Re: Steadman's review of Mesozoic Birds

["Tim Williams" <twilliams_alpha@hotmail.com>]

David Marjanovic wrote:

> > >The debate over whether the magnetite contained
> > >in the Martian meteorite is indeed biogenic
> > >(and therefore indicative of past or present life on the Red Planet)
>
> "Therefore"? We'd still have to rule out contamination -- colonization of
> the meteorite by bacteria while it was lying around on the Antarctic ice.
> IMHO that's quite likely what happened.

This is off-topic, so I'll be brief.  (Then again, I started it.)  
Terrigenic contamination is unlikely, since the crystals are buried in a 
carbonaceous matrix that is itself of Martin composition.  The debate has 
long since shifted to whether the crystals are of abiotic or biogenic 
origin.

> It is the way Feduccia keeps up his
> hypothesis. For example, it is plain obvious from all of his writings that
> he has no good working knowledge about dinosaurs.

This is painfully true.  Some of his statements about dinosaur anatomy or 
paleoecology date from the 1960's.  Like David, a lot of the assertions made 
by Feduccia and Czerkas and Olson make me cringe.  Many of the assertions 
have been contradicted over and over again, and in a multitude of papers 
(many of which have appeared in such obscure journals as Nature and Science 
and American Novitates).

Further, there are the internal inconsistences of his 'hypothesis'.  For a 
long, long time Feduccia was convinced that the osteological similarities 
shared by dromaeosaurids and primitive birds were due to convergent 
evolution.  Then dromaeosaurids turned up with honest-to-God feathers.  
Woops.  Suddenly Feduccia was sidling up Czerkas' hypothesis: dromaeosaurids 
and birds were closely related after all, but neither evolve from dinosaurs.



Tim

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