IB Biology Curriculum Overhaul: Key Updates for 2025

Introduction

The IBDP syllabus updates are significant as they reflect the changing needs of the global education landscape and prepare students for the challenges of the future. As such, it is crucial for students, parents, and educators to be aware of these updates and how they may impact the educational experience of IB students.

Starting from the May 2025 examination session, significant changes will be implemented to modernize and improve the curriculum. In this blog, we’ll delve into these updates, compare the old and new syllabi, and offer practical advice on how to prepare effectively for the revamped course.

The IB Biology syllabus is divided into five components: Unity and Diversity, Form and Function, Interaction and Interdependence, Continuity and Change, and Experimental Programme. The content covered under each component along with the IB recommended teaching hours can be found below.

IB Biology Curriculum Model Overview

Unity and Diversity consists of:

• Water
• Nucleic Acids
• Origins of cells
• Cell structure *
• Viruses * 
• Diversity of Organisms
• Classification
• Evolution and Speciation
• Conservation of biodiversity

Form and function consists of:

• Carbohydrates and lipids
• Proteins
• Membranes and transport
• Organelles
• Cell specialization
• Gas exchange
• Transport
• Muscle and motility
• Adaptation to environment 
• Ecological niches

Interaction and interdependence includes:

• Enzymes and metabolism
• Cell respiration
• Photosynthesis
• Chemical signaling *
• Neural signaling
• Integration of body systems
• Defense against disease
• Populations and communities
• Transfer of energy and matter

Finally, Continuity and change involves:

• DNA replication
• Protein synthesis
• Mutations and gene editing
• Cell and nuclear division
• Gene expression * 
• Water potential
• Reproduction
• Inheritance
• Homeostasis
• Natural selection
• Sustainability and change
• Climate change

* = HL Specific topics

The experimental programme involves practical work in the laboratory such as experiments on photosynthesis or the effect of light on photosynthesis as well as the Internal Assessment (IA) and Collaborative sciences project.

Speaking from experience, students that opt for the Biology course should also familiarize themselves with the assessment model and objectives as it helps in identifying key marking points and clearly describes to the student what is expected from the answer. This improves the chance of scoring maximum points for each question, making answers more apt and accurate.

IB Biology Assessment Model Overview

There are four assessment objectives for the DP biology course. Having followed the biology course, students are expected to demonstrate the following assessment objectives.

Assessment objective 1

Demonstrate knowledge of definitions, concepts, and techniques.

1. State two membrane-bound organelles present in this electron micrograph (2)
   
   1. State one organelle present in animal cells but not in plant cells (1)
   2. State one organelle that is common to both prokaryotic and eukaryotic cells (1)

These questions are commonly seen in Paper 2 for both SL and HL students.

Assessment objective 2

Understand and apply knowledge of terminologies and techniques to broader questions.

1. Discuss briefly whether the sound of bird chatter represents an example of innate and learned behaviour. (2)

These questions are seen at the end of a data-based question and require your knowledge on the topic as well as the data provided in the question.

Assessment objective 3

Analyze, evaluate, and synthesize experiments, trends, data, and patterns using evidence.

Such questions require you to highlight key trends and the effect of those trends on the results of the experiment. It also requires your critical thinking skills to identify weaknesses and improvements in the experiment. If you love research, you are sure to love these questions!

1. Calculate the difference in mean time spent studying squirrel-scented filter paper with and without rattlesnake scent. [1]
2. Outline the conclusions that can be drawn from the control results. [2]

Assessment objective 4

Demonstrate the application of skills necessary to carry out insightful and ethical investigations.

These questions often require you to construct experimental procedures using your previous knowledge. Identifying the correct apparatus, variables, and safety concerns will help you achieve the maximum marks.

Example Question: Describe an investigation procedure that can be used to determine limiting factors for photosynthesis in plants. (4 marks)

Key changes in the IB Biology syllabus 2025

1. External Assessments:

In the old assessment pattern, assessments consisted of three written papers, including multiple-choice questions, short answer questions, and extended response questions. However, while the core structure of written papers remains, the format has now been adjusted to include more data analysis and interpretation, reflecting the skills needed in modern scientific research.

Now, all students will now only sit two external examinations: Paper 1A includes multiple-choice questions on the syllabus and paper 1B includes data-based questions that are syllabus related, addressing all themes. SL students have 1.5 hours while HL students have 2 hours for this paper and is worth 36% of the total grade for both SL and HL.

Paper 2A includes data-based questions from unfamiliar contexts and short-answer questions. Paper 2B includes extended-response questions that focus on holistic knowledge and understanding of a wide range of syllabus content, skills, concepts and understandings. Once again, SL students have 1.5 hours for this exam while HL students have 2.5 hours for the same. The weightage of the final grade is 44% for this paper.

Other changes include the removal of the option topics (neurobiology and behavior, biotechnology and informatics, ecology and conservation and human physiology). This was initially Paper 3 attempted by all candidates under the old assessment pattern. Now, content from all four options has been incorporated into the core content of the course at the standard and higher level.

2. Curriculum content and syllabus

The previous syllabus was divided into six core topics and additional options that students could choose from. The core topics included:

• Cell Biology
• Molecular Biology
• Genetics
• Ecology
• Evolution and Biodiversity
• Human Physiology

while the additional options included Neurobiology, Biotechnology and Bioinformatics, Ecology and Conservation, and Human Physiology.

