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Evolution in action
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Evolution in action Peppered Moth (Biston betularia)
2 types: Speckled (white) and Melanic (dark) Peppered moth
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Evolution in action Year % dark % light 1848 5 95 1895 98 2 1995 19 81
clean air, light-coloured bark pollution, dark-coloured bark Clean Air Act, light-coloured bark industrial melanism
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Evolution in action Melanic and speckled moths on lichen-covered tree trunk. Can you even find the speckled moth?
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Melanic and speckled moths on soot-covered tree trunk
Evolution in action Melanic and speckled moths on soot-covered tree trunk
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Evolution in action Why did the population change?
early 1800s = pre-industrial England low pollution lichen on trees = light coloured bark Melanic gene selected OUT late 1800s = industrial revolution factories = soot/ash coated trees killed lichen = dark coloured bark Melanic gene selected IN mid 1900s = pollution controls clean air laws return of lichen = light coloured bark
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Survival of the Fittest
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