Welcome to IB Biology 2025
Master the new syllabus structure with our comprehensive study tools. The 2025 curriculum is organized around four key themes that connect biological concepts across different levels of organization.
Theme A: Unity & Diversity
Common ancestry has given living organisms many shared features while evolution has resulted in the rich biodiversity of life on Earth
Theme B: Form & Function
Adaptations are forms that correspond to function. These adaptations persist from generation to generation because they increase the chances of survival
Theme C: Interaction & Interdependence
Systems are based on interactions, interdependence and integration of components. Systems result in emergence of new properties at each level of biological organization
Theme D: Continuity & Change
Living things have mechanisms for maintaining equilibrium and for bringing about transformation. Environmental change is a driver of evolution by natural selection
Study Modes
Your Progress
Command Terms Reference
Understanding command terms is crucial for exam success. Each term tells you exactly what type of response is expected.
Assessment Objective 1: Demonstrate Knowledge and Understanding
Assessment Objective 2: Apply Knowledge and Understanding
Assessment Objective 3: Construct, Analyze and Evaluate
MCQ Practice
Free Response Practice
Study Tools
Exam Techniques
Data Analysis Steps
MCQ Strategies
Free Response Tips
Key Terminology
Assessment Structure
Paper 1
Format: Multiple choice questions and data-based questions
Duration: SL: 1.5 hours, HL: 2 hours
Weighting: 36%
Section 1A: 30 MCQ (SL) / 40 MCQ (HL)
Section 1B: 4 data-based questions related to experimental work and syllabus
Paper 2
Format: Data-based questions and extended response
Duration: SL: 1.5 hours, HL: 2.5 hours
Weighting: 44%
Section 2A: Data-based questions from unfamiliar contexts and short-answer questions
Section 2B: Extended-response questions focusing on holistic knowledge