[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Feathers vs patagia



-----Original Message-----
From: Ken Kinman <kinman@hotmail.com>
To: David.Marjanovic@gmx.at <David.Marjanovic@gmx.at>
Cc: dinosaur@usc.edu <dinosaur@usc.edu>
Date: Saturday, January 06, 2001 12:14 PM
Subject: Re: Feathers vs patagia


>
>David,
>     Well, I do look forward to seeing your paper.  I love new ideas.
>However, I'm not sure your objections to Larry's ideas are necessarily
>valid.  He isn't saying that birds evolved from any of the advanced
>pterosaurs you are describing, but forms which were far more primitive
which
>haven't been found (or perhaps sitting unrecognized in some museum drawer).
>     I can contemplate such an ancestral form (perhaps a little more
>pterosaur-like than birdlike) gliding from gymnosperm to gymnosperm (be
they
>cycads, conifers, or some other gymnosperm).  One line goes the pterosaur
>route, another goes the bird route, and the intermediates go extinct.  And
>if I understand Larry's ideas correctly, theropods are secondarily
>flightless birds (in agreement with BCF theories).

>     I don't know if pterosaurs and birds had a primitive gliding common
>ancestor, but I think it is a good idea to investigate such possibilities
>(just as you are apparently doing in developing some other possible
>scenarios).  Whether Larry is wrong or right, I don't think his reasoning
is
>teleological, at least in the ways you seemed to be pointing out.  If they
>do have a common gliding ancestor, I suspect it would be more
pterosaur-like
>than birdlike.  Anyway, looking forward to your paper.
>                    -----Ken


Thanks for the defensive stance Ken! I should perhaps always post my
website, since it is the only source of information for my "different point
of view". (Perhaps I`ll write a paper myself, ......some day!). So, once
again,...here it is for anyone and everyone`s perusal:
http://www.capital.net/~larryf/

Yes, I`m speaking of a very early common ancestor, which had smaller wings
to begin with, and a smaller cranium (therefor not too "top-heavy"), and
still possessing clavicles. I don`t believe I`m being teleological. I`m
trying to reason what enviornmental forces may have been involved in such a
transition from a glider with a membrane to a feathered form. I believe it
was Bock who first made the claim that the natural progression would be
glider to flyer, and that a flight membrane was a necessary intermediate.

I`m not sure exactly how feathers developed,but actinofibrils arranged in a
pattern similar to flight feather rachis is very suggestive. Whatever the
path, a changeover from a fully functional membrane to feathers would have
to be gradual, and would require a "reason" for it to happen. I believe the
reason might have been the invasion of a new, and colder enviornment.
Perhaps a more upland enviornment, and natural selection acting on this
primitive wing to cut down on exposed area in a colder enviornment. Contour
feathers, once developed, could have extended to long flight feathers as the
membrane, and wing finger gradually (over generations) shrunk, until this
wing finger was itself no longer necessary.