From: gecko@zooid.guild.org (GECKO)
Newsgroups: talk.origins
Subject: Ted's Flying Circus (Long & Drivelly)
Date: 23 Jul 92 01:01:00 GMT

 
 
  Ted Holden (news@fedfil.UUCP) writes: 
 
>The felt effect of the force of gravity on 
>earth was much less in remote times, and only this allowed such giant 
>creatures to fly.  No flying creature has since RE-EVOLVED into anything 
>like former sizes, and the one or two birds which have retained such 
>sizes have forfeited any thought of flight, their wings becoming 
>vestigial. 
 
     IF this were so, one would expect to find flight adaptations 
     (hollow bones, deeply keeled breastbone, compact torso, fused 
     back vertebrae, forward/outward orientation of shoulder joints) 
     amongst small active fliers of ancient times - Pterodactylus, 
     for example - to be less developed than those of small active 
     fliers of modern times.  Yet this is not what one finds at all; 
     these adaptations are as highly developed in the extinct pterosaurs 
     as they are in contemporary birds and bats of the same size range. 
 
     As for 50-pound-plus fliers, such extreme changes for the sake of 
     lightness as those Adrian Desmond describes of Pteranodon and 
     Quetzalcoatlus would presumably be unnecessary under the effects 
     of attenuated gravity.  It is absurd to suggest that such creatures 
     must conform to your mathematics when it is still not fully 
     understood how some modern fliers get off the ground! 
 
 
 
>A book which I've mentioned a couple of times here is Adrian 
>Desmond's "The Hot Blooded Dinosaurs". 
> 
> (Text on Pteranodon by Desmond deleted) 
> 
>There is one other problem.  Desmond notes a fairly reasonably 
>modus operandi for the pteranodon, i.e. that it had a throat pouch 
>like a pelican, has been found with fish fossils indicating a 
>pelican-like existence, soaring over the waves and snapping up fish 
>without landing.  That should indicate that, peculiarly amongst all 
>of the creatures of the earth, the pteranodon should have been 
>practically IMMUNE from the great extinctions of past ages. 
>Velikovsky noted that large animals had the greatest difficulty 
>getting to high ground and other safe havens at the times of floods 
>and the global catastrophes of past ages and were therefore 
>peculiarly susceptible to extinction.  Ovid notes (Metamorphoses) 
>that men and animals hid on mountain tops during the FLOOD, but 
>that most died from lack of food during the hard year of the FLOOD. 
>But high places safe from flooding were always there;  oceans were 
>always there and fish were always there.  The pteranodon's way of 
>life should have been impervious to all mishap;  the notion that 
>pteranodon died out when the felt effect of gravity on earth 
>changed after the flood is the only good explanation. 
 
     Well now, this is not really a problem at all unless one 
     happens to be a creationist ;-).  The BIG FLOOD is what is 
     called a MYTH, and there is nothing in the fossil record to 
     suggest thst a global flood ever occured or could occur. 
     Mass extinction, it may be confidently stated, has absolutely 
     nothing whatsover to do with floods.  Certainly doesn't explain 
     the extinctions of fish, does it? 
 
 
>Back to Adrian Desmond for more on size as related to pterosaurs 
>now: 
> 
> 
>     It would be a grave understatement to say that, as a flying 
>     creature, Pteranodon was large.  Indeed, there were sound 
>     reasons for believing that it was the largest animal that ever 
>     could become airborne.  With each increase in size, and 
>     therefore also weight, a flying animal needs a concomitant 
>     increase in power (to beat the wings in a flapper and to hold 
>     and manoeuvre them in a glider), but power is supplied by 
>     muscles which themselves add still more weight to the 
>     structure. -- The larger a flyer becomes the 
>     disproportionately weightier it grows by the addition of its 
>     own power supply.  There comes a point when the weight is just 
>     too great to permit the machine to remain airborne. 
>     Calculations bearing on size and power suggested that the 
>     maximum weight that a flying vertebrate can attain is about 50 
>     lbs: Pteranodon and its slightly larger but lesser known 
>     Jordanian ally Titanopteryx were therefore thought to be the 
>     largest flying animals. 
> 
> 
>Notice that the calculations mentioned say about 50 lbs is max for 
>either a flier or a glider, and that experience from our present 
>world absolutely coincides with this and, in fact, don't go quite 
>that high;  the biggest flying creatures which we actually see are 
>albatrosses, geese etc. at around 30 - 35 lbs. 
 
     All this actually means is that at the present mathematical 
     understanding of flying animals, nothing over 50 pounds can 
     stay aloft.  And yet clearly they did; how exactly they did 
     this remains unclear.  It is irrational to somehow interpret 
     this as obvious proof that the felt effect of gravity on Earth 
     was once much less than it is now, particularly as there are 
     a great many reasons to believe that such a thing not only didn't 
     happen, but is technically impossible. 
 
 
> (Stuff on Quetzalcoatlus by Desmond deleted) 
> 
>Note that Desmond mentions a number of ancillary problems, any of 
>which would throw doubt on the pterosaur's ability to exist as 
>mentioned, and neglects the biggest question of all:  the 
>calculations which say 50 lbs are max have not been shown to be in 
>error;  we have simply discovered larger creatures.  Much larger. 
>This is what is called a dilemma. 
 
