IB Biology Syllabus Update - First Assessment 2025

We are pleased to announce that at SME, we're supporting the newly restructured IBDP Biology Course with a range of new updated resources including Revision Notes, Topic Questions and Model answers written and designed by experienced teachers.

Stewart Hird

Written by: Stewart Hird

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The New IB Biology Curriculum

The IBDP has an exciting new science curriculum for first teaching in September 2023 and first assessment in May 2025. The four Options examined in Paper 3 have been scrapped and some of the content has been incorporated in the new curriculum.

The new DP Biology course has undergone a radical overhaul in approach and has been constructed to promote concept-based teaching and learning. Read about it in the Biology Subject Brief.

There are four overarching themes, each comprising of two concepts:

Theme A: Unity and diversity

Theme B: Form and function

Theme C: Interaction and interdependence

Theme D: Continuity and change

These themes are divided into four levels of biological organisation covering 40 topics and subtopics headed by guiding questions. Linking questions are used to facilitate connections between different parts of the course to promote a highly networked understanding of biology.

IB Biology Syllabus Outline from 2023

Syllabus component

Teaching hours

SL

HL

 Syllabus content

110

180

 A: Unity and diversity

19

26

31

34

33

39

48

60

 B: Form and function

 C: Interaction and interdependence

 D: Continuity and change

 Experimental programme

40

60

 Practical work

20

10

10

40

10

10

 Collaborative sciences project

 Scientific investigation

 Total teaching hours

150

240

Study Skills in Biology

The skills and techniques students must experience through the course are encompassed within the tools: Experimental Techniques, Technology and Mathematics. These support the application and development of the inquiry process in the delivery of the biology course: Exploring & Designing, Collecting & Processing Data, and Concluding & Evaluating.

kKLeObKo_ib-chemistry-2025-skills

Source: ibo.org

What Will the New IB Biology Exams Look Like?

Students will have to take two external exams made up from the following components:

IB Biology SL Assessment Components 2025

 Assessment component  

Weighting

 External assessment (3 hours)

80%

 Paper 1 (1 hour and 30 minutes)

 Paper 1A—Multiple-choice questions

 Paper 1B—Data-based questions (four questions that are syllabus related, addressing all
themes)

 (Total 55 marks)

36%

 

 Paper 2 (1 hour and 30 minutes)

 Section A—Data-based and short answer questions
 Section B—Extended-response questions

 (Total 50 marks)

44%

 

 Internal assessment (10 hours)

20%

 The internal assessment consists of one task: the scientific investigation.

 This component is internally assessed by the teacher and externally moderated by the IB at the end of the course.

 (Total 24 marks)

 

 

IB Biology HL Assessment Components 2025

 Assessment component  

Weighting

 External assessment (4 hours 30 minutes

80%

 Paper 1 (2 hours)

 Paper 1A—Multiple-choice questions

 Paper 1B—Data-based questions (four questions that are syllabus related, addressing all
themes)

 (Total 75 marks)

36%

 

 Paper 2 (2 hours and 30 minutes)

 Section A—Data-based and short answer questions
 Section B—Extended-response questions

 (Total 80 marks)

44%

 

 Internal assessment (10 hours)

20%

 The internal assessment consists of one task: the scientific investigation.

 This component is internally assessed by the teacher and externally moderated by the IB at the end of the course.

 (Total 24 marks)

 

  

Comparing the 2014 syllabus with the 2023 syllabus 

  • Options have been removed and some parts of the previous options are now integrated into the new syllabus. As a result, Paper 3 is no more. 

  • However, it is worth noting, the IB did not just move all the option material into he core and AHL. It was a very select process looking at how a topic or subtopic now could blend in with one of the new core or AHL syllabus. 

  • The syllabus is less content-heavy (about 5% less). 

  • There is an emphasis on linking questions - teachers and students are encouraged to make links between topics.

  • There are changes in the assessment - since there now is no Paper 3, they have had to revamp papers 1 and 2 slightly. 

  • Paper 1 now has 2 parts- 1A is multiple choice and 1B consists of data-based questions, questions on lab skills, scientific methods, and more.

  • Paper 2 is very similar to the previous paper 2, but slightly longer. For example, now it is 2 hours 30 minutes in HL, and 80 marks.

  • There is still the same total number of hours students are sitting the exam, but it is now redistributed over 2 papers instead of 3.

  • The 'Group 4 Project', is now called the 'Collaborative Science Project'.

  • The 'Internal Assessment' is now the 'Scientific Investigation' and students can sometimes use data collected in group work on field trips (although each student's research question has to be different).

  • There are now 4 criteria, each equally weighted at 6 marks each (for a total of 24 marks): research design, data analysis, conclusion, and evaluation.

  • In terms of the syllabus roadmap, teachers can choose what sequence works for them. One of the inconvenient aspects of the roadmap version, is sometimes a topic or an idea will be introduced before that topic has been fully given in a future chapter, so sometimes it is better to jump ahead and then come back to the previous part of the roadmap. Therefore it is recommended not to completely teach it in order, although this depends on the teacher and what works for them. 

 

New Materials to Help You Study IB Biology

We are updating all our resources for the new IB course so that whether you are a student or a teacher, you can depend on them for high quality learning and revision - perfect for acing those exams!

example-resources-for-new-ib-biology

In the meantime, browse our existing IB Biology revision resources.

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Stewart Hird

Author: Stewart Hird

Expertise: Chemistry Lead

Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.

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