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Re: Ad Explanorum Origam
<<Origin of birds is separate, possibly, from origin
<Origin of birds is indeed separate from origin of
flight! But--what about origin of flight >in birds<?>
Here's how I see it:
The origin of flight (general) involves adaptation
of a foil for control of some pressure while plying a
gaseous medium (preferably air). Assumptive (again,
not you) is the stationary -> gliding -> volant
evolutionary series. No gliding animal in existence is
apparently developing the ability to fly by poweref
strokes. A gliding stage is seen as a possible, but
not neccessary, intermediary from the static,
terrestrial/arboreal form to the extremely mobile,
volant form. All known gliders cannot control lift
except to decrease, because they lack the power
stroke. Of course, penguins use the power stroke to
propel themselves through a liguid medium, but they
were still volant, and now amphibious. I consider this
a different principle, and one discussed last year
vigorously. George, I think you didn't recieve much
dissent on saying penguins still flew, though it was
The origin of birds is a matter of phylogeny, and
precise sister-group relationships have not been
approached, though suggested.
The origin of flight in birds is a third
consideration, which was my point, and resolution
requires understanding of the phylogeny of birds, and
general knowledge of the origin of flight will give us
knowledge of how to identify true volant adaptations;
homologies are oinly homologies without witnessing the
evolutionary sequence that would analogize the
predatory strike of some theropods to the power stroke
of birds. Steve Gatesy recently reported working on
the forelimbs of dinosaurs and birds, and so this may
be resolved soon.
This gives us a rather hopeful outlook to resolving
the question of flight in dinosaurs, and that's one
step closer to flight in birds, and their requisite
origins and hypotheses thereof.
To reiterate, the origin of flight (volantis origo)
and the origin of birds (avis origo et avus) are
separate questions; the question of the origin of
flight in birds (volantis origo avis) requires
resolving (or at least reasonably) the first two
subjects. I suggest trying to answer those, before we
tackle the third. This way, we'll be on less shaky
ground, and we would all be vindicated. I personally
have hopes that this will prove you right, George, but
I would like the list in general to consider that even
so simple a question as how an animal chewed its food
requires asking a multitude of hypotheses and there is
some testing for each one.
"Chaos" Theory states: "that which is simple, is
truly complex." Someone get that in Latin for me?
Jaime "James" A. Headden
"Come the path that leads us to our fortune."
Qilong---is temporarily out of service.
Check back soon.
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