1, suggest the advantages to the environment of polyculture farming compared to monoculture farming.
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0970/41 · May/June 2026 · Q5b(ii)[1]
Describe how herbicides can increase the yield of crop plants.
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0970/41 · May/June 2026 · Q5c[4]
(c) .......... farming deforestation. Explain how deforestation can contribute to climate change.
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0970/42 · May/June 2026 · Q2a[2]
Describe what is meant by a sustainable resource.
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0970/42 · May/June 2026 · Q2d[4]
One way of conserving wild fish stocks is to regulate the size of the holes in the nets that are used to catch the fish. Explain how this helps to conserve fish stocks.
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0970/42 · May/June 2026 · Q2e[6]
Some species are threatened with extinction. Explain the reasons why species become endangered.
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0970/61 · May/June 2026 · Q3b(v)[3]
Using the data in Table 3.1, calculate the percentage change in the potato crop yield when the mass of fertiliser used was increased from 60 kg per hectare to 285kg per hectare. Give your answer to three significant figures. Space for working.
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0970/32 · October/November 2025 · Q3b[3]
Pathogens are one cause of deforestation. Describe other causes of deforestation.
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0970/32 · October/November 2025 · Q3c[3]
Fig. 3.2 shows the area of rainforest that was removed between 2004 and 2022 in one country. 30 25 area of rainforest 20 removed in one country / thousand 15 km 2 10 5 2004 2007 2010 2013 year 2016 2019 2022 Fig. 3.2 Describe the data shown in Fig. 3.2.
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0970/32 · October/November 2025 · Q3d(i)[2]
Describe what is meant by the term biodiversity.
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0970/32 · October/November 2025 · Q3d(ii)[3]
Describe undesirable effects of deforestation, other than reducing biodiversity.
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0970/42 · October/November 2025 · Q4b(i)[3]
Explain the risks to a species of a captive breeding programme that uses such a small number of individuals.
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0970/42 · October/November 2025 · Q4b(ii)[4]
Suggest ways of maintaining a population of Przewalski’s horse in the wild after their reintroduction to the steppe ecosystem.
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0970/42 · October/November 2025 · Q5a[3]
Discuss the advantages of intensive livestock production.
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0970/42 · October/November 2025 · Q5b[2]
One disadvantage of intensive livestock production is that antibiotics are often used. Suggest why antibiotics are needed in intensive livestock production.
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0970/42 · October/November 2025 · Q5c(i)[1]
State the letters of the countries in Fig. 5.1 that used less than the suggested limit of 50 mg of antibiotics per kg of livestock in 2016. (i)
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What examiners said

The majority could not convert cm to mm – answers ranged from 5000 to 50.
— Examiner report, May/June 2025, 0970/31 Q7(a)(i) (Cambridge)

A few got the types of plastic the wrong way round. Some stated that macroplastics and microplastics were present from the start, or 1960. Many got the mark for macroplastics increasing, but they found it difficult to express the change in microplastics correctly with the appropriate years. Several only got half the story and did not make relevant comparisons. Many did not make correct data quotes...
— Examiner report, May/June 2025, 0970/31 Q7(a)(ii) (Cambridge)

Most candidates gave at least one correct answer, usually about eating the plastics or getting tangled. Some described damage to the ecosystem, or toxin release rather than damage to the individual animal. Frequently the idea of blocking out sunlight leading to eutrophication was mentioned.
— Examiner report, May/June 2025, 0970/31 Q7(b) (Cambridge)

Practise this topic

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Practise these questions

In the syllabus

20.1 Food supply

Describe how humans have increased food production, limited to: (a) agricultural machinery to use larger areas of land and improve efficiency (b) chemical fertilisers to improve yields (c) insecticides to improve quality and yield (d) herbicides to reduce competition with weeds (e) selective breeding to improve production by crop plants and livestock
Describe the advantages and disadvantages of large-scale monocultures of crop plants
Describe the advantages and disadvantages of intensive livestock production

20.2 Habitat destruction

Describe biodiversity as the number of different species that live in an area
Describe the reasons for habitat destruction, including: (a) increased area for housing, crop plant production and livestock production (b) extraction of natural resources (c) freshwater and marine pollution
State that through altering food webs and food chains, humans can have a negative impact on habitats
Explain the undesirable effects of deforestation as an example of habitat destruction, to include: reducing biodiversity, extinction, loss of soil, flooding and increase of carbon dioxide in the atmosphere

20.3 Pollution

Describe the effects of untreated sewage and excess fertiliser on aquatic ecosystems
Describe the effects of non-biodegradable plastics, in both aquatic and terrestrial ecosystems
Describe the sources and effects of pollution of the air by methane and carbon dioxide, limited to: the enhanced greenhouse effect and climate change
Explain the process of eutrophication of water, limited to: • increased availability of nitrate and other ions • increased growth of producers • increased decomposition after death of producers • increased aerobic respiration by decomposers • reduction in dissolved oxygen • death of organisms requiring dissolved oxygen in water

20.4 Conservation

Describe a sustainable resource as one which is produced as rapidly as it is removed from the environment so that it does not run out
State that some resources can be conserved and managed sustainably, limited to forests and fish stocks
Explain why organisms become endangered or extinct, including: climate change, habitat destruction, hunting, overharvesting, pollution and introduced species
Describe how endangered species can be conserved, limited to: (a) monitoring and protecting species and habitats (b) education (c) captive breeding programmes (d) seed banks
Explain how forests can be conserved using: education, protected areas, quotas and replanting
Explain how fish stocks can be conserved using: education, closed seasons, protected areas, controlled net types and mesh size, quotas and monitoring
Describe the reasons for conservation programmes, limited to: (a) maintaining or increasing biodiversity (b) reducing extinction (c) protecting vulnerable ecosystems (d) maintaining ecosystem functions, limited to nutrient cycling and resource provision, including food, drugs, fuel and genes
Describe the use of artificial insemination (AI) and in vitro fertilisation (IVF) in captive breeding programmes
Explain the risks to a species if its population size decreases, reducing genetic variation (knowledge of genetic drift is not required)

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