Explain why maintaining high biodiversity is important for the long-term survival of ecosystems.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
Model answer (4 marks)
1. A diverse range of species creates more stable food webs, reducing the chance of collapse.
2. If one species disappears, others can fill its ecological role or become an alternative food source, maintaining ecosystem function.
3. Many species supply resources humans rely on, such as medicines, food crops and materials.
4. The loss of a species can trigger negative effects on other species, causing a knock‑on effect throughout the ecosystem.
2. If one species disappears, others can fill its ecological role or become an alternative food source, maintaining ecosystem function.
3. Many species supply resources humans rely on, such as medicines, food crops and materials.
4. The loss of a species can trigger negative effects on other species, causing a knock‑on effect throughout the ecosystem.
Examiner tips
- Use the exact phrases from the mark scheme; show cause and effect.
- Show the link between species diversity and stability.
- Mention human benefits as a separate point.
- Keep each point brief and to the point.
Common mistakes
- Mixing up food chains with food webs; not distinguishing the two.
- Failing to mention the human resource aspect.
- Writing long, unfocused explanations instead of concise points.
Mark scheme (4 marks)
- A greater variety of species means more stable food webs / food chains
- If one species is lost, other species can fill the same role / act as an alternative food source, so the ecosystem is less likely to collapse
- Many species provide resources that humans depend on, such as medicines, food crops or materials
- Loss of one species can negatively affect other species / cause a knock-on effect through the ecosystem
Key terms in this question
Related
- All Eduqas GCSE Biology revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →