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Re: OCCAM'S RAZOR & THERIZINOSAURS



--Original Message--  From: Jonathon Woolf Date: 03 August 1998 11:05
Subject: Re: OCCAM'S RAZOR & THERIZINOSAURS


>John V Jackson wrote:
>
>> --Original Message--  From: Jonathon Woolf   Date: 02 August 1998 19:58
>> Subject: Re: OCCAM'S RAZOR & THERIZINOSAURS
>>
>> >Um, could you answer a question for me, please?  If the presence of
>> feathers
>> >necessitates a flying ancestry, then where did feathers first come from,
>> and
>> >why?
>> >
>> >-- Jon W.
>>
>> i):  Hair/fur originating as developments from reptilian scales much
along
>> the same lines as in pterosaurs and mammals, serving the joint purposes
of
>> insulation, and drag for minimising fall damage and helping steerage
during
>> leaps.
>>
>> ii):  Simple hair structures becoming progressively more complex and thus
>> increasing drag/weight ratio, eventually to the point where the
>> proto-feathers align horizontally when the creature is in flying squirrel
>> pose.  With tail and arm feathers in this configuration, optimised to
oppose
>> downward movement, the capability to glide in simple table-mat style
would
>> smoothly and inevitably develop.  It is at this stage that aerodynamic
>> features of individual feathers would become subject to evolutionary
tuning.
>>
>> Note the tendency of feathers in flightless birds to move away from fully
>> interlocking streamlined and sub-spatulate form, towards either
"explosive"
>> or longer and more hairlike forms, depending on usage.
>>
>> Um, I hope that helps.
>>
>
>It does.  Now the next question: if feathers evolved in either of the ways
you
>describe, _before_ developing into an organ of flight,  [snip]


I don't see how you could get that meaning from what I wrote!  Paragraphs i
& ii are successive stages.


JJ