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D4.1.11 (HL)—Changes in allele frequency

Allele frequencies change when selection, mutation, migration, genetic drift or non-random mating alters reproductive contribution in evolving populations in evolving populations.

Syllabus
First assessment 2025
Objective
D4.1.11
Level
HL

Exam analysis

Chance of appearing4%of analysed past papers
Latest appearanceMay 2023
Most common paperPaper2
Typical marks1–4

Common command terms

  • Compare
  • Outline

Recent exam appearances

May 2023Paper1 ["HL"] · TZ116[ 1 ]D4.1.11 (HL)—Changes in allele frequency
May 2016Paper2 ["HL"] · TZ03(c)[ 2 ]D4.1.11 (HL)—Changes in allele frequency
May 2016Paper3 ["HL"] · TZ010(a)(i)[ 1 ]D4.1.11 (HL)—Changes in allele frequency
May 2015Paper2 ["HL"] · TZ24(c)[ 4 ]D4.1.11 (HL)—Changes in allele frequency
Practice this objective

Coverage 2015–2023 · Updated 16 Jul 2026

Concept essentials

  • Selection changes allele frequencies through differential reproductive success.
  • Genetic drift is random and strongest in small populations.
  • Migration can add or remove alleles from a population.
ConceptIB Biology HL