# Explain why the classification of organisms sometimes changes, and describe two types of evidence scientists use to determine whether organisms should be placed in the same group.

> AQA A-Level Biology (7402) — 3.4.5 Species and Taxonomy · Explain · 5 marks

## Mark scheme (5 marks)

1. Classification changes because new evidence becomes available / as scientific understanding develops
2. Molecular / genetic evidence (e.g. DNA or genome sequencing) can reveal how closely related organisms are
3. Organisms with more similar DNA / genes are placed in the same / closer groups
4. Physical / morphological characteristics (e.g. body structure, observable features) are used as evidence
5. Organisms with more similar physical characteristics are placed in the same group / closer together in the hierarchy

## Key terms

- [classification](https://www.gradenine.co.uk/glossary/classification)
- [evidence](https://www.gradenine.co.uk/glossary/evidence)

## Related

- [Revision notes for AQA A-Level Biology (7402)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-the-classification-of-organisms-12d22594) · Published by Druglandscape Ltd.