Practice question

Industrial melanism in peppered moth Biston betularia shows directional selection favoring dark morph in soot-polluted forests due to improved camouflage from bird predation. Kettlewell's experiments measured selection coefficients. With clean air acts, light morph recovered. This classic example demonstrates natural selection acting on existing variation in response to human-induced environmental change. Therefore it exemplifies Directional selection driving rapid adaptive shift. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype and environment.