stabilising selection
What stabilising selection means in Biology A-Level, as defined for AQA.
Definitions of stabilising selection
Exam boards and our study guides word this term in slightly different ways. Learn the version your board uses.
Check what you remember
Read the wording for your board, then hide it and explain stabilising selection in your own words. Rough notes are fine. This is a self-check, with no mark or grade.
Reference: AQA
Individuals at both extremes are selected against and those near the mean have the advantage, so the mean stays the same while the range narrows and the curve becomes taller and thinner.
Favours the intermediate phenotype and selects against both extremes, so the mean stays where it is while the standard deviation falls and the distribution curve narrows.
Topics that use stabilising selection
- Evolution may lead to speciation (A-level only) (AQA A-Level)
- Genetic diversity and adaptation (AQA A-Level)
Related terms
- directional selection
- advantage depends on environment
- allele
- allele frequency change
- allele passed to offspring
- allopatric speciation
- altered tertiary structure
- aseptic technique
Using stabilising selection in the exam
Check the command word and mark scheme for your exact question. After comparing your explanation with the reference, use the term in an answer on the linked topic. This practice does not predict an exam mark.
Practise Biology questions
Create a free account to answer exam-style questions on this topic and get feedback on your answers.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge