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Re: a rose by any other name(was fish & dogs)



In a message dated 12/2/00 10:04:37 AM EST, kinman@hotmail.com writes:

<< Sometime when kids ask such appropriate questions (as those you 
 quoted), you might try the following.  Ask them if it wouldn't make sense to 
 classify only regular dinosaurs (non-avian) in Dinosauria, the birds in 
 Aves, and just put a special marker, like {{Aves}}, within the Dinosauria 
 classification next to the dinosaurs which the birds evolved from. >>

Once you have defined a clade A and a subclade B, you have also completely 
and unambiguously defined the paraphyletic group A-B, so there's no a priori 
reason not to employ such a group as a taxon (there may be >other< reasons 
not to do so, but they're irrelevant here). In cladistic taxonomies, only 
clades may be used as taxa, but doing so is a subjective decision that 
ignores the benefits of using paraphyletic groups in taxonomies.

"Fish," for example, may be unambiguously defined as all vertebrates that are 
not tetrapods. It is not at all the "mishmash" group that cladists would have 
one believe it is. Defined this way, lampreys, sharks, rays, and teleosts are 
all "fish." Why would anyone have a problem with this?