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A4.2.5—Evidence for biodiversity crisis

Evidence for the biodiversity crisis comes from repeated surveys, diversity indices, global assessments, and validated observations across disturbed and undisturbed habitats.

Syllabus
First assessment 2025
Objective
A4.2.5
Level
HL

Concept essentials

  • Repeated surveys are needed to detect biodiversity change rather than one-off variation.
  • Richness, evenness and diversity indices provide quantitative evidence of community change.
  • Global assessments synthesize many studies to evaluate extinction and habitat-loss trends.
  • Citizen science can support biodiversity evidence when records are verified and sampling bias is considered.
ConceptIB Biology HL