D4.1 Natural selection

Natural selection explains how heritable variation, selection pressures, differential survival, reproduction and allele-frequency changes drive evolutionary adaptation in populations in evolving populations.

What you’ll learn

15 learning objectives

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

Exam analysis

An aggregate view of how the complete D4.1 Natural selection appears across past papers.

Chance of appearing42%of analysed past papers

Latest appearanceNovember 2025

Most common paperPaper3

Most tested objectives

D4.1.1—Natural selection as mechanism13 questions
D4.1.12 (HL)—Types of selection11 questions
D4.1.13 (HL)—Hardy-Weinberg equation8 questions

Common question formats

Process explanation
Data analysis
Definition or recall
Calculation
Diagram interpretation
Experimental design
Comparison

Exam question appearances

November 2025Paper1B ["HL"] · TZ34(d)[ 3 ]D4.1.9 (HL)—Gene pool concept

November 2025Paper1B ["HL"] · TZ14(d)[ 4 ]D4.1.8—Modelling selection

November 2025Paper1B ["HL"] · TZ14(c)[ 2 ]D4.1.8—Modelling selection

November 2025Paper1A ["HL"] · TZ338[ 1 ]D4.1.13 (HL)—Hardy-Weinberg equation

November 2025Paper1A ["HL"] · TZ138[ 1 ]D4.1.12 (HL)—Types of selection

Practice this topic

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

Coverage 2012–2025 · Updated 16 Jul 2026