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The Beauty of Kettlewell's Classic Experimental Demonstration of Natural Selection

Abstract H. B. D. Kettlewell's work on the phenomenon of industrial melanism is widely regarded as the classic demonstration of natural selection and one of the most beautiful experiments in evolutionary biology. The following essay discusses the mark–release–recapture experiments Kettlewell conducted in 1953 and 1955, with reference to Robert Crease's analysis of what it means for an experiment to be considered beautiful (significance of results, overall conceptual simplicity, conclusiveness). In fact, much of the apparent beauty of these experiments is illusory: the phenomenon of industrial melanism and Kettlewell's work on it are much more complicated than they are usually depicted in textbooks and the popular media. These complexities do not undermine the continued use of Kettlewell's work in science teaching, but they do suggest that the very features that lead scientists to appreciate Kettlewell's experiments as “beautiful” may be largely an artifact of how they have been portrayed.