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Re: Campbell's even crazier than a MANIAC? (archeopteryx climbing)
----- Original Message -----
From: "don ohmes" <firstname.lastname@example.org>
Sent: Saturday, September 27, 2008 1:55 PM
They don't call them "basic principles" for nothing.
Nobody calls anything a basic principle. "Basic principle" is not a
technical term and does not have a definition. There is no official list of
Perhaps "competitive exclusion" has some modern meaning I am unfamiliar
with, so I will substitute the term 'competitive superiority' in it's
stead. It is an essential component of the natural selection concept, and
a reality familiar to everyone. Mechanics are only relevant to evolution
from the perspective of natural selection, so it is considerably more
accurate to say "Mechanics are notoriously difficult to demonstrate, in
fact, and it is still uncertain how important they are in determining
specific evolutionary patterns."
Er... no. For natural selection you don't need any competitors at all, just
a population and an environment which may or may not contain competitors.
And "only" contradicts "relevant to evolution from the perspective of
The mechanical hurdles to which I refer are not mere
postulates, incidentally - the specific structure and
planform of many living gliders is such that rapid
oscillations of the airfoils would have a negative impact
True, but sometimes theory is misleading. Solar thermal power is more
"efficient" than photovoltaic panels (PV), for example. So when Google
funded (partially) a 720 acre solar power plant in the Mojave they
naturally went w/ solar thermal. However, the concentrators must be washed
w/ water twice a week to maintain that "efficiency"!!!
"Theory has been wrong before, so it can be safely ignored"? Surely that's
not what you are trying to say?
No flying squirrel will ever increase glide length by waving it's paws in
mid-flight, but it is possible for selection to enhance control motions
that occur at the end of the glide.
What exactly would those control motions look like, and how could they
evolve into flapping?
I use the behavior of the common anole as a base model, even though they
are not bipeds.
And even though they are much better climbers than just about any
Is this a good time to point out that earliest known birds, bats and
ptero's all had long tails and wing claws
Well, no. That's because possessing these features is _normal_. They are
_plesiomorphies_ -- retained character states.
For over a century, people looked at *Archaeopteryx*, saw the finger claws,
and thought "wow, how utterly weird, a bird with finger claws! Surely these
claws must have been a very special adaptation!" This is completely
backwards. Having finger claws is normal for birds (and amniotes in
general). Archie is normal, *Confuciusornis* is almost normal, and the
Ornithothoraces are the weird ones, despite counting some 12,000 species.
The presence of maniraptoran-style finger claws in Archie _does not need an
explanation_; what needs an explanation is the _reduction_ of these claws
that happened later.
Same for the loss of finger claws in *Nyctosaurus* and bats other than
*Onychonycteris*, and for the loss of the long tail in anurognathids,
pterodactyloids, most bats (though a few long-tailed bats still live), and
I did not say that there was no competition. I continue to assume that the
competitive barriers faced by proto-birds as they achieved lift-off were
less than they would face in an environment filled w/ real birds. And
OK, that's at least testable.
> Heh. Oh, do you have an example of "terrestrial
origins for flight"? :D
As mentioned before, birds may very well be an example.
Or not. There is debate about that... :D
Forget about it. There are not enough clades of flying animals to do
statistics with that.
Now, the clades of gliding or parachuting animals on the other hand...