  Adrian Desmond also writes this: 
 
    "It is not usually appreciated just how light this glider with 
    twenty-three-foot wings really was, and without that realization 
    all sorts of fantastic notions have been devised to allow PTERANODON 
    to remain aloft.  It has been supposed, for example, that the modern 
    atmosphere was much too thin for these creatures, and that 
    consequently in Cretaceous times the atmosphere must have been twice 
    as dense, allowing PTERANODON literally to float on air.  PTERANODON 
    really had no need of such atmospheric assistance." 
 
 
  Desmond clearly does not believe that vastly different conditions 
  were necessary on Cretaceous Earth (notice the usage of CRETACEOUS 
  rather than ANTEDILUVIAN) for Pteranodon to soar.  As for fantastic 
  notions I must confess that the Saturn Theory is, even considering 
  the laughable Atmospheric Density Theory, without a shadow of a doubt 
  the silliest and most contemptible crackpot idea I have ever heard, 
  with the possible exception of the Hollow Earth Theory.  This is, of 
  course, excluding the possibility that this is merely an elaborate 
  ruse meant to perplex us all and convince us that you are as mad as 
  a March hare or perhaps an opium fiend, in which case it is truly 
  brilliant :^). 
 
 
 
 
>Then I come to what Robert T. Bakker has to say about the Texas 
>Pterosaurs ("The Dinosaur heresies", Zebra Books, pp 290-291: 
> 
>   "Immediately after their paper came out in Science, Wann Langston 
>   and his students were attacked by aeronautical engineers who simply 
>   could not believe that the big Bend dragon had a wingspan of forty 
>   feet or more.  Such dimensions broke all the rules of flight 
>   engineering;  a creature that large would have broken its arm bones 
>   if it tried to fly...  Under this hail of disbelief, Langston and 
>   his crew backed off somewhat.  Since the complete wing bones hadn't 
>   been discovered, it was possible to reconstruct the Big Bend 
>   Pterodactyl [pterosaur] with wings much shorter than fifty feet." 
> 
>The original reconstruction had put wingspan for the pterosaur at over 
>60'.  Bakker goes on to say that he believes the pterosaurs really wre 
>that big and that they simply flew despite our not comprehending how, 
>i.e. that the problem is ours.  He does not give a solution as to what 
>we're looking at the wrong way. 
 
  More specifically, Bakker goes on to say this: 
 
    "I believe Langston and his Texans were right - the Big Bend aerial 
    leviathan was stupefyingly large.  Mechanical engineers go often 
    astray when analysing the strength of skeletons.  The most common 
    difficulty with their method is that they calculate the strength of 
    an arm bone as though the bone by itself had to withstand all the 
    stresses of flapping the wings.  If the pterodactyl were a man-made 
    machine, the wing skeleton would indeed bear all the stress.  But 
    naturally evolved arms are far superior to mechanical ones.  The 
    bundles of muscles sheathing the arm bones of birds or humans 
    contract to reorient stresses when the body is excercising 
    vigorously.  Such contractions are automatic, since the muscles are 
    sent a constant flow of orders from the posture-control centers of 
    the nervous system.  Therefore a live QUETZALCOATLUS was stronger 
    than an engineering analysis of its bones might indicate.  Moreover, 
    calculating the stresses in a sixty-foot pterodactyl's wing is also 
    subject to extreme variation - the Big Bend animal may well have 
    flapped its wing from the wrist and not from the shoulder, for 
    example.  And in fact until the joints of the wing are clearly 
    understood, any attempt to calculate stresses remains dubious at 
    best.  In general, I believe it dangerous to argue a priori that 
    QUETZALCOATLUS couldn't have been as big as seems indicated.  The 
    theories of bioengineering relating to flight in live mammals are 
    still too crude to yield anything more than imprecise boundary 
    conditions that set limits only on the most extreme possibilities." 
 
 
  So essentially, Bakker thinks that the beastie was able to fly even 
  under normal Earth conditions, and that the engineers simply haven't 
  figured out exactly how they managed this yet (and I tend to agree; 
  after all, at one time it was mathematically immpossible for bumble 
  -bees to attain active flight, yet it didn't seem to worry them too 
  much ;-> ).  Bakker does NOT really mention anything about attenuated 
  gravity though, does he?  But then, it would appear that he is a 
  rational fellow of sound mind... 
 
 
> (Reams of fascinating text on the illustrious history and infamous 
>  ferocity of berkut eagles, one named Atlanta in particular, deleted.) 
> 
>Moreover, the breeding of berkuts has continued apace from that day to 
>this, including a 200 year stretch during which those people ruled 
>almost all of the world which you'd care to own at the time, and they 
>never got them any bigger than 25 lbs or so. 
 
   All this drivel about berkuts shows is that abnormally large 
   specimens of ONE modern species of eagle have difficulty 
   getting airborne.  Frankly, so what? 
 
 
>One variety of pteratorn, however, judging from pictures which have 
>appeared in Science Magazine, was very nearly a scaled-up golden eagle 
>weighing 170 lbs or so, with a wingspan of 27' as compared to Atlanta's 
>10.  In our world, that can't happen.  Just another one of those things 
>for which establishment science has no answer. 
 
   And you evidently have no reasonable explanation for it either. 
 
 
   By the way...  how do you explain the trees?  Living Redwoods are as 
   large and larger than any trees that have ever existed on Earth. 
   It is still not known how they are able to transport water all the 
   way up from the roots to the crown.  Wouldn't ancient trees have been 
   much larger than modern ones what with attenuated gravity and all? 
 
 
        Enough pointless blathering for now... 
 
 
                                                 - GECKO 
 
 
gecko@zooid.guild.org 
 
Xref: sparky talk.origins:9019 sci.skeptic:13486