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Re: Yet more reptile stuff (long)



Philidor11@aol.com wrote:
> 
> In a message dated 12/18/98 12:38:33 PM Eastern Standard Time, sankarah@ou.edu
> writes:
> 
> << In
>  essence, I've changed my argument on you: I recognize the utility of
>  grouping turtles, squamates, and archosaurs together, but dislike the
>  use of "reptilia" as a label for that grouping, mostly due to the fact
>  that it doesn't mean the same thing to most folks as it does to you.  >>
> 
> Perhaps you should stick with your original argument.
> If reptiles are defined as something like cold-blooded egg-layers with scales
> then you have a perfectly workable definition.  Dinosaurs and birds disappear
> from your grouping, but then so did mammals under any definition.  Do you
> really want to keep birds as reptiles?

That's not a good definition, though, as it's paraphyletic.  Works for
most people, but my goal was a grouping and means or recognizing said
grouping which was both valid and easily accessible to most folks.

> The common descent element becomes less of a hindrance if the groupings are in
> fact 'arbitrary'.  Definitions become based not on 'historical' connections,
> but on description.  Of course, your definition is equally arbitrary, but is
> splitting so bad if based on those obvious aspects you've been talking about?

Splitting isn't in and of itself, but consistency is essential IMO.  I
really do think we ought to stick with monophyletic groupings so that we
avoid problems of convergence and what-not, as well as including all
relevant animals when we're talking about a family or class or other
such group.