Jonathan Wells, Ph.D. Department of Molecular Cell Biology University of California Berkeley, California, USAEvery student of biological evolution learns about peppered moths. The dramatic increase in dark forms of this species during the industrial revolution, and experiments pointing to differential bird predation as the cause, have become the classical story of evolution by natural selection. The same careful scientific approach which established the classical story in the first place, however, has now revealed major flaws in it. It is time to take another look.The peppered moth, Biston betularia, comes in various shades of gray. One hundred and fifty years ago,...