IB · Biology

IB Diploma Biology

Explore life through four connected themes and four levels of organization, then choose SL or HL for the correct syllabus and resources.

Four themes across four scales of life

IB Biology explores life from molecules and cells to organisms and ecosystems through Form and function, Unity and diversity, Continuity and change, and Interaction and interdependence.

SL and HL share this conceptual structure, while HL develops the course with greater breadth and depth. Exact papers, marks and syllabus scope stay on the selected level page.

Choose a level to open study resources

Question Bank, Mastery, Concept and Documents links become available after SL or HL is selected.

Choose your Biology level

Select SL or HL before opening level-specific assessment, syllabus and study resources.

IB Biology questions

This page follows the IB Biology guide for first assessment in 2025.

Both levels use the same four themes and organizational scales, while HL develops greater breadth and depth.

Yes. Both levels include a scientific investigation; its exact weighting and the paper details are shown on the selected level page.

The levels have different paper durations, marks and syllabus depth, so a level is required before opening assessment details or resources.