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 appearing36%of analysed past papers

Latest appearanceNovember 2025

Most common paperPaper2

Most tested objectives

D4.1.1—Natural selection as mechanism32 questions
D4.1.2—Roles of mutation and sexual reproduction13 questions
D4.1.12 (HL)—Types of selection11 questions

Common question formats

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

Exam question appearances

November 2025Paper2 ["SL"] · TZ36(c)[ 7 ]D4.1.1—Natural selection as mechanism

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

Practice this topic

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

Coverage 2010–2025 · Updated 16 Jul 2026