Human activities such as deforestation and pollution can reduce biodiversity. Explain how a reduction in biodiversity can have negative consequences for ecosystems and for humans.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
Fewer species mean food webs become less stable; if one species is lost, predators or prey that depend on it may also disappear.
Reduced biodiversity lowers an ecosystem’s resilience, making it less able to recover from disturbances such as disease outbreaks or climate change.
Loss of species reduces the pool of potential medicines, as many drugs are derived from wild organisms.
Reduced biodiversity can threaten food security, because the loss of crop varieties or wild relatives limits options for breeding disease‑resistant or high‑yielding crops.
Reduced biodiversity lowers an ecosystem’s resilience, making it less able to recover from disturbances such as disease outbreaks or climate change.
Loss of species reduces the pool of potential medicines, as many drugs are derived from wild organisms.
Reduced biodiversity can threaten food security, because the loss of crop varieties or wild relatives limits options for breeding disease‑resistant or high‑yielding crops.
Examiner tips
- Use the exact terms ‘food webs’, ‘resilience’, ‘medicine’, ‘food security’.
- Show cause–effect links: loss → instability, loss → reduced resilience, loss → fewer medicines, loss → less crop diversity.
Common mistakes
- Confusing biodiversity with population size; the question asks about species diversity. Failing to link loss of species to specific human impacts such as medicine or crop breeding.
Mark scheme (4 marks)
- Fewer species means food webs/chains become less stable / if one species is lost, other species that depend on it may also be lost
- Reduced biodiversity decreases the resilience of an ecosystem to change / less able to recover from disturbances such as disease or climate change
- Loss of species reduces the potential for discovering new medicines / many medicines originally come from wild organisms
- Reduced biodiversity can affect food security for humans / loss of crop varieties or wild relatives of crops reduces options for breeding disease-resistant or high-yielding crops
Key terms in this question
Related
- All Eduqas GCSE Biology revision notes →
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- Decode the mark scheme abbreviations →
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