Re: Sort Your Story Out! (Was: 2 refs that were once new...)

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

David Marjanovic wrote:

> > I don't think this proves anything.  The fact that modern gliding
> > birds have asymmetry within the range of modern flying birds is purely
> > circumstantial -- plus it's the sort of convergence you'd expect,
> > since an aerodynamically efficient feather is aerodynamically
> > efficient whether used for flapping or gliding.
>
> So Archie didn't use its feathers for anything aerodynamic, no?

If _Archaeopteryx_ used its wing feathers for passive gliding, then the 
feathers still served an *aerodynamic* purpose.  The issue here is what sort 
of aerodynamic purpose these feathers were used for.  I find it difficult to 
believe that long, planar, asymmetric, closed-vaned feathers were originally 
developed for a non-aerodynamic purpose (brooding, display, whatever) and 
only later were put to use in aerodynamic locomotion.

One proposal is that the wings of _Archaeopteryx_ were only useful for very 
short flights.  The wing was used for lift and propulsion by flapping (i.e. 
powered flight), but the pectoral musculature was insufficient for sustained 
flapping.



Tim

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