A3.1 Diversity of organisms

Diversity of organisms links variation, species concepts, classification tools, chromosome evidence, and genome comparisons to explain biological similarity and difference.

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 A3.1 Diversity of organisms appears across past papers.

Chance of appearing33%of analysed past papers

Latest appearanceNovember 2025

Most common paperPaper2

Most tested objectives

A3.1.7—Karyotyping and karyograms36 questions
A3.1.2—Species as groups with shared traits15 questions
A3.1.3—Binomial system14 questions

Common question formats

Data analysis
Definition or recall
Process explanation
Structured response
Diagram interpretation
Calculation
Comparison
Evaluation
Graph interpretation
Case study
Essay response
Extended response
Experimental design

Exam question appearances

November 2025Paper2 ["HL"] · TZ37(c)[ 1 ]A3.1.12 (HL)—Difficulties with biological species concept

November 2025Paper2 ["HL"] · TZ17(c)[ 4 ]A3.1.13 (HL)—Chromosome number as shared trait

November 2025Paper1A ["HL"] · TZ322[ 1 ]A3.1.8—Unity and diversity of genomes within species

November 2025Paper1A ["SL"] · TZ113[ 1 ]A3.1.3—Binomial system

November 2025Paper1A ["SL"] · TZ313[ 1 ]A3.1.4—Biological species concept

Practice this topic

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

Coverage 2010–2025 · Updated 15 Jul 2026