Evaluate the claim that modern farming methods reduce biodiversity within a community.

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

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

Intensive farming techniques, such as monoculture cropping and the use of pesticides, are widely used across the UK to increase food production.

Model answer (5 marks)

Monoculture cropping removes many plant species, so the number of plant types in a community falls.

With fewer plant species, the variety of habitats and food sources for animals also decreases, so animal species diversity is reduced.

Pesticides kill insects and other herbivores that are part of food chains and food webs, further lowering biodiversity.

A community with lower biodiversity is less stable and more vulnerable to disease outbreaks or environmental changes.

However, modern farming is essential for feeding a growing population; not all farming practices reduce biodiversity equally, so a balance must be considered.

Examiner tips

  • Use the exact terms from the mark scheme (e.g., ‘monoculture’, ‘pesticides’, ‘food webs’).
  • Show the logical chain: plant loss → habitat loss → animal loss → instability.
  • Include the counter‑point to demonstrate critical evaluation.
  • Keep each point brief and to the point to fit the 5‑mark limit.

Common mistakes

  • Writing a long essay instead of concise points.
  • Omitting the counter‑point or the stability argument.
  • Using vague words like ‘less’ instead of ‘reduced’ or ‘decreased’.

Mark scheme (5 marks)

  1. Monoculture reduces the number of different plant species present / reduces variety of plant species
  2. Fewer plant species means fewer habitats / food sources for animals, reducing animal species diversity
  3. Pesticides kill insects / herbivores that are part of food chains / food webs
  4. Reduced biodiversity makes the community less stable / more vulnerable to disease or environmental change
  5. Counter-point / limitation: farming is needed to feed a growing human population, so a balance must be considered / not all farming reduces biodiversity equally

Key terms in this question

biodiversity · community

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