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----- Original Message -----
From: "GUY LEAHY" <email@example.com>
To: <firstname.lastname@example.org>; "Michael Habib" <email@example.com>
Sent: Monday, June 02, 2008 9:01 PM
Subject: RE: Chaoyangopteridae
What about long necked birds such as swans and flamingos? Swans in
particular are interesting in this regard, since they not only exhibit
large >tracheal dead space but are known to fly at considerable altitudes.
Swans have relatively larger torsos and lungs, and relatively shorter necks.
I regard endothermy and its resulting elevation of aerobic power as an
essential precondition to the development of powered flight.
It's not required as a precondition for soaring flight -- only contiuous
flapping flight. There's no evidence that pterosaurs developed flapping
prior to soaring. Nor any evidence to the contrary either. And, there is
no requirement for substantial aerobic power in flap-gliding mode. A
soaring animal has the option of flapping in short, anaerobic bursts,
repeated only when atmosperic lift is temporarily unavailable and after
sufficient recovery time.
I don't believe it's any coincidence that all living vertebrates which fly
have both. .......Ectothermic flyers would be highly at risk for fatigue
Not if their primary mode of flight was dynamic soaring.
and metabolic recovery between flights would take much longer than an
endotherm of comparable size.
Not necessarily. Odds are that an ectothermic soaring animal would land
after a period of soaring, and would be able to anaerobically launch again
immediately, if need be. That said, note that I believe the earliest known
pterosaurs were endothermic.
Plus, fatigue during flight might have certain survivability
If they aren't flapping during flight, why would they fatigue?