Published in Milenio Diario, April 1, 2009
In 1837, returning from his five-year travel on board of theHMS Beagle, and starting the two decades he would spend thinking about the "transmutation of species", Charles Darwin wrote in his notebook the phrase "I think", and then he drew a little branched outline: the first evolutionary tree.
In 1859 he published The origin of species, and the only illustration he included was a more elaborate tree. Since then, the tree is evolution's dominant metaphor: a ramified process in which new species appear from pre-existent ones.
And of course, there are a lot of aspects in which
Recently, New Scientist magazine published an article that caused an upstir, because it declared that the discovery of "horizontal gene transfer" (not from parents to descendants, but like that which occurs when two bacteria exchange antibiotic resistance genes, or when a virus injects genes from another species into us, as has happened lots of times in human evolution) is the downfall of the image of evolution as a tree.
But gene evolution is not the same as species evolution. Of course, evolution is not as simple as
Maybe the tree metaphor will change, or will be substituted by a web. But from that to proclaiming "the end of
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