A4.1 Evolution and speciation

Evolution and speciation explain how heritable variation, molecular evidence, selection, isolation, and chromosome change produce population divergence and new species over time.

What you’ll learn

11 learning objectives

Choose one objective for a focused lesson, or study the complete topic.

Exam analysis

An aggregate view of how the complete A4.1 Evolution and speciation appears across past papers.

Chance of appearing36%of analysed past papers

Latest appearanceNovember 2025

Most common paperPaper1

Most tested objectives

A4.1.4—Evidence from homologous structures20 questions
A4.1.6—Speciation by splitting of pre-existing species15 questions
A4.1.1—Evolution as change in heritable characteristics14 questions

Common question formats

Definition or recall
Process explanation
Data analysis
Comparison
Evaluation

Exam question appearances

November 2025Paper2 ["SL"] · TZ17(a)[ 4 ]A4.1.5—Convergent evolution

November 2025Paper1A ["HL"] · TZ333[ 1 ]A4.1.5—Convergent evolution

November 2025Paper1A ["SL"] · TZ122[ 1 ]A4.1.7—Reproductive isolation and differential selection

May 2025Paper2 ["HL"] · TZ29(a)[ 4 ]A4.1.4—Evidence from homologous structures

May 2025Paper2 ["HL"] · TZ38(c)[ 4 ]A4.1.11 (HL)—Abrupt speciation in plants

Practice this topic

11 original exam-style questions based on the patterns above.

Coverage 2010–2025 · Updated 15 Jul 2026