It has been the accepted view among evolutionary biologists since Darwin published his Origin of Species in 1859 that measurable evolutionary changes occur slowly, often taking hundreds of generations. This view may now be about to change.
Pygmy grasshoppers exist in many different color variants and in many types of environment. Through a series of experiments and studies in nature, Magnus Karlsson discovered that the distribution between the color variants of pygmy grasshoppers differs across different environments. In recently burnt over areas, a very high proportion of the grasshoppers are black. In unburnt areas, on the other hand, the black variant is unusual. What's more, the proportion of black grasshoppers changes very rapidly between generations in the burnt areas, whereas the proportion in unburnt areas remains the same over the same period of time.
Magnus Karlsson presents data that show that the pygmy grasshoppers' color changes by natural selection. He believes that the primary cause of these changes is birds and other animals that hunt using their vision. The black grasshoppers are simply less visible against the burnt background,
"But the most important part of the dissertation is that I have shown that evolution sometimes proceeds incredibly rapidly. This is huge," says Magnus Karlsson.
His dissertation is titled Evolution in Changing Environments Revealed by Fire Melanism in Pygmy Grasshoppers.
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