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Member (Idle past 5260 days) Posts: 766 From: Newcastle, Australia Joined: |
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Author | Topic: Dinosaurs and the reduced felt effect of gravity | |||||||||||||||||||||||||||||||
RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
see swing bridge.
(add by edit):http://EvC Forum: Dinosaurs and the reduced felt effect of gravity [This message has been edited by RAZD, 04-19-2004] we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Some results of studies of strengths and structure:
Robert T. Bakker, "The Dinosaur Heresies" William Morrow and Company, Inc All dinosaurs had bigger cneimal crests than do elephants, even those groups with relatively straight hind legs -- the giant horned dinosaurs, stegosaurs, and brontosaurs. When these systems of oversized knee muscles contracted, the power exerted on the hind paw would have had no equal today. In addition, the attachment point on the pelvis for the knee extensors is the "ilium", and it, too, is of exaggerated size relative to mass in dinosaurs. Bakker shows the relevant musculature of a ceratopsian leg in a diagram (seen here). Bakker's position is, the cross section of tendon attachment points implies that dinosaurs limbs were subjected to forces equivalent to those running and walking in 1g. It is rather direct evidence against there having been any lower "felt effect of gravity" as Ted claims necessary. Hokkanen, J.E.I., 1986. "The Size of the Largest Land Animal" Journal of Theoretical Biology, v.118, p.491-499. Abstract: The upper mass limit to terrestrial animals is studied using physical arguments and allometric laws for bone and muscle strength and animal locomotion. The limit is suggested to lie between 10^5 and 10^6 kg. A possibility for a still larger mass, in case of new adaptations, is not excluded. 100,000 kg would be 100 tonnes (~220,000 lbs or 110 tons english, short).
Palaeos Vertebrates 330.200 Sauropodomorpha : Sauropoda
(indent in original) Sauropods were long believed to be semi-aquatic swamp wallowers, relying on the bouyancy of water to support their massive bodies. But analysis of their skeletons, in comparison with those of large terrestrial and semi-aquatic animals, and of sedimentation where their fossils have been found, show that sauropods were fully terrestrial:
"The deep thorax of sauropods is an adaption to problems of terrestrial weight-bearing. Sauropod foot and limb structure is generally comparable to elephants...(S)edimentological evidence does not suport immersion in deep lakes as....frequently pictured..."
[Walter Coombs, p.1] Not only were sauropods as terrestrial as elephants, but fossil trackways indicate that they lived in herds, again like elephants today. It must have been a truely awesome sight to watch a herd of brontosaurs crossing a Mesozoic floodplain; evoking the same sense of awe, and puniness in one's own being in comparison, as one would feel when observing whales close up. The Sauropoda include the largest animals ever to walk on land. These gigantic herbivores reaches lengths of 15 to 25 metres or more (the very largest may have reached 45 metres) and weights of 15 to 30 or even 50 or 60 tonnes. Previous estimates of 87 to 150 tonne animals are unrealistic and physiologically impossible. No sauropod ever equalled in size the greatest of the baleen whales. Well within the upper limit of structure 100 tonnes. Not just able to stand, but able to run, and some scientists think the sauropods cracked their tails like whips (but that is a different matter). Notice specifically that it was the structural analysis that showed the sauropods could stand unaided in 1 gravity that revised thoughts on where and how they lived, from swamp animal to dry land wanderer. Enjoy. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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redwolf Member (Idle past 5791 days) Posts: 185 From: alexandria va usa Joined: |
That's right. The human would be a LOT stronger, at equal weight sizes. More than half of the human's body weight is in bone and muscle in the legs, i.e. lefting/standing power. That figure for the sauropod, visually, would appear to be more like 10% or 15%
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
Presumably this same scaling has been done to compare the human weightlifter with the elephant to verify that the scaling used exactly predicts the bone sizes for the elephant and that extras like oversized cneimal crests are not necessary for the elephant to stand and walk.
btw -- unanswered posts now come toEvC Forum: Dinosaurs and the reduced felt effect of gravity http://EvC Forum: Dinosaurs and the reduced felt effect of gravity http://EvC Forum: Dinosaurs and the reduced felt effect of gravity http://EvC Forum: Dinosaurs and the reduced felt effect of gravity http://EvC Forum: Dinosaurs and the reduced felt effect of gravity http://EvC Forum: Dinosaurs and the reduced felt effect of gravity which I take as complete inability on your part to refute them. enjoy. we are limited in our ability to understand by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}
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redwolf Member (Idle past 5791 days) Posts: 185 From: alexandria va usa Joined: |
>btw -- unanswered posts now come to
Like I say, I try to reply to intelligent posts and questions. The others I don't feel any particular obligation to respond to.
