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Re: On why I think that Hutchinson & Garcia *might* be correct...



OK. Here are my final, end all be all thoughts on the subject. I promise.

Holtz writes: 

>>Actually don't know much about their experiments, but a series of recent 
>>papers (some of which were published in American Zoologist about a year or so 
>>ago, in their Axial Skeleton issue) suggest that helical fibers of various 
>>tissues (blubber, among other things) are very important "springs" in the 
>>locomotion of fast swimming vertebrates.<< 

Ah.... See, that is the type of stuff I&#8217;m talking about... The 
unavoidable fact that it all breaks down too is that you can get errors in your 
models of animals that contain assumptions based on a premise that is not 
questioned unless living examples are there to contradict it. Living examples. 
That&#8217;s the key... and it&#8217;s the key we woefully lack in 
Dinosaurology. Nothing like multi-tonne theropods exist today, and this already 
puts you at a huge disadvantage when modeling. In fact, nothing like dinosaurs 
are around today... Period... When modeling these animals, you have to resort 
to plugging in educated assumptions that can never be verified... that can 
never be observed... that can never be tested... At best, we are left with 
approximations with error bars. That's how you do good science. This is pretty 
much the underlining sentiment that I see coming from Hutchinson&#8217;s paper. 
That is what makes his work such a breath of fresh air. Thanks Mr. Hutchinso!
!
n. :-)

So, the situation we have is one of the valid excuse, repeated over and over 
again on this mailing list and in papers and in books, which states that we 
can&#8217;t know anything for certain about any of these animals because we 
seriously have no living representatives close enough to them to compare our 
models, theories, and ideas too... Why should the question of their locomotion 
be any different???...  This is worse than the situation we have with modeling 
star systems... and with them we are just talking about cut and dry physics 
folks... Gravity and particle interactions... Not complex biological 
dynamics.... We can&#8217;t even model binary star systems correctly, let alone 
triple and quadruple, and they obviously exist. They are the most common star 
configurations in the universe!!!

I know that you need to be able to do models that need to work for both extinct 
and living animals. But when is comes to the big picture, I see that there is 
just more to theropod locomotion then the musculature of chickens and 
crocodiles and mammals... How could anyone deny that? I&#8217;m not saying that 
they were alien beings or anything... Gravity hasn&#8217;t changed and the 
speed of light is still as constant in a vacuum today as it was back then. 
Dinosaurs were just built like nothing alive today. It makes me smile to see 
that the helical fibers of various tissues are important springs in the 
locomotion of fast swimming LIVING vertebrates... And as the studies said, this 
is only suggested!!! We don&#8217;t even know this for sure! Yet, here we are 
modeling the locomotion of animals that have NO modern representatives to cross 
check our work on....

Just think of the world of hurt those that study fossil felids would be in, if 
when trying to figure out how a _Smilodon_ used it&#8217;s sabers, they 
didn&#8217;t even have modern cats to observe moving,... Let alone hunting and 
killing.... That&#8217;s right.... They would be in the same desperate 
situation Dinosaurology is in.... Even with the cats for them to watch, it took 
over 150 years to finally model the use of the sabers in an apparently proof to 
life way and people are still arguing about it. Such are the trials and 
tribulations of Science. You gotta love it!!! :-)

I mention only in passing that I think that it could very well be that these 
springy tissues present in fast swimming vertebrates who have been modeled to 
show that they apparently lack the muscle power to move as they do... are 
analogous to the tendons and the cartilagenous joints of theropods who by 
Hutchinson&#8217;s model apparently lack the muscle power to move as fast as 
some think that they could move. Anyone know every single one of the 
characteristics of tyrannosaur tendons and cartilage??? No one does. And no one 
ever will. Yes, the same biology applies to them as it does to birds or what 
have you, but owing to the fairly complex geometry of the leg joints, and the 
physiological properties of the muscles and tendons, assumptions on the 
energetics and the accompanying locomotion are not strictly valid. More 
accurate data is obtained by experimental measurements made using high-speed 
photography and other such monitoring and recording equipment... Never mind 
that there!
!
 is more too it then just the anatomy... You need the actual observation of the 
animal in question.

As I said... To me, it&#8217;s the pogo stick. Instead of the "swoosh swoosh 
swoosh" of the tail that belongs to the multi-tonned whale moving happily along 
at 25 miles and hour... it's the "bounce bounce bounce" of the legs that belong 
to the multi-tonned tyrannosaur moving happily along at 25 miles an hour. Yes, 
it is true that you can have substantial variation in locomotor speeds as a 
function of substrate type (water vs land). Moving in water is more efficient 
then running around on land. But, I&#8217;m speaking about two completely 
different animals, with completely different adaptations that have evolved to 
make them as efficient as possible in their perspective environments. Muscles, 
and springy tissues in multi-tonned whales. Muscles and springy tissues in 
multi-tonned dinosaurs. But hey... Biomechanics is something I need to learn 
more about, so I mention things only in passing.

My degree is in Physics. Not anatomy... I am sure my lack of knowledge shows... 
even in both areas.... So, I could be completely wrong in everything I say... 
I'm sure I'm way off about many things. I&#8217;m no expert like some of you, 
but I know enough to sit and make some passing observations that I think are 
worth at least something.


Kris

PS. Yes, I know... You can pawn off all of what I just wrote on being nothing 
but wishful thinking. :-)

PSS. This is a question for everyone. I feel really odd not knowing how to 
refer to you. Should I call you by your last names? First names? Doctor???? I 
just don&#8217;t want to be disrespectful. :-)