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Re: tweet-tweet



On Sun, Apr 13, 2008 at 10:28 PM, evelyn sobielski <koreke77@yahoo.de> wrote:
> > Arbitrary
>  > ranks like
>  > "Order", "Family", etc. are not necessary (or, IMHO,
>  > particularly
>  > useful).
>
>  If they are used to denote major shifts in ecological
>  niche/ecomorphology, they are not arbitrary

They are still arbitrary, unless you can come up with some discrete
metric of ecological change and correlate this metric to ranks.

> and actually quite useful - as they will then also denote
>  a major shift in *how* evolution acts upon a lineage.

It seems to me there are already plenty of far better ways to discuss
this without bringing Linnaean ranks into the mix.

>  The problem of paraphyly remains, namely at very high
>  and very low ranks. The former can be solved by a
>  phylogenetic nomenclature; the latter... well...
>  doi:10.1111/j.1558-5646.2007.00149.x
>  doi:10.1016/j.cub.2006.03.005
>  doi:10.1642/0004-8038(2004)121[0930:AHASGF]2.0.CO;2
>  doi:10.1642/0004-8038(2005)122[0949:POTMAP]2.0.CO;2

I think phylogenetic nomenclature can solve this sort of problem, too,
if we recognize that clades are not the only possible type of
phylogeny-based taxon. They are one of the most salient and useful
types, and there are certainly the best-established type, but who
knows what the future may bring for phylogenetic nomenclature?

(Incidentally, it's not immediately obvious to me that clades aren't
enough here--as long as clades are considered sets of organisms, not
sets of taxa. I'll continue to look at these refs, though--thanks for
providing them.)
-- 
T. Michael Keesey
Director of Technology
Exopolis, Inc.
2894 Rowena Avenue Ste. B
Los Angeles, California 90039
http://exopolis.com/
--
http://3lbmonkeybrain.blogspot.com/