CBSE Class 12 Biology – Evolution

Chapter Overview

Evolution explains how organisms change over generations through heritable traits. This chapter covers theories of life's origin, Darwin’s natural selection, mechanisms of evolution, evidences from fossils and comparative anatomy, and patterns like speciation and adaptive radiation. :contentReference[oaicite:0]{index=0}

Important Keywords

• Evolution: Genetic changes in populations over generations. :contentReference[oaicite:1]{index=1}
• Natural Selection: Differential survival based on heritable traits. :contentReference[oaicite:2]{index=2}
• Speciation: Formation of new species via divergent evolution.
• Adaptive Radiation: Rapid diversification of species into new niches (e.g., Darwin’s finches). :contentReference[oaicite:3]{index=3}
• Homology & Analogy: Traits from common ancestry vs similar function.
• Genetic Drift: Random allele frequency changes (e.g., founder effect). :contentReference[oaicite:4]{index=4}
• Mutation: Source of genetic variation. :contentReference[oaicite:5]{index=5}
• Hardy-Weinberg Principle: Genetic equilibrium model (p² + 2pq + q² = 1). :contentReference[oaicite:6]{index=6}