The Peppered Moth

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The Peppered Moth

• Example of Evolution

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Background Information

• 1850s Industrial Revolution
• Moths (Biston betularia) come in both light and
  dark colors.
• Until the 1850s, the dark color was rare.
• After almost 100 years, the darker color was the
  dominant form.
• Birds are predators of moths

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What is happening?

• Hypothesis Evolution by natural selection is
  taking place in peppered moths.
• In polluted areas, dark moths have higher fitness
  (blend in with soot-covered trees) than light
  moths.
• In non-polluted areas, light moths have higher
  fitness.

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What is driving this evolution?

• Selective Pressure Predators
• Selective Agent BIRDS!
• Therefore, moths that blend in with trees have a
  higher fitness (survive to reproduce) than those
  that do not.

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The Moths
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Conclusion about the moths

• Due to natural selection, in polluted areas
  darker moths have a higher fitness.