# Explain how an invasive species can alter the realised niche of a native species within a community.

> IB DP Biology Standard Level (2023 syllabus) — B4.2 Ecological niches · Explain · 4 marks

## Mark scheme (4 marks)

1. The realised niche is the actual set of conditions and resources a species uses when biotic interactions (such as competition) are present.
2. An invasive species competes with the native species for overlapping resources (e.g. food, shelter, nesting sites).
3. Increased competition forces the native species to use a smaller or different set of resources, reducing / shifting its realised niche.
4. If the native species cannot adapt or shift its niche sufficiently, it may face population decline or local extinction, demonstrating competitive exclusion.

## Key terms

- [invasive species](https://www.gradenine.co.uk/glossary/invasive-species)
- [realised niche](https://www.gradenine.co.uk/glossary/realised-niche)

## Related

- [Revision notes for IB DP Biology Standard Level (2023 syllabus)](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/explain-how-an-invasive-species-can-3e8ac599) · Published by Druglandscape Ltd.