New(ish) paper II

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

> Charles A. Long, G. P. Zhang, Thomas F. George & Claudine F. Long. (2003) 
> Physical theory, origin of flight, and a synthesis proposed for birds.  
> Journal of Theoretical Biology 224: 9-26.


Contains some interesting aerodynamic discussion, though the equations made 
my head spin at this hour of the day.  Unfortunately, the paper has a poor 
phylogenetic grounding; among other things, _Protoavis_ and _Longisquama_ 
are considered serious contenders as avian ancestors, and _Microraptor_ is 
called a troodontid.  The authors also revert back to the old "ground-up" 
versus "trees-down" dichotomy.  Long et al. (2003) also make some very silly 
statements about competing hypotheses, and they miss the point entirely 
concerning the WAIR hypothesis.  Here are some of the wilder and stranger 
statements contained in the paper:

> From the 'Statement of the Bleeding Obvious' File:

"Peter Mackovicky discounts the furcula as a distinctively avian feature 
(personal comm.)."  Hmmm... aren't there one or two (or maybe thirty or 
forty) papers that have already established this?


> From the 'Here We Go Again' File:

"_Longisquama_ possessed feather-like epidermal extensions of several kinds. 
These included some on the postaxial forelimbs that closely resemble flight 
feathers. The feathers seem homologous with bird feathers, which is perhaps 
not true (Alan Feduccia, pers. comm.; also see [Zhang and Zhou (2000]) of 
so-called feathers of the small dinosaurs (their filaments may not be 
derived from scales as are true feathers). The feather-like structures of 
_Longisquama_ suggest that birds may not be descended from the hypothesized 
small theropod dinosaurs after all, but from an archosaurian glider that 
perhaps gave rise later to some feathered forms with bipedal locomotion."


> From the 'Something to Do on a Rainy Afternoon' File:

"Chickens have been observed ... thrown from the roof of a 12-story Kansas 
building to onlookers at a parade; the chickens flew less than 50 m 
horizontally but fluttered enough while falling to avoid injury."  Pleased 
to hear it.


Finally, there's this assertion about WAIR, from the 'Splat!' File

"Were it not for what we have described as flutter-gliding, to soften 
impacts on landing, an accelerating vertical climb and subsequent fall would 
confer limited survival and evolutionary fitness."  In other words, in the 
author's view WAIR says that pro-avians ran up vertical surfaces until they 
ran out of steam, then fell back down to the ground again with a (painful) 
thud.  It's amazing that partridges haven't gone extinct.  Perhaps young 
partridges habitually wear crash helmets.



Tim

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