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