There is now an increased emphasis on systems thinking, the interconnections between topics, and real-world applications. New areas like bioinformatics, synthetic biology, and environmental sustainability are now also included.

3. Internal Assessments

The ‘scientific investigation’ (internal assessment) will also see a change, with the opportunity for students to collaborate and support each other within small groups. Where appropriate, students will be able to share similar methodologies, provided that the independent or dependent variables differ, and the data collected is unique to each student.

Students will continue to submit an individual report, with the outcome of the scientific investigation assessed through the form of a written report. The maximum overall word count for the report is 3,000 words rather than a page limit of 20 pages under the old syllabus. The revised criteria will place a greater emphasis on higher-order thinking skills with 50% of the marks allocated for Conclusion and Evaluation.

4. Group 4 collaborative project

The collaborative sciences project is an interdisciplinary sciences project that addresses real-world problems that can be explored through the range of subjects in the sciences group. In our opinion, it is a great way to involve all the disciplines of science to tackle problems that we see on a daily basis.

5. Skills development

The old syllabus emphasized traditional laboratory skills and theoretical understanding while the new syllabus has a greater focus on developing critical thinking, problem-solving, and research skills. There is a stronger emphasis on collaboration and communication, preparing students for the collaborative nature of modern science.

How to prepare for these changes

1. Understand the New Topics and Themes Early:

Bioinformatics: Begin by exploring basic bioinformatics tools and databases such as BLAST and GenBank. There are many free online resources and tutorials that can introduce you to these tools.

Synthetic Biology: Familiarize yourself with the principles of synthetic biology. Reading books like “Synthetic Biology: A Primer” and watching educational videos on platforms like Coursera can provide a solid foundation.

Environmental Sustainability: Engage with current research and case studies on environmental issues. Websites like the World Wildlife Fund (WWF) and scientific journals can provide in-depth information on the latest sustainability practices and challenges.

2. Develop Practical Skills with Advanced Techniques:

CRISPR and Genetic Engineering: Understand the basics of CRISPR and its applications in genetic engineering. There are many online simulations and tutorials available to help you get started.

Ecological Fieldwork: Participate in local ecological surveys or conservation projects. Practical experience in fieldwork will enhance your understanding of ecology and environmental biology.

Lab Techniques: Practice advanced lab techniques such as PCR, gel electrophoresis, and spectrophotometry. Many universities offer online lab simulation tools that can help you gain hands-on experience.

3. Utilize Digital Tools and Resources:

Virtual Labs: Use virtual lab simulations to practice experiments and reinforce your understanding of biological concepts. Websites like Labster offer interactive simulations that cover a wide range of topics in biology.

Data Analysis Software: Learn to use software like Excel, R, or Python for analyzing biological data. These tools are essential for interpreting experimental results and data analysis in the Biology IA. Statistical analyses like Chi-Square, T-Test, Regression are important tools that you should be familiar with.

4. Engage in Interdisciplinary Learning:

Biology and Chemistry: Study the intersection of biology and chemistry, such as biochemistry and molecular biology. Understanding these connections can provide deeper insights into biological processes.

Biology and Physics: Explore topics like biomechanics and biophysics. Understanding the physical principles underlying biological systems can enhance your comprehension of complex biological phenomena.

5. Focus on Real-World Applications and Case Studies:

Medical Case Studies: Analyze case studies related to human health and disease. Websites like the New England Journal of Medicine provide access to medical case studies that can help you understand the application of biological concepts in medicine.

Environmental Impact Studies: Investigate case studies on the impact of human activities on ecosystems. This will help you understand the relevance of ecology and environmental biology in addressing global challenges. This tip will also assist you in practicing and preparing for the data-based questions that many students find challenging!

6. Enhance Research Skills and Critical Thinking:

Literature Reviews: Conduct literature reviews on current biological research topics. This will help you develop the ability to critically evaluate scientific literature and stay updated with the latest advancements in biology.

Research Projects: Engage in independent or group research projects. Designing and conducting your own experiments will enhance your practical skills and deepen your understanding of the scientific method. Additionally, they will help you answer questions that require you to design experiments or have knowledge of how experiments work.

7. Regularly Review and Reflect on Learning:

Concept Maps: Create concept maps to visualize the connections between different topics. This will help you understand how different concepts in biology are interrelated.

Peer Discussions: Engage in discussions with your peers about complex topics. Explaining concepts to others and hearing different perspectives can reinforce your understanding and uncover areas that need further study.

8. Practice Past Papers with Updated Assessment Formats:

Data Analysis Questions: Practice answering data analysis and interpretation questions, which are emphasized in the new assessments. Use past papers and sample questions to get familiar with the types of questions you might encounter.

Extended Response Questions: Develop your ability to write clear and concise extended responses. Practice organizing your thoughts and structuring your answers logically.

Final Thoughts

The changes to the IB Biology course starting in 2025 represent an exciting evolution, aimed at making the curriculum more relevant and engaging for students. By understanding these changes and preparing effectively, you can make the most of your IB Biology experience and set yourself up for success in your future studies and career.

With the tips and techniques suggested by Tychr in this blog, you’ll be well-prepared to tackle the new IB Biology course with confidence. For personalized support, consider Tychr’s expert IB Biology SL tutors & IB Biology HL tutors. They provide tailored guidance, ensuring you master key concepts and excel in assessments. Stay curious, proactive, and dedicated to your learning, and you’ll be well-equipped to succeed in this challenging yet rewarding program.

Happy studying, and best of luck on your IB journey!