the mechanism Darwin described really does seem to be fundamental to the history of life. Let finches breed on one of the Galápagos Islands that Darwin visited in his youth. If this island’s trees produce nuts with tough shells, over time those finches with beaks that can crack the shells most efficiently will survive better and produce more offspring than others. Wait a few generations, and you will find all the finches on this island have this type of beak. Over time, as some individuals are selected by “nature” (in fact, by the rules of the local environment), a new species will eventually
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