IB Diploma Programme Biology Higher Level
IB Diploma Programme Biology Higher Level (HL) is a rigorous 240-hour course structured around four unifying themes — Unity and Diversity, Form and Function, Interaction and Interdependence, and Continuity and Change — each explored at the molecular, cellular, organism, and ecosystem levels of organisation. HL students master 150 hours of shared SL content plus 90 hours of Additional Higher Level (AHL) material covering gene expression, chemical signalling, muscle physiology, origins of cells, classification and cladistics, and viruses, assessed through two written papers and an internal investigation (IA). The course is assessed on a 1–7 IB grade scale and is designed to prepare students for university studies in biological and health sciences.
Who Should Take This
Pre-university students (ages 16–19) enrolled in the IB Diploma Programme who intend to pursue higher education in biology, medicine, biomedical science, veterinary science, or related disciplines, and require a challenging, concept-driven science credential recognised by universities worldwide.
What's Covered
1Theme A: Unity and Diversity
2Theme B: Form and Function
3Theme C: Interaction and Interdependence
4Theme D: Continuity and Change
What's Included in AccelaStudy® AI
Course Outline
1Theme A: Unity and Diversity 4 topics
A1 — Molecules
- A1.1 Water
- A1.2 Nucleic Acids
A2 — Cells
- A2.2 Cell Structure
- A2.1 Origins of Cells (AHL)
- A2.3 Viruses (AHL)
A3 — Organisms
- A3.1 Diversity of Organisms
- A3.2 Classification and Cladistics (AHL)
A4 — Ecosystems
- A4.1 Evolution and Speciation
- A4.2 Conservation of Biodiversity
2Theme B: Form and Function 4 topics
B1 — Molecules
- B1.1 Carbohydrates and Lipids
- B1.2 Proteins
B2 — Cells
- B2.1 Membranes and Membrane Transport
- B2.2 Organelles and Compartmentalisation
- B2.3 Cell Specialisation
B3 — Organisms
- B3.1 Gas Exchange
- B3.2 Transport
- B3.3 Muscle and Motility (AHL)
B4 — Ecosystems
- B4.1 Adaptation to Environment
- B4.2 Ecological Niches
3Theme C: Interaction and Interdependence 4 topics
C1 — Molecules
- C1.1 Enzymes and Metabolism
- C1.2 Cell Respiration
- C1.3 Photosynthesis
C2 — Cells
- C2.1 Chemical Signalling (AHL)
- C2.2 Neural Signalling
C3 — Organisms
- C3.1 Integration of Body Systems
- C3.2 Defence Against Disease
C4 — Ecosystems
- C4.1 Populations and Communities
- C4.2 Transfers of Energy and Matter
4Theme D: Continuity and Change 4 topics
D1 — Molecules
- D1.1 DNA Replication
- D1.2 Protein Synthesis
- D1.3 Mutations and Gene Editing
D2 — Cells
- D2.1 Cell and Nuclear Division
- D2.2 Gene Expression (AHL)
- D2.3 Water Potential
D3 — Organisms
- D3.1 Reproduction
- D3.2 Inheritance
- D3.3 Homeostasis
D4 — Ecosystems
- D4.1 Natural Selection
- D4.2 Stability and Change
- D4.3 Climate Change
Scope
Included Topics
- Theme A: Unity and Diversity — water, nucleic acids, cell structure, origins of cells (AHL), viruses (AHL), diversity of organisms, classification and cladistics (AHL), evolution and speciation, conservation of biodiversity
- Theme B: Form and Function — carbohydrates, lipids and proteins, membranes and transport, organelles and compartmentalisation, cell specialisation, gas exchange, transport systems, muscle and motility (AHL), ecological niches and adaptation
- Theme C: Interaction and Interdependence — enzymes and metabolism, cell respiration, photosynthesis, chemical signalling (AHL), neural signalling, integration of body systems, defence against disease, populations and communities, energy and matter transfers
- Theme D: Continuity and Change — DNA replication, protein synthesis, mutations and gene editing, cell and nuclear division, gene expression (AHL), water potential, reproduction, inheritance, homeostasis, natural selection, ecosystem stability, climate change
- Internal Assessment (IA) — individual scientific investigation worth 20% of final grade
- Assessment Objectives AO1–AO4 — knowledge recall, application of concepts, analysis of data, and synthesis/evaluation across all themes
Not Covered
- Standard Level (SL) exclusive teaching hours and assessment differentiation
- IB Diploma Programme Theory of Knowledge (TOK) linkages and extended essay requirements
- Pre-2025 legacy syllabus optional topics (neurobiology and behaviour, biotechnology and bioinformatics, ecology and conservation, human physiology options)
- Laboratory practical manual and specific prescribed practicals not assessed in written papers
- Group 4 collaborative project assessment criteria and process
Official Exam Page
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