What drove bird evolution?

It's another square/cube thing. Weight is proportional to volume which is a cubed figure, while the ability to fly is ultimately ralated to surface area of wings, which is a squared figure.

Adrien Desmond put it this way:

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"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 maneuver 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 lb.: Pteranodon and its slightly larger but lesser known Jordanian ally Titanopteryx were therefore thought to be the largest flying animals."

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The "were thought to be" was, of course, before things like the argentinian teratorn and