# A wildlife organisation is investigating the carbon cycle in a woodland ecosystem. The woodland contains producers, primary consumers, secondary consumers, and decomposers. Explain how carbon moves from the atmosphere into living organisms and then back into the atmosphere in this woodland ecosystem.

> OCR A-Level Biology B — Advancing Biology (H422) — 4.3 Energy budgets and ecosystems · Explain · 5 marks

> Carbon is continuously cycled through the biotic and abiotic components of ecosystems. In a woodland, this cycling involves several different biological processes and groups of organisms.

## Mark scheme (5 marks)

1. Carbon dioxide is removed from the atmosphere by producers (plants) through photosynthesis
2. Carbon passes along the food chain when consumers eat producers (or other consumers)
3. Carbon dioxide is returned to the atmosphere when living organisms respire
4. Decomposers break down dead organisms / decaying matter, releasing carbon dioxide through decomposition / respiration
5. Carbon can also be returned to the atmosphere through combustion of organic matter

## Key terms

- [carbon cycle](https://www.gradenine.co.uk/glossary/carbon-cycle)
- [decomposer](https://www.gradenine.co.uk/glossary/decomposer)

## Related

- [Revision notes for OCR A-Level Biology B — Advancing Biology (H422)](https://www.gradenine.co.uk/learn)
- [How to answer "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/a-wildlife-organisation-is-investigating-the-3a685600) · Published by Druglandscape Ltd.