[Campbell Biology P.535] Which evolutionary mechanism is best described by 'By chance alone,... | Practice Question

Which evolutionary mechanism is best described by 'By chance alone, alleles encoding darker color have become more common over several generations.' as depicted in the diagram showing beetle populations?

  • A: Natural Selection
  • B: Genetic Drift
  • C: Gene Flow
  • D: Mutation

Explanation

Genetic drift refers to random fluctuations in allele frequencies from one generation to the next, often by chance events. The description explicitly mentions 'by chance alone', which is characteristic of genetic drift, as opposed to natural selection differential survival/reproduction based on traits , gene flow migration , or mutation creation of new alleles .