A3.1.14 (HL)—Dichotomous key development
Dichotomous keys identify organisms through paired observable choices that separate groups step by step until one taxon or specimen remains.
- Syllabus
- First assessment 2025
- Objective
- A3.1.14
- Level
- HL
Exam analysis
Chance of appearing1%of analysed past papers
Latest appearanceMay 2014
Most common paperPaper2
Typical marks1
Common command terms
- Identify
Scoring notes
- Common mistake
- Choosing an organism from appearance alone instead of following each key branch.
Recent exam appearances
May 2014Paper2 ["HL"] · TZ23(a)[ 1 ]A3.1.14 (HL)—Dichotomous key development
Practice this objective
Coverage 2014–2014 · Updated 15 Jul 2026
Concept essentials
- Dichotomous keys use paired contrasting choices.
- Each answer in a key leads to another choice or a final identification.
- Useful key characters must be observable and able to separate organisms clearly.
- Constructing a key requires comparing organisms feature by feature.