13–20% of the AP exam. Key topics: Evidence for evolution: fossil record, comparative anatomy (homologous, analogous, vestigial structures), molecular homology, biogeography, Mechanisms of natural selection: heritable variation, differential reproductive success, adaptation, Types of natural selection: directional, stabilizing, disruptive (diversifying), Other evolutionary mechanisms: genetic drift (bottleneck and founder effects), gene flow, mutation, Hardy-Weinberg equilibrium: conditions (large population, random mating, no mutation/migration/selection) and allele/genotype frequency calculations, Hardy-Weinberg as a null model — deviation from equilibrium indicates evolution, Speciation: allopatric vs. sympatric speciation; pre- and post-zygotic reproductive isolation mechanisms, Phylogenetics: constructing and interpreting cladograms, parsimony principle, shared derived characters (synapomorphies), Molecular clocks and evidence from DNA/protein sequence comparisons.
Study guide content for this unit is being prepared. Check back soon for complete lesson notes, formula sheets, and worked examples.
