Q BankQuestion BankDocsDocuments

A4.1.5—Convergent evolution

Convergent evolution produces analogous structures when unrelated lineages experience similar selection pressures and independently evolve comparable functional solutions in separate environments.

Syllabus
First assessment 2025
Objective
A4.1.5
Level
HL

Exam analysis

Chance of appearing3%of analysed past papers
Latest appearanceNovember 2025
Most common paperPaper3
Typical marks1–2

Common command terms

  • Compare
  • Distinguish
  • State
  • Outline
  • Explain

Scoring notes

Common mistake
Calling analogous structures homologous because they have the same function.

Recent exam appearances

November 2025Paper1A ["HL"] · TZ333[ 1 ]A4.1.5—Convergent evolution
May 2014Paper3 ["HL"] · TZ22(c)[ 1 ]A4.1.5—Convergent evolution
May 2012Paper3 ["HL"] · TZ1D2(c)[ 2 ]A4.1.5—Convergent evolution
Practice this objective

Coverage 2012–2025 · Updated 15 Jul 2026

Separate Homology From Convergence

A split visual. Left side compares vertebrate pentadactyl limbs with the same basic bone plan adapted for different functions such as grasping, flight, running, and swimming. Right side compares bat and insect wings to show similar function but different evolutionary origins.

Homologous and analogous structures answer different evolutionary questions. Homologous structures share a basic structural pattern and common ancestry, even when their functions differ. The pentadactyl limb in vertebrates has the same underlying arrangement of bones adapted for grasping, flight, running or swimming; it is evidence of divergent evolution.

Analogous structures have similar functions but different structural origins and ancestry. Bat wings and insect wings both support flight, but their underlying construction and evolutionary origins differ. They are evidence of convergent evolution: similar selection pressures produced similar functions independently. In an exam, compare structure and ancestry, not function alone.

Convergent evolution

Assessment in practice

1–2 marks
How it is assessed

This objective is assessed through essay response, commonly using Compare / Distinguish / State.

Command terms

Compare / Distinguish / State / Outline / Explain

What earns marks

Build the answer around this relationship: Convergent evolution produces similar adaptations in lineages with different evolutionary origins.

Watch for

Calling analogous structures homologous because they have the same function.

Representative question

Question 1

[Maximum number: 4]

Explain how analogous structures can evolve.

SL Transfer: Evidence To Speciation

The core A4.1 answer moves from evidence to mechanism. Define evolution as heritable population change across generations. Use molecular universals and sequence differences, selective breeding, homology, and convergence as evidence for common ancestry and divergence. Then explain speciation as reduced gene flow followed by divergence of isolated gene pools through selection, mutation, and drift.

  • Evolution is cumulative change in heritable characteristics of a population.
  • Molecular evidence supports common ancestry and divergence.
  • Selective breeding shows heritable traits can change rapidly under selection.
  • Homology supports common ancestry; analogy/convergence shows similar selection pressures can mislead.
  • Speciation needs reduced gene flow and divergence of isolated gene pools.

Concept essentials

  • Convergent evolution produces similar adaptations in lineages with different evolutionary origins.
  • Analogous structures have similar functions but are not inherited from the same recent ancestral structure.
  • Similar selection pressures can favour comparable solutions in unrelated organisms.
  • Divergent evolution produces homologous differences from a shared ancestral structure.
ConceptIB Biology HL