IB Biology Syllabus (2025): Overview and Objectives

Biology, as one of the natural sciences in the IB Diploma Programme, is fundamentally concerned with the study of life and living systems. Through a combination of conceptual learning and experimental investigation, the course encourages students to explore the complexity, diversity, and interconnectedness of life on Earth.

Scientific inquiry is at the core of the learning experience in IB Biology. Students are guided through the process of formulating research questions, designing and conducting experiments, collecting and analysing data, and evaluating scientific evidence. This hands-on approach develops not only practical laboratory skills but also critical thinking, collaboration, and scientific communication.

Throughout the course, students engage with relevant and often urgent global issues - such as climate change, genetic technology, biodiversity loss, and human health - helping them to recognize the impact of biology on their lives and the world around them. By examining knowledge claims and exploring ethical dimensions of scientific advancement, students also develop an understanding of the nature of science and its role in society.

The study of IB Biology fosters curiosity and responsibility, equipping students with the skills necessary for participation in an increasingly complex and interconnected world.

IB Biology Syllabus Content

Syllabus component	Recommended teaching hours
	SL	HL
Syllabus content
Unity and diversity Water Nucleic acids Origins of cells * Cell structure Viruses * Diversity of organisms Classification and cladistics * Evolution and speciation Conservation of biodiversity	19	33
Form and function Carbohydrates and lipids Proteins Membranes and membrane transport Organelles and compartmentalization Cell specialization Gas exchange Transport Muscle and motility * Adaptation to environment Ecological niches	26	39
Interaction and interdependence Enzymes and metabolism Cell respiration Photosynthesis Chemical signalling * Neural signalling Integration of body systems Defence against disease Populations and communities Transfer of energy and matter	31	48
Continuity and change 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	34	60
Experimental programme
Practical work	20	40
Collaborative sciences project	10	10
Scientific investigation	10	10

* Topics with content that should only be taught to HL students

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