Describe four ways in which human activities can reduce biodiversity.

WJEC GCSE Biology (Wales) — 2.1.2 Biodiversity · Describe · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

1. Deforestation or habitat destruction removes the living space and food sources of many species, leading to population decline or local extinction.
2. Pollution, such as pesticides, fertilisers or industrial waste, kills or harms organisms in an ecosystem.
3. Overhunting or overfishing reduces populations of species to the point of extinction or collapse.
4. Introduction of invasive or non‑native species outcompetes native species for resources, reducing their numbers.

Examiner tips

Use the exact phrases from the mark scheme, e.g. "deforestation / habitat destruction", "pollution (e.g. pesticides, fertilisers, industrial waste)", "overhunting / overfishing", "invasive / non‑native species".
Show each point as a separate bullet or numbered item to demonstrate clear structure.
Include the word "reduces" or "causes" to link the activity to the loss of biodiversity.

Common mistakes

Using vague terms like "human impact" instead of the specific activities listed.
Failing to mention the direct link between the activity and the loss of biodiversity, e.g. not stating that deforestation removes food sources.

Mark scheme (4 marks)

Deforestation / habitat destruction removes the living space and food sources of many species, causing population decline or local extinction
Pollution (e.g. pesticides, fertilisers, industrial waste) kills or harms organisms in an ecosystem
Overhunting / overfishing reduces populations of species to the point of extinction or collapse
Introduction of invasive / non-native species outcompetes native species for resources, reducing their numbers

Key terms in this question

biodiversity