# Explain how resource partitioning allows two species with overlapping fundamental niches to coexist within the same habitat.

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

## Mark scheme (4 marks)

1. Species with overlapping fundamental niches would, without partitioning, compete for the same resources, potentially leading to competitive exclusion of one species.
2. Resource partitioning involves each species utilising a different subset of the available resources (e.g. different food sizes, foraging heights, or activity times), thereby reducing niche overlap.
3. The realised niche of each species is narrower than its fundamental niche as a result of this differentiation, but coexistence is possible because direct competition is minimised.
4. Over evolutionary time, natural selection may reinforce partitioning through character displacement, where traits (e.g. beak size, body size) diverge, making resource use differences more pronounced and stable.

## Key terms

- [resource partitioning](https://www.gradenine.co.uk/glossary/resource-partitioning)
- [fundamental niche](https://www.gradenine.co.uk/glossary/fundamental-niche)

## 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)
- [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-resource-partitioning-allows-two-34438fe9) · Published by Druglandscape Ltd.