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Re: Bradytely (thanks Jaime) + Trees of Life



>      And I also complete agree with you that dromaeosaurs were not
> bradytelic at all, and in my Interstate example, I said that evolutionary
> rates or speeds on the dromaeosaur "offramp" probably did not slow down.
If
> the  K-T extinction had killed off all of the birds (Aves) and some
> dromaeosaurs had survived and diversified instead during the Cenozoic, I'd
> be classifying birds as an extinct family (maybe two),

That's why I don't like ranks -- they are closer to the way human brains
work, but what actual information to they carry?

Question -- what is bradytely? A "broad range of goals"?

> and probably be
> defending a Class Dromaeosaurea (and trying to decide whether it is less
> arbitrary to put the bird family in Reptilea or Dromaeosaurea).

That's why I don't like paraphyletic taxa (above the species level, of
course). These examples are all sauropsids, ..., diapsids, ..., dinosaurs,
..., theropods...
        (Nitpicking: I would have liked it if a term had been coined for
holophyletic Dinosauria and if Dinosauria were discarded instead. Dinosaurs
aren't lizards, and "fearfully great" is a generalization. But such a term
isn't there, and even if someone had a good idea for such a name, it's too
late. But Sauropsida, which was coined as holophyletic by Seeley, is there
and can and IMHO should be used instead of paraphyletic Reptilia.)

>      The common ancestor of life on Earth (I use the term "Geobiota",
rather
> than "Biota")

Hm. Good idea at first glance, but if there is or was life on Mars, it is
very likely to have a common origin with that on Earth, because prokaryotes
can very probably travel between planets in rocks blown off of a planet by
an impact, and life may even have originated on Mars and later traveled to
Earth. "Geobiota" could be a misnomer.

How official is "Biota", anyway? I have never seen it in print...

>       The only thing I would disagree with (below) is that I believe that
is
> not nearly as difficult as you might think to determine what is
> plesiomorphic for "Archaea".  Unlike Woese, I believe that they are a
> comparatively derived and later-evolving branch of thermophilic bacteria
> (and should be called Metabacteria, as Osawa and Hori named them way back
in
> 1979, rather than the totally inappropriate name "Archaea" proposed in
> 1990).

Interesting, why do you think so? (And where would you look for the origin
of Eucarya, which is commonly viewed as the sister group of Archaea?)

>       Since 1995, I have been warning that Woesian "Trees of Life" are
> almost certainly totally misrooted and badly skewed as a result.  When
such
> trees (actually just "Tree of Ribosomes") are finally discarded and real
> "Trees of Life" replace them, this will be a terrible black eye for
> cladistics, and for a while I suspect it will overshadow and throw a pall
> over the relative successes of cladistics in the study of dinosaurs.

Pardon me :-], I am sure you won't think it's appropriate if I compare this
to Feduccia's statement "The theropod origin of birds, in my opinion, will
be the greatest embarrassment of paleontology of the 20th century", but what
are your arguments? :-]

> *********************************************************
> >From: "Jaime A. Headden" <qilongia@yahoo.com>
> >Reply-To: qilongia@yahoo.com
> >To: dinosaur@usc.edu
> >Subject: Bradytely and Evolutionary Distance: Plesiomorphy
> >Date: Thu, 11 Jan 2001 00:02:26 -0800 (PST)
> >
> > distance logarhythms,

related to arithmetics, not rhythm... :-)

> >   A last example, close to home: Ceratopsidae have numerous
> >autapomorphies that perhaps rival any other dinosaur group. So
> >do Ankylosauria. Slowly, we find basal forms along these
> >highways that reduce the distance each organism differs from a
> >set group as one takes into account the truly gradistic
> >relationship of _all_ taxa.

=8-) That's why I don't like "evolutionary distance" to be used in
classifications. A few new fossils, and taxonomy goes the way of the
pterosaur. :-( .