Habitat destruction — Cambridge IGCSE Combined Science

Biodiversity, the reasons habitats are destroyed, and the five undesirable effects of deforestation.

Spec B16.1Human influences on ecosystems, subtopic 1 of 2

Revision notes

2 short notes, in the order of the specification. Each one in short:

Biodiversity and habitat destruction
Biodiversity is the number of different species in an area; habitats are destroyed by housing, farming, resource extraction and pollution.
Deforestation
Deforestation reduces biodiversity, can cause extinction, soil loss and flooding, and raises atmospheric carbon dioxide as fewer trees photosynthesise.

5 exam-style questions (12 marks), each with its mark scheme.

4 cards: flip them, mark what you knew, and practise the rest.

The whole of human influences on ecosystems on one page, so you can see where this subtopic fits.

Free PDFs to print or save.

Define biodiversity.
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The number of different species that live in an area.
Give three reasons for habitat destruction.
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Housing, crop and livestock production; extraction of natural resources; freshwater and marine pollution.
Supplement How does deforestation lead to flooding?
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Fewer roots and leaves to absorb water, so more water runs into rivers.
Supplement How does deforestation increase carbon dioxide in the air?
Show answer
Fewer trees photosynthesise, and burning or decay of trees releases CO₂.

Written and checked against the Cambridge IGCSE Combined Science (0653) specification · Updated October 2026