At a glance
- First assessed
- May 2025 (taught from August 2023)
- Structure
- 4 themes x 4 levels of organisation
- Paper 1
- 1A + 1B, 36%
- Paper 2
- 44%
- Internal assessment
- Scientific investigation, 20%
How the content is organised
Each theme is studied at each level of organisation. Examples below show the kind of content in each cell; your school's scheme of work gives the full list.
| Theme | Molecules and cells | Organisms and ecosystems |
|---|---|---|
| A: Unity and diversity | Water, nucleic acids, cell structure, viruses (HL) | Classification, evolution and speciation, conservation of biodiversity |
| B: Form and function | Carbohydrates, lipids and proteins; membranes and organelles | Gas exchange, transport, adaptation to environment, ecological niches |
| C: Interaction and interdependence | Enzymes and metabolism, cell respiration, photosynthesis, cell signalling | Integration of body systems, defence against disease, populations and communities, energy and matter transfers |
| D: Continuity and change | DNA replication, protein synthesis, mutation, cell and nuclear division | Reproduction, inheritance, homeostasis, natural selection, stability and change in ecosystems |
HL students study additional material within the same grid rather than a separate block of topics.
How it is examined
| Component | SL | HL | Weighting |
|---|---|---|---|
| Paper 1A: multiple choice | 30 questions | 40 questions | 36% with 1B |
| Paper 1B: data-based questions | 25 marks | 35 marks | 36% with 1A |
| Paper 1 total | 1 h 30 min, 55 marks | 2 h, 75 marks | 36% |
| Paper 2: data, short answer, extended response | 1 h 30 min, 50 marks | 2 h 30 min, 80 marks | 44% |
| Scientific investigation | About 10 hours, 24 marks | About 10 hours, 24 marks | 20% |
Papers 1A and 1B are sat together. At HL, Paper 2 Section B asks for two of three extended responses.
What actually changed, and why it matters
The old course had core topics, additional HL topics and one option studied in depth, examined in Paper 3. The new guide removes the options and Paper 3 and asks students to connect ideas across the grid. A single question can start with the structure of a molecule and end with a consequence for an ecosystem, so learning topics as separate chapters is less effective than before.
Data handling carries more weight. Paper 1B is entirely data-based questions, and Paper 2 opens with data analysis. Students who can read an unfamiliar graph, quote values with units, calculate a percentage change and link a trend to biology gain marks across both papers.
The internal assessment also changed. The old five-criterion rubric, which included personal engagement and communication, has been replaced by four criteria of 6 marks each: research design, data analysis, conclusion and evaluation. The guide also includes a collaborative sciences project; ask the school how it runs.
How to revise for the new papers
- Learn content level by level within each theme, then make links across: for example, from enzyme structure (molecules) to metabolism in cells to effects of temperature on organisms and ecosystems.
- Practise Paper 1B-style data questions weekly from DP1. Use specimen papers and papers from May 2025 onwards for full practice.
- Use older past papers selectively, for single-idea questions on content that is still in the guide. Skip option questions and anything that no longer appears.
- Write extended responses as distinct, correct points using precise vocabulary, since markschemes reward separate creditworthy ideas.
- Learn the command terms. "Outline", "explain", "evaluate" and "discuss" ask for different depths.
Common mistakes with the new course
- Revising from pre-2025 topic lists and spending time on option content that is no longer examined.
- Treating data questions as easy marks and not practising them, then losing time in Paper 1B.
- Describing a graph without quoting values, or explaining a trend without linking it to the biology.
- Leaving the extra HL material to DP2, which crowds the revision period.
How one-to-one lessons help with the new course
A tutor who teaches the current IB Biology guide follows the order your school teaches and uses each lesson for three things: securing the concept (often by drawing processes on the shared whiteboard), practising the matching data-based question, and building precise written answers that match markscheme language. For HL students, lessons regularly connect ideas across themes and levels, which the new papers reward.
Because old resources are everywhere, a tutor also acts as a filter, choosing practice that matches the current guide and setting aside material from the old options.
Common questions
Is there still a Paper 3 in IB Biology?
No. Since May 2025 the options and Paper 3 have been removed. Assessment is Paper 1 (1A and 1B), Paper 2 and the scientific investigation.
Are old IB Biology past papers still useful?
For single-idea practice on content that is still in the guide, yes. For full exam practice use specimen papers and papers from May 2025 onwards, which match the current format.
How is HL different from SL in the new guide?
HL has 240 teaching hours against 150 for SL, extra content within the same themes, and longer papers, for example Paper 2 is 2 hours 30 minutes at HL against 1 hour 30 minutes at SL.
When will the guide change again?
The IB reviews subjects on a cycle of several years. The current guide applies to students sitting exams now; check the IB's curriculum updates if your child starts DP1 several years from now.
How much do IB Biology lessons cost with LiveTutor?
$15 a lesson, the same flat rate for every subject and level, on a weekly plan of 1 to 5 lessons billed monthly. Lessons are 60 minutes, one to one and online, and the first lesson is a free trial.
Sources
Dates and figures on this page come from these official and published sources. Always confirm deadlines on the official page before acting on them.