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CAIE IGCSE Biology 20.2 Habitat Destruction Questions

Practise habitat-destruction questions by defining biodiversity, explaining forest clearance and linking deforestation to soil, flooding and carbon dioxide.

Syllabus
2026–2028
Course
Biology 0610

Exam points

  • define biodiversity as the number of different species that live in an area and distinguish it from population size
  • describe how fertiliser changes plant species diversity using graph trends and data
  • link land clearance to housing, crop production and livestock production
  • identify logging, mining or other extraction of natural resources as causes of habitat destruction
  • identify pollution as a human cause of habitat destruction
  • trace how killing producers or non-target species disrupts food chains and reduces biodiversity
  • evaluate pesticide damage using toxicity, persistence, application method and resistance risk
  • link habitat and food-web loss to reduced biodiversity and species extinction
  • explain how loss of roots and canopy increases soil erosion, runoff and flooding
  • explain higher atmospheric carbon dioxide through reduced photosynthesis, decay or burning

Covered syllabus points

20.2.1—Biodiversity as the number20.2.2—Reasons for habitat destruction20.2.3—Through altering food webs and food20.2.4—Undesirable effects of deforestation

Question 1

[Maximum number: 1]

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

A

biodiversity

B

conservation

C

ecosystem

D

population

Question 2

[Maximum number: 3]

Forest ecosystems are threatened by many human activities.

Describe reasons why people cut down forests.

Question 3

[Maximum number: 4]

Some crop farmers use herbicides on their fields.
Fig. 4.1 shows a farmer spraying a rice crop with herbicides.

Fig. 4.1

Fig. 4.1

Fields of crop plants were sprayed with two herbicides. A farmer measured the concentration of the two herbicides, A and B, in a lake near the fields.

The water in the lake was sampled at intervals for two weeks.
Fig. 4.2 shows the results.
concentration of herbicides in the lake water samples / mg per kg

Fig. 4.2

Fig. 4.2

Suggest how herbicides damage ecosystems in a lake.

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