Q BankQuestion BankDocsDocuments

A4.1.4—Evidence from homologous structures

Homologous structures share evolutionary origin even when functions differ, providing anatomical evidence for common ancestry, divergent adaptation, and adaptive radiation.

Syllabus
First assessment 2025
Objective
A4.1.4
Level
HL

Exam analysis

Chance of appearing7%of analysed past papers
Latest appearanceMay 2025
Most common paperPaper1
Typical marks1–4

Common command terms

  • Describe
  • Outline

Scoring notes

Common mistake
Confusing homologous structures with analogous structures that share a function but not evolutionary origin.

Recent exam appearances

May 2025Paper2 ["HL"] · TZ29(a)[ 4 ]A4.1.4—Evidence from homologous structures
May 2021Paper2 ["HL"] · TZ17(c)[ 4 ]A4.1.4—Evidence from homologous structures
May 2021Paper1 ["HL"] · TZ115[ 1 ]A4.1.4—Evidence from homologous structures
November 2019Paper1 ["HL"] · TZ017[ 1 ]A4.1.4—Evidence from homologous structures
May 2018Paper1 ["HL"] · TZ225[ 1 ]A4.1.4—Evidence from homologous structures
Practice this objective

Coverage 2016–2025 · Updated 15 Jul 2026

Concept essentials

  • Homologous structures share ancestral origin and underlying anatomy.
  • Pentadactyl limbs are evidence of common ancestry among vertebrate groups.
  • Different functions in homologous structures reflect divergent evolution and adaptive radiation.
  • Natural classification relies more on homologous traits than on analogous similarities.
ConceptIB Biology HL