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Re: Arms into wings



I wrote:

<<Because extant birds use one behavior apparently primary to another
does not presume that an ansestral bird did so.>>

and DG wrote:
 
<That's not my point. My point is that since almost all birds use
their wings for flight, why not explore the idea that wings did,
indeed, evolve >for flight< (my Heavens what a radical notion!!)>

  I for one, percieve this as circular reasoning. That wings being
used (in extance) by birds to fly with precludes the development of
"wings" for the purpose of flight is semi-curcular reasoning. It
suggests that perhaps these animals had a goal to reach towards. "I
think someday, my descendants will keep swinging their arms around so
they can go up, up, up and awaaaaay into the the wild blue and catch
bugs or escape fromn your bigger relatives or such---it should only
take a hundred or so generations."

  I do not mean this as an affront or attack, so please do not take
this in that way. I'm also not trying to say that you're saying this,
or insinuating or otherwise.

  However, the arms for wings would only have developed from shorter,
less "flight"-apparent limbs. Feathers, that's anyones guess, but they
possibly weren't around until the Mid-J, in their most basal form,
while "birds" like Archie were hopping from ______ to ______ with arms
that could, in nessecity, glide and propel it through the air. A
glinding stage preceeding true flight involves feathers. If so, then
feathers reach from (around) *Eoraptor* up to Archie in full flight
capability. We certainly don't assume skin-gliding as in mammals and
those kooky lizards and snakes would have been a part -- this requires
long arms, which according to all forms of phylogenetic reasoning,
would not have existed until that ancestral maniraptoran. Hence, long
arms, _then_ feathers (*Caudipteryx*, in more ways than on, suggests a
atavistic state and I do this it was secondarily whatever, but the
asymmetrical nature of the retrices [and pelvis, and arms, and tail]
do not suggest flight was in its ancestry). This also suggests, given
avian non-feathered skin, that such flight supporting structures as
feathers would not have developed unless there was a purpose to use
them. Given phylogeny as supported by any other host of methods and
data, arms were long before the true flying animals arrived, and most
flight-supporting structures were around before arms.

  I see that climbing may have come first, then arms elongated with
feathers a short time later, then flight was enabled. Where brooding
comes in is probably around the base of Maniraptora, given *Oviraptor*.

  Shoot where ye will.  

<before looking at other, less likely reasons for the appearance of
wings (e.g., display, brooding, predatory striking tools, insect
traps) and the strange exaptational scenarios that these entail.>

  Except for the latter two options, I fail to see the fallacy of
likelyhood these have in them. The "predatory striking tools" may be
rewritten as "climbing/grapplin tools" and I think the last has
already been drummed out of the corps.

<It may, in the final analysis, turn out that it is quite impossible
for wings to have evolved for flight; that, unlikely as it may seem,
wings >must< have evolved for some other purpose and were later
exapted for flight. But we are absolutely nowhere near eliminating the
argument that the main reason wings evolved is simply to increase
birds' control over their aerial trajectories--to fly.>

  Or that _each_ feature was developed and used for entirely different
purposes that were all at one final point developed into flight when
it appeared that control over an aerial trajectory was possibly. It
had to get into a possition to be in their before it could actually
_be_ there, and all the other features leading to it would have been
successive or unassociated adaptations that enabled this all in
something quite like Archie or *Deinonychus*.

==
- Greek proverb: "Knowledge is Inherent;
  Stupidity is Learned." -

Jaime A. Headden

Qilong, the website, at:
( http://members.tripod.com/~Qilong/ )
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