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Re: four winged Archaeopteryx

Graydon (oak@uniserve.com) wrote:

<All known birds can fluff their insulative feathers, and it's very hard to see
how a non-mobile insulative structure could survive selection pressure, so the
least hypothesis is that the proto-feather could move.  Not a lot, but there
would have to be some mechanism to raise and lower it to control the amount of
trapped air. [...] Since an _immobile_ aerodynamic feather doesn't make sense
from an aerodynamic standpoint, evolving from a mobile insulative feather to an
immobile aerodynamic feather is a very strong claim. [...] What the mobility
mechanism was we don't know, and probably cannot know, but the idea that there
necessarily wasn't one at all is an awfully strong claim.>

  The very premise that skin-muscles, which are used to fluff the hairs on your
arm or the feathers on a birds breast, can be used to analogize the spreading
of wing or tail feathers, which are otherwise anchored in ligaments and muscles
that have rather strict motions concerned their movement, is also about as
strong as a claim as I making the opposite. Neither have any evidence to back
them up, and thus both appear equally likely. My premise that skin-muscles
which could be used for this purpose are NOT the ideal null hypothesis for the
condition advocated is based on the argument that the skin-muscles for feather
movement are an exaptation IN birds, and do not neccessarily precede them, and
they should NOT be considered present in the tail without any evidence FOR the
case. This doesn't mean I am saying they DO NOT exist, but that there is no
evidence to presume they do except the fancy that Archie -- like birds -- has
this ability. That idea is based only on the archetype that as a bird, it
should do everything a bird can do. Romantic, to say the least.


Jaime A. Headden

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)

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