# Describe how energy is lost from a food chain at each trophic level, and explain why this means food chains rarely have more than five trophic levels.

> AQA A-Level Biology (7402) — 3.5.3 Energy and Ecosystems · Describe and Explain · 5 marks

## Mark scheme (5 marks)

1. Energy is lost through heat produced during respiration
2. Energy is lost in waste materials such as urine or faeces / undigested material in faeces is not absorbed
3. Only a small proportion / percentage of energy taken in is passed on to the next trophic level
4. So the amount of energy available decreases at each successive trophic level
5. After several trophic levels there is insufficient energy remaining to support another level / organism at the next level

## Key terms

- [trophic level](https://www.gradenine.co.uk/glossary/trophic-level)

## Related

- [Revision notes for AQA A-Level Biology (7402)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-energy-is-lost-from-e55bb979) · Published by Druglandscape Ltd.