Practice question

Stabilizing selection reduces phenotypic variance by favoring intermediate trait values and selecting against extremes, common in stable environments where intermediate optimum has highest fitness, such as human birth weight where very low or high weights increase mortality. It maintains adaptation, reduces genetic variation and preserves mean. Over time distribution narrows. Hence it favors Constant environment, contrasting with directional and disruptive modes that shift or split mean. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links between genotype, phenotype and environment.