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Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)



----- Original Message ----- From: "Erik Boehm" <erikboehm07@yahoo.com>
Sent: Saturday, September 27, 2008 1:32 AM


I don't see how this follows.

If it can fly... it can glide - aside from direct thrust flight (rockets, VToL jets).

Agreed.

I don't think the ability to fly powered could have possibly come before the *ability* to glide (that isn't to say they would routinely stop flapping midflight)

I still don't see how this follows. Especially when I consider the lack of tertials in Archie.


> I think its highly likely powered flight did not come
before soaring.

The fossil record points in the opposite direction: the
bats still haven't got the idea of soaring, and the birds
seem to only have evolved it after the Mesozoic was
over. Even the pterosaurs started with small forms that
didn't have particularly long wings.

Well, we don't know if bats ever did soar at any point in the past, and I am specifically implying ridge soaring, not using thermals.

"Know" is too strong a word, but there's no evidence any bat ever soared, neither direct nor phylogenetic nor even geographic. Ockham's Razor thus argues against it.


And how actually would soaring evolve into flapping?

[...] I still think ridge soaring was probably one of the first niches a ptero or dinobird occupied once it had wings giving it any kind of gliding ability, before the wings and muscles were large enough for powered flight.

The wings, at least, may well have become large enough for flight long before flight started. That's because the wing feathers of birds may well have evolved for brooding and/or display rather than any aerodynamic function.