THEME D:  Continuity and Change

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 D is Continuity and Change

D1:  Continuity and Change of Molecules​

D1.1 DNA Replication

D1.2 Protein Synthesis

D1.3 Mutations and Gene Editing

D2:  Continuity and Change of Cells

D2.1 Cell and Nuclear Division

D2.2 Gene Expression (HL only)

D2.3  Water Potential

D3:  Continuity and Change of Organisms

D3.1 Reproduction

D3.2 Inheritance

D3.3 Homeostasis

D4:  Continuity and Change of Ecosystems

D4.1 Natural Selection

D4.2 Stability and Change

D4.3 Climate Change