As one reflects on this story, one realizes how fortunate we were to have acquired these mutations. Extinction is a common event. There have been at least five massive extinctions that each led to the demise of more than 50 percent of species living at that time.38 Recall that during the Miocene there were 100 different ape species, for which only 5 survive today.39 Consider the fact only Homo sapiens survive today, and related species in our genus, such as Home erectus, Homo antecessor, Homo heidelbergensis and Neanderthals (Homo neanderthalensis) no longer walk the earth. We are lucky to be
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