Peppered moths are found in two colors: black and white. What did Kettlewell demonstrate concerning the relationship between peppered moth populations and tree coloration? (Note that during that period, urban areas in England primarily used coal for heating.)
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- During the period when Kettlewell conducted his research in England, there was a demonstration of a correlation between the color variations of peppered moths and the change in tree coloration caused by industrial pollution, particularly from the use of coal in urban areas.
- Prior to industrialization, peppered moths were typically found in lighter or speckled coloration, which provided camouflage against light-colored tree bark, such as birch trees. However, with the onset of the Industrial Revolution and the widespread use of coal in urban areas, the tree bark in these regions became darker due to soot and pollutants, causing the trees to darken.
- As a result of the change in the environment, the darker, soot-covered tree trunks became more prevalent in polluted industrial areas. This change in tree coloration provided better camouflage for darker-colored (melanic) variants of the peppered moth. The darker moths had better survival rates on the darker tree bark, as they were less visible to predators, while the lighter-colored moths stood out more prominently against the darkened trees, making them more vulnerable to predation.
- Kettlewell's classic experiments, notably using peppered moths in both light and dark color variations, supported this phenomenon of natural selection. His work provided compelling evidence illustrating how changes in the environment, such as industrial pollution leading to altered tree bark coloration, resulted in a shift in the frequency of color variations within the peppered moth population. This change was attributed to the selective pressures exerted by predation, demonstrating the impact of environmental changes on the adaptation and survival of a species.