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Re: Long - Endothemy vs. Ectothermy



John, et al:

    The "towards bird-like levels" was as opposed to towards modern
reptillian levels.  Merely a suggestion of position on a scale from
'cold-blooded' to 'warm-blooded', not as an indicator of BAMM versus BCF.

    I believe that the original suggestion was that protofeathers (i.e.
_Sinosauropteryx_ -type integument) would have appeared as a method of
removing excess Nitrogen products from the animal's system, possibly by
exposing them to the air, lifted slightly away from skin.  I agree that I
certainly wouldn't want to carry toxins, etc. around with me for months.
Perhaps there were other chemical processes at work as well, much like the
protection afforded ducks from wetting their feathers.

    George O. - You've mentioned the nitro-excretion idea before, can you
elaborate?


        Allan Edels


-----Original Message-----
From: John V Jackson <jjackson@interalpha.co.uk>
To: dinosaur@usc.edu <dinosaur@usc.edu>
Date: Thursday, October 15, 1998 10:00 AM
Subject: Re: Long - Endothemy vs. Ectothermy


>--Original Message-- From: Allan Edels <Edels@email.msn.com>Date: 15
October
>1998 06:05
>
>
>>based on recent integument findings, it
>>certainly seems to me that several later forms were feathered.  This would
>>indicate the trend in some of the dinosauria towards 'warm-bloodedness' -
>>perhaps towards bird-like levels.
>
>As the only feathers yet found postdate the first bird, perhaps "from bird-
>. . ." would be just as appropriate if not more so than "towards bird- . .
>." - certainly more parsimonious.
>
>
>>I like the idea that feathers started as a unique way of ridding
>>the dinosaurian body of nitrogen by-products.
>
>Certain waste products do turn up in the hair, but that is not hair's
>primary raisin d'etre.  Also, when an animal wants to rid itself of
>something, it wants to get rid of it, not weave great swathes of it into a
>complicated structure and then carry it around for months on end.
>
>It is true that goldfish I have known used to extrude long strands of
>something and carry it around with them, but death followed shortly
>afterwards.
>
>JJ
>
>