Q57 / 200 · MHT CET - Medical 2026 (22 April Shift 2) · Biology

Industrial melanism observed in different species of moths is an example of ____.

  • A
    stabilizing selection
  • Correct answer
    B
    directional selection
  • C
    ecological isolation
  • D
    ethological isolation

Solution

Industrial melanism is a classic example of directional selection.

Before industrialization, light-coloured moths were more prevalent because they were well-camouflaged against the lichen-covered tree trunks, protecting them from predators. However, during industrialization, pollution killed the lichens and darkened the tree trunks with soot. This environmental change favoured the dark-coloured (melanic) moths, which were now better camouflaged. As a result, the population shifted in one specific direction towards the darker phenotype.

This shift in the frequency of a trait in a consistent direction in response to environmental changes is the defining characteristic of directional selection.

Answer: directional selection

Hence, the correct answer is option: 'B'.

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