Explain why a freshwater pond is described as an ecosystem.
Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).
A freshwater pond contains water, dissolved minerals, mud, aquatic plants, algae, insects, fish, and decomposing leaf litter from nearby trees.
Model answer (4 marks)
A freshwater pond is an ecosystem because it contains both biotic and abiotic components. The biotic part includes aquatic plants, algae, insects, fish and decomposing leaf litter, while the abiotic part consists of water, dissolved minerals, mud and light. The organisms interact with each other through feeding relationships and competition, and they also interact with the abiotic environment – for example, the water and minerals influence their growth and the light determines photosynthesis.
Examiner tips
- Use the words ‘biotic’ and ‘abiotic’ explicitly
- Show the two types of interaction: biotic‑biotic and biotic‑abiotic
- Keep the answer concise and to the point
Common mistakes
- Failing to mention both biotic and abiotic components
- Using vague terms like ‘living things’ without specifying biotic/abiotic
- Leaving out the interaction between organisms and the environment
Mark scheme (4 marks)
- A pond contains living (biotic) components / organisms
- A pond contains non-living (abiotic) components such as water, minerals, or light
- The living organisms interact with each other (e.g. feeding relationships / competition)
- The living organisms interact with the non-living environment / abiotic factors affect the organisms
Key terms in this question
Related
- All Eduqas GCSE Biology revision notes →
- How to answer a "Explain" question →
- Decode the mark scheme abbreviations →
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