From: swf@teradata.com (Stanley Friesen)
Newsgroups: talk.origins
Subject: Re: Friesen on elastics and sauropod necks
Date: 29 Sep 92 21:11:02 GMT
Reply-To: swf@tdat.teradata.com (Stanley Friesen)
Organization: NCR Teradata Database Business Unit

In article <40@fedfil.UUCP> news@fedfil.UUCP (news) writes:
|[Me]
|| Now Ted, in case you didn;t understand this moderately technical description,
||  McGowan just said that ligaments are *elastic*, like rubber.  (That's what
||  "low Young's modulus" means.
|
|The reality is that nothing of flesh and blood could hold the torque 
|involved with the notion of holding a sauropod neck out near horizontally.

On what evidence do you base this conclusion?

|Again, scientists are now claiming that sauropods held their necks out
|horizontally because they'd not have been able to get blood to their
|heads were they to hold them as high as the bones would appear to allow for.

And *I* repeat, they have concluded that *some* (not all) sauropods held
their necks out horizontally because that is how the bleeping bones *fit*
together.  Brachiosaurus is still modeled with a *vertical* neck, because
that is how *its* bones fit together.

You are *still* getting diplodocids and brachiosaurids mixed up!

|This would generate a torque load easily in the hundreds of thousands of
|foot-lbs;  for instance, if a 360,000 ultrasaur's neck were to weigh
|30,000 lbs from the shoulders outwards, and that seems conservative, and
|if the center of gravity of that neck were ten feet out from the shoulders,
|he would have to deal with 300,000 ft-lbs of torque to hold his head
|out horizontally as scientists are now claiming.

Treated as a rigid bar, with a single lever point.
Treated as a flexible chord, with a distributed load support, the
results are quite different.

|Stanley is now claiming elastic ligaments did the job.  Try an experiment,
|Stanley:  Get yourself one of the rubber-powered toy aeroplanes flown either
|in open competition or in the Wakefield cup events, wind the rubber all the 
|way, tie the prop agianst the fusalage, and then leave it for a day and
|come back to it.  Then tell us what kind of shape the rubber strands
|are in.

Rubber bands are *not* living tissue.  Living tissue has this nice little
property called self-repair.  It is only after death that ligaments undergo
degradation.

|  Turko/Mongol bows, by the way,
|are of wood, animal horn, sinew etc.  The same stuff you're claiming
|would do such a wonderful job of holding the 300,000+ ft-lbs of torque
|of a sauropod's neck,

The bows are made form *dead*, *dried* animal parts.  A big difference.

|There is one other minor problem I might mention which a sauropod would
|encounter were he to hold his heck out horizontally, as scientists are now
|claiming they must have.  He'd starve.  The good leaves are all above the 
|20' - 30' level.

The leaf level depends on the type of vegetation.   Since the best
reconstruction of the Morrison environment are of a rather dry, seasonal
environment, with tall trees restricted to water courses, I think that
you are probably wrong here.  (The envoronment was dry enough to have
desert style dried lake beds - playas).
-- 
sarima@teradata.com			(formerly tdatirv!sarima)
  or
Stanley.Friesen@ElSegundoCA.ncr.com
Newsgroups: talk.origins