# Explain how a founder effect can influence the genetic diversity and future evolution of a newly established population.

> IB DP Biology Higher Level (2023 syllabus) — D4.2 Stability and change · Explain · 4 marks

## Mark scheme (4 marks)

1. A founder event occurs when a small number of individuals colonise a new habitat/area, representing only a subset of the original population's alleles.
2. The new population has reduced genetic diversity / lower allele richness compared to the source population due to this sampling error.
3. Allele frequencies in the new population differ from the source population by chance / random sampling, so some alleles may be at unexpectedly high or low frequency.
4. The altered allele frequencies and reduced diversity constrain future evolution, potentially leading to rapid divergence / speciation or increased prevalence of previously rare recessive conditions in the new population.

## Key terms

- [founder effect](https://www.gradenine.co.uk/glossary/founder-effect)
- [genetic diversity](https://www.gradenine.co.uk/glossary/genetic-diversity)

## 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-a-founder-effect-can-50cf3cd3) · Published by Druglandscape Ltd.