# Describe how the classification of living organisms changed when Carl Woese developed the three-domain system.

> AQA GCSE Biology (8461) — 4.6.4 Classification of living organisms · Describe · 4 marks

## Mark scheme (4 marks)

1. The Linnaean system classified organisms into kingdoms (e.g. kingdom, phylum, class, order, family, genus, species)
2. Carl Woese developed the three-domain system as a new / different method of classification
3. Organisms are now grouped into three domains: Archaea, Bacteria and Eukaryota
4. Archaea are primitive bacteria / microorganisms that live in extreme environments, recognised as separate from (true) Bacteria

## Key terms

- [three-domain system](https://www.gradenine.co.uk/glossary/three-domain-system)
- [classification](https://www.gradenine.co.uk/glossary/classification)

## Related

- [Revision notes for AQA GCSE Biology (8461)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/describe-how-the-classification-of-living-632fa741) · Published by Druglandscape Ltd.