IB ESS HL 2.5.7 Succession Changes Over Time Questions

Explain how vegetation, soil, food webs and species diversity change across successional stages using ecological evidence.

Syllabus
First assessment 2026
Course
ESS HL
Level
HL

Exam points

  • identify changes in vegetation cover or community composition over time during succession using figure evidence
  • explain how succession increases soil fertility and resilience through weathering, organic matter, decomposition, nutrient cycling, roots and soil development
  • outline how a food web changes during succession through additional species, trophic levels, branching, biomass, productivity and decomposer prominence
  • compare pioneer-stage and climax-stage soil quality, including organic matter, available minerals, organisms, nutrient cycling, vegetation cover and erosion risk
  • explain why species diversity changes between successional stages using habitat availability, productivity, nutrient cycling, richness and evenness

IB ESS HL 2.5.7 Succession Changes Over Time Questions question 1

[Maximum number: 2]
Distribution of birch forest in Iceland in 874 and 2015

Figure:Distribution of birch forest in Iceland in 874 and 2015

Soil erosion in Iceland in 2007

Figure:Soil erosion in Iceland in 2007

Stages of soil degradation and vegetation-cover change in Iceland

Figure:Stages of soil degradation and vegetation-cover change in Iceland

Known distribution of Nootka lupin in 2010

Figure:Known distribution of Nootka lupin in 2010

With reference to Figures: Distribution of birch forest in Iceland in 874 and 2015, Soil erosion in Iceland in 2007, Stages of soil degradation and vegetation-cover change in Iceland and Known distribution of Nootka lupin in 2010 identify two ways in which vegetation cover has changed over time in Iceland.

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