# Explain how the kingdom Protista is considered paraphyletic and discuss the implications of this for its status as a valid taxonomic group.

> IB DP Biology Higher Level (2023 syllabus) — A3.1 Diversity of organisms · Explain · 4 marks

## Mark scheme (4 marks)

1. Protista is paraphyletic because it includes a common ancestor but does not include all of its descendants
2. Protista is an artificial/convenience grouping that contains phylogenetically unrelated or distantly related lineages
3. A valid clade (monophyletic group) must include a common ancestor and ALL of its descendants, which Protista fails to satisfy
4. The implication is that Protista should be dissolved/replaced by multiple monophyletic groups, or at least that it is no longer considered a valid kingdom in phylogenetic classification systems

## Key terms

- [paraphyletic](https://www.gradenine.co.uk/glossary/paraphyletic)
- [Protista](https://www.gradenine.co.uk/glossary/protista)
- [kingdom](https://www.gradenine.co.uk/glossary/kingdom)

## Related

- [Revision notes for IB DP Biology Higher Level (2023 syllabus)](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-how-the-kingdom-protista-is-a86e9740) · Published by Druglandscape Ltd.