In the 1920's Heslop Harrison thought that pollution was causing mutations in the moths making them dark. Harrison decided to test his idea by conducting experiments with moths. He claimed that feeding polluted leaves to larvae darkened the moths. He didn't use peppered moths. He used similar moths that like peppered moths appear as light and dark colored moths. When the pupae (caterpillars) were fed leaves coated with coal soot the wings of the adults were darker.
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ASL Harrison concluded that the darker moths were a result of pollution induced mutations in the moths, not natural selection.
Other scientists tried to replicate Harrison's experiments using peppered moths. They didn't get the same results. In their experiments the moths didn't get darker. A few scientists have breed peppered moths for their experiments. They cross light and dark moths. The next generation fit the same pattern Mendel found with his peas. One gene controls whether the moth is light or dark. The dark form "A" is dominant and the light form "a" is recessiveIs it possible that both Harrison and the other scientists honestly reported their experiments?
A few gray peppered moths have been reported. These rare gray moths are almost never seen in the industrial areas. Scientists don't consider these gray moths relevant.
Scientists rejected Harrison's idea that pollution caused frequent mutations turning the peppered moths dark. As scientist you need to ask, "What part or part(s) of Harrison's idea were wrong?" Scientists don't want to, "Throw out the baby with the bath water."
Peppered Moths Mutation theory
Edited by OliverChant, : Forgot to put website name