# A student finds two beetles in a garden. Beetle A and Beetle B look very similar but a scientist says they belong to different species. Explain what is meant by the term 'species' and describe how scientists use observable features and DNA evidence to decide whether two organisms belong to the same species or different species.

> Pearson Edexcel A-Level Biology A (9BI0) — Topic 3 Classification and Biodiversity · Explain · 5 marks

> Two beetles are found in the same garden. They look almost identical in colour and size, but genetic analysis reveals significant differences in their DNA sequences.

## Mark scheme (5 marks)

1. A species is a group of organisms that can interbreed / reproduce sexually to produce fertile offspring
2. Scientists observe similarities and differences in the physical / observable features (morphology) of organisms to classify them
3. If two organisms share many similar observable features they are likely to be in the same / closely related species or group
4. Scientists compare DNA sequences between the two organisms
5. Greater differences in DNA sequences indicate the organisms are from different species / less closely related, so the beetles are classified as different species

## Key terms

- [species](https://www.gradenine.co.uk/glossary/species)
- [observable features](https://www.gradenine.co.uk/glossary/observable-features)

## Related

- [Revision notes for Pearson Edexcel A-Level Biology A (9BI0)](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-student-finds-two-beetles-in-d7f8f9c1) · Published by Druglandscape Ltd.