johnscanlon wrote

"Species CAN be paraphyletic because bits of them can bud off as new species which are then more closely related to some members than others in the 'parent' species."



Higher taxa also originate by the process of budding. In fact, it is extremely unlikely that splitting, in which an entire higher taxon becomes extinct when a new higher taxon evolves, is the norm in evolutionary history. A small genus with a few species may eventually become extinct, but large genera such as Hyla, Rana, and Bufo can persist for long periods of geological time and remain paraphyletic, since they are morphologically conservative and since morphologically divergent taxa have budded off of them. The appearance of Pseudacirs, for example, did not, and almost certainly cannot, cause the extinction of the speciose genus Hyla. Hence the cladistic practice of disqualifying paraphyletic higher taxa is, as Mayr pointed out, "impractical, destructive and scientifically untenable."

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