RE: Philidor: No Class

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Richard Forrest wrote:

> The whole reptile/bird/dinosaur thing is a mess because the issue is
> complex, confused and lacking in information. 

I almost fell off my chair with laughter after reading this howler.  How
much information do you need?  I would aver that it is not the *lack* of
information that is the problem, but one's ability to understand and digest
it.

I'll reiterate something Dr Holtz mentioned.  No other issue - except
possibly hominid evolution - seems to possess such a penumbra of emotion as
the issue of the origin of birds.  The evidence favoring the origin or birds
from theropod dinosaurs is no more "controversial" than equally
well-supported phylogentic relationships: e.g. the evolution of titanotheres
from perissodactyls, snakes from lizards, plesiosaurs from sauropterygians,
mammals from therapsids, plants and animals from single-celled bacteria...

> The basic rule of any computer programme is 'garbage in, garbage out'. 

Ah, a Luddite.

> My observation is that papers publishing cladograms take raw data on 
> characters without any theoretical model of the combination of genetic, 
> ontogentic and biomechanical forces moulding those characters. 

Not so.  Authors make a conscious effort to consolidate or combine
characters that are developmentally or functionally linked.  The mammalian
dentition is one good example.  

And while we're on the topic, please show me an example of a published
cladogram that is in defiance of "genetic, ontogentic and biomechanical
forces".



Tim


------------------------------------------------------------ 



Timothy J. Williams, Ph.D. 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 9359