THEME A:  Unity and Diversity

The biology course is organized by theme.  Both standard level (SL) students and higher level (HL) students study the four themes at four levels of biological organization (molecules, cells, organisms and ecosystems).  HL students study some of these topics to greater depth. 

Theme A is Unity and Diversity.  

A1: Unity and Diversity of Molecules​

A1.1 Water
Quizlet study set for this topic

A1.2 Nucleic Acids
Quizlet study set for this topic​

A2: Unity and Diversity of Cells

A2.1 Origins of Cells (HL only)

A2.2 Cell Structure

A2.3 Viruses  (HL only)

A3: Unity and Diversity of Organisms

​A3.1 Diversity of Organisms
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A3.2 Classification and Cladistics  (HL only)

A4: Unity and Diversity of Ecosystems

A4.1 Evolution and Speciation

​A4.2 Conservation of Biodiversity