IB Biology HL · 2025
Unit 1: Unity and diversity
75 past paper questions from 8 papers across 2 exam sessions. See what repeats, then practise the same skills with AI marking.
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HL archive · 2025 to 2026
Unit 1: Unity and diversity
Latest exam session: May 2026
- questions
- 75
- questions
- papers
- 8
- papers
- exam sessions
- 2
- exam sessions
- micro-topics
- 31
Topics in Unit 1: Unity and diversity
In syllabus order. The ring is the share of the marks each one carries.
1.1
Water
8% of marks10 of the 125 marks across the 8 Biology HL papers analysed (8%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 6 questions
1.2
Nucleic acids
18% of marks22 of the 125 marks across the 8 Biology HL papers analysed (18%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 15 questions
1.3
Origins of cells
2% of marks2 of the 125 marks across the 8 Biology HL papers analysed (2%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 2 questions
1.4
Cell structure
12% of marks15 of the 125 marks across the 8 Biology HL papers analysed (12%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 9 questions
1.5
Viruses
11% of marks14 of the 125 marks across the 8 Biology HL papers analysed (11%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 10 questions
1.6
Diversity of organisms
2% of marks3 of the 125 marks across the 8 Biology HL papers analysed (2%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 3 questions
1.7
Classification and cladistics
22% of marks28 of the 125 marks across the 8 Biology HL papers analysed (22%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 11 questions
1.8
Evolution and speciation
14% of marks18 of the 125 marks across the 8 Biology HL papers analysed (14%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 10 questions
1.9
Conservation of biodiversity
10% of marks13 of the 125 marks across the 8 Biology HL papers analysed (10%) were on this topic. A past-paper pattern, not a guarantee for your next paper. · 9 questions
Exam pattern
How often each micro-topic has been examined, year by year. Each label is explained under the grid.
Does it repeat?
Top 4 of 31 micro-topics for the next sitting. Numbers are questions per year.
fewermore
| Micro-topic | 2025 | 2026 |
|---|---|---|
| 4Molecular evidence and the molecular clock, 2025: 4 questions | 1Molecular evidence and the molecular clock, 2026: 1 question | |
| 5Nucleotides & DNA vs RNA, 2025: 5 questions | 3Nucleotides & DNA vs RNA, 2026: 3 questions | |
| 4Speciation and reproductive isolation, 2025: 4 questions | 1Speciation and reproductive isolation, 2026: 1 question | |
| 4Evidence for evolution, 2025: 4 questions | ·Evidence for evolution, 2026: 0 questions |
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Questions on Unit 1: Unity and diversity, by exam session
Which papers asked about Unit 1: Unity and diversity, and which question numbers. Open a paper to see them highlighted.
May 2026
9 questions across 2 papers
May 2025
35 questions across 6 papers
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Frequently asked questions
Short answers about this page.
Which Biology HL exam sessions are covered for Unit 1: Unity and diversity?
2 exam sessions from 2025 to 2026, the latest May 2026. Every Paper 1 and 2 in every timezone is read and classified in full, which gives 8 papers in this archive.
Which Unit 1: Unity and diversity topic comes up most?
Molecular evidence and the molecular clock (1.7.3): in 63% of papers, last seen May 26 P1 TZA. Usually "identify", worth about 2.2 marks in a paper that includes it.
Can I see the original question and mark scheme?
No. The wording belongs to the IB. You get the citation, the marks, the command term and the skill tested, plus our own matched practice questions with worked answers and AI marking.
What do "banker", "due" and "rising" mean?
Banker: examined in at least one sitting in four and still appearing. Due: regular before, but absent for the last two exam sessions. Rising: clearly more common in the last two years. Our classification of real papers, not an IB statistic.
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