HL Topic 3.2 extends evolutionary theory with more detailed analysis of genetic variation mechanisms, speciation pathways, and the evidence for evolution. Students evaluate case studies of adaptive radiation, co-evolution, and the genetic basis of natural selection.
Key Idea: Biodiversity exists because species change over time. This is called {{evolution|Gradual change in inherited traits over generations.}} — it's why we have so many different species!
Always use this order: variation → selection → reproduction → inheritance
Evolution happens to populations, not individuals. Nature picks what survives, not what's "best".
At Higher Level, ESS includes an extended essay component and deeper analytical questioning. Expect longer data-response questions and more complex case study scenarios in both Paper 1 and Paper 2.
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Start studying freeTopic 3.2 Natural selection, variation and speciation forms a core part of Unit 3: Biodiversity and Conservation in IB ESS HL. Mastering these concepts will strengthen your understanding of connected topics across the syllabus and prepare you for exam questions that require analysis, evaluation, and real-world application.
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