CourseCourse QuestionQuestion

IB Environmental Systems and Societies

Topic 1: Foundation

Topic 2: Ecology

2.1 Individuals, populations, communities, and ecosystems

2.2 Energy and biomass in ecosystems

2.3 Biogeochemical cycles

2.4 Climate and biomes

2.5 Zonation, succession and change

2.5.1—Zonation definition

2.5.2—Transect use

2.5.3—Succession definition

2.5.4—Seral communities

2.5.5—Primary succession

2.5.6—Secondary succession

2.5.7—Succession changes over time

2.5.8—Ecosystem disturbance tolerance

2.5.9 (HL)—Community development influences

2.5.10 (HL)—Productivity patterns in succession

2.5.11 (HL)—r- and K-strategist species

2.5.12 (HL)—Climax community concept

2.5.13 (HL)—Plagioclimax

Topic 3: Biodiversity and conservation

Topic 6: Atmosphere and climate change

Topic 7: Natural resources

Topic 8: Human populations and urban systems

IB/ESS/HL//Concept/Topic 2: Ecology/2.5 Zonation, succession and change/2.5.6—Secondary succession

Topic 2: Ecology

Syllabus: First assessment 2026
Section: —
Level: HL

Exam analysis

Most tested topics

Individuals, populations, communities, and ecosystems
Energy and biomass in ecosystems
Biogeochemical cycles
Climate and biomes
Zonation, succession and change