Evolution and speciation explain how heritable variation, molecular evidence, selection, isolation, and chromosome change produce population divergence and new species over time.
Coverage 2010–2025 · Updated 15 Jul 2026
• Evolution is cumulative change in heritable characteristics of a population
• Acquired characteristics are not inherited in the Darwinian sense
• Universal DNA, genetic code, ATP use, and core metabolism support common ancestry
• DNA, RNA, and protein sequence differences indicate relatedness and divergence
• Selective breeding shows traits can change rapidly under selection
• Examples include pigeons, domesticated animals, Brassica crops, wheat, and maize
• Homologous structures share ancestry even when functions differ
• Vertebrate pentadactyl limbs support divergent evolution and adaptive radiation
• Analogous structures have similar functions but different evolutionary origins
• Similar selection pressures can produce convergence, such as bat and insect wings
• Speciation forms new species by splitting a pre-existing species
• Isolated gene pools diverge through selection, mutation, and genetic drift
• Reproductive isolation reduces gene flow so populations can diverge
• Geographic separation and different selection pressures can drive speciation
• Chimpanzees and bonobos illustrate river-linked isolation and divergence
