Describe how human activities can reduce biodiversity within a community. In your answer, give two different human activities and for each one explain how it leads to a reduction in biodiversity.

AQA A-Level Biology (7402) — 3.4.6 Biodiversity Within a Community · Describe · 5 marks · View as Markdown

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

Model answer (5 marks)

Deforestation removes habitats, so fewer species can survive and many become extinct.

Industrial pollution releases toxins into water and air, killing organisms and reducing the number of species that can live there.

These activities reduce biodiversity because they lower the variety and number of different species in the community.

Examiner tips

Use clear, concise sentences; include the activity name and a direct link to loss of species; finish with a statement linking to the definition of biodiversity.
Remember to separate the two activities with a line break or bullet for clarity.

Common mistakes

Using vague terms like "human impact" without naming a specific activity; not explicitly stating how the activity reduces species numbers; failing to mention the definition of biodiversity at the end.

Mark scheme (5 marks)

Names a relevant human activity (e.g. deforestation / habitat destruction / pollution / monoculture farming / urban development / overhunting / introduction of invasive species)
Explains how that first activity reduces biodiversity (e.g. deforestation removes habitats so fewer species can survive / fewer species present / species become extinct)
Names a second, different relevant human activity
Explains how that second activity reduces biodiversity (e.g. pollution kills organisms so fewer species survive / monoculture removes variety of plant species and reduces food sources for animals)
Explains that biodiversity is reduced because there is a smaller variety / number of different species (or a link is made to the definition: the variety of living organisms in an area)

Key terms in this question

biodiversity · community