Kettlewell, Henry Bernard Davis
(1907–79) British lepidopterist and geneticist: experimented to confirm Darwin’s theory of natural selection.
A medical graduate who practised in England and worked on locust control in South Africa, Kettlewell’s best-known work was done as an Oxford geneticist in the 1950s. He noted that many species of peppered moth that in the mid-19th-c were light in colour had became dark by the 1950s. He deduced that the darkening (melanism) was related to the darkening of the tree stems on which the moths remained by day, by industrial smoke. This would cause dark forms to survive predation by birds more successfully. To test his idea, he released light and dark forms of one moth ( Biston betularia ) in large numbers in both a polluted wood near Birmingham and an unpolluted wood. Recapture of many of the moths after an interval confirmed that the light form survived best in the unpolluted wood and the converse in the Birmingham wood. This result, claimed to confirm Darwinism, was later seen to be statistically inadequate.
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