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NosyNed Member Posts: 8996 From: Canada Joined: |
Like I say, I try to reply to intelligent posts and questions. The others I don't feel any particular obligation to respond to.
LOL. we have, you know, seen this before. You are not fooling anyone.
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RAZD Member (Idle past 1405 days) Posts: 20714 From: the other end of the sidewalk Joined: |
It's okay, I understand. There may be more to it.
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1.61803 Member (Idle past 1504 days) Posts: 2928 From: Lone Star State USA Joined: |
I think that pretty much covers it Abby. Unless wolf can dredge up another few pictographs of mythological beast posing as dinosaurs, or dinosaurs posing as weight lifters, or elephants posing as bridges. His reduced gravity theory has been reduced to CA-CA.
"One is punished most for ones virtues" Fredrick Neitzche
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crashfrog Member (Idle past 1467 days) Posts: 19762 From: Silver Spring, MD Joined: |
What is being ignored in that theory, of course, is torque. Here's a picture of a typical urban construction crane: The arm of that crane is considerably longer than any sauropod's neck, not to mention heavier, especially loaded. So according to your argument the torque involved must be intense - hundreds/thousands of times what you claim it must be for the dinosaur. Now, I'm looking, but I just can't find the hundreds of battleship engines holding the arm up. Can you point them out to me? Thanks.
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Dr Jack Member Posts: 3514 From: Immigrant in the land of Deutsch Joined: Member Rating: 8.7 |
Way to not get the point - it's not about muscle mass, it's about mechanical construction. Humans are mechanically pretty weak, Sauropods are mechanically constructed to move with enormous loads.
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JonF Member (Idle past 168 days) Posts: 6174 Joined: |
The idea that you can simply scale up a human weightlifter is non-sensical. Humans simply do not work in a mechanically comparible way to a sauropdod.
That's right. The human would be a LOT stronger, at equal weight sizes. And they would be totally incapable of functioning. Their bones would not be able to withstand the stress of their weigjht and the forces of their muscles. You cannot scale any organism up or down by a significant amount and get a functioning version.
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Coragyps Member (Idle past 735 days) Posts: 5553 From: Snyder, Texas, USA Joined: |
You cannot scale any organism up or down by a significant amount and get a functioning version.
Despite protestations at certain "creation science" museums to the contrary: they have a five-foot long "human femur" in scenic Crosbyton, Texas:Page not found – Mt. Blanco Fossil Museum
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redwolf Member (Idle past 5791 days) Posts: 185 From: alexandria va usa Joined: |
That's interesting. It looks like the ossified generation no longer has any sort of a hammerlock on paleontology.
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redwolf Member (Idle past 5791 days) Posts: 185 From: alexandria va usa Joined: |
Herre's yet another piece of the picture which I seem to have overlooked here. The heaviest birds which can take off or land in our present world are around 30 lbs, including albatrosses and buzzards, and the largest flying eagles are around 25 lbs, i.e. the largest berkuts. They get one or two berkuts that size every fifty years or so; any larger than that, and they can't take off or land, and they perish. The Argentinian teratorn, of course, was a 200 lb eagle with a 25' wingspan, yet another thing which can't happen in present gravity:
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TechnoCore Inactive Member |
There are some implications when scaling creatures you haven't thought of. When you scale something up, the mass increases faster than the area. Mass defines load, and area will define the load bearing ability.
When load increases faster than load bearing ability, we have a problem! If you scale up a building by 10 times, it will get 1000 times heavier but it will only get 100 times stronger. Lets see what happens if we double the size of a human ?Mass scales with the cube of the linear dimensions: Doubling his size will also make him 8 times heavier. Lifting power scales with the square of linear dimension.This means that the man above will be 4 times stronger than before, but weigh 8 times more, making him only half as strong, not stronger as you stated. (He will barely be able to stand) The surface area to mass ratio scales with the inverse of the linear dimension. He will have real big problems trying to get rid of body heat. He'll die from a feaver within minutes. The cross-section of the blood vessels will roughly scale with the square of linear dimension. This means that 4 times as much blood can be pumped through the body, but there are 8 times as many cells to feed. So only half of them can be fed. And on top of that the blood-pressure will be halved since the heart is a muscle. It won't be able to pump blood up to the brain. The bones in the body will roughly scale with the square of linear dimension... you get the idea... they will break more easily. So in order to scale something up, you need to construct it in a complete different way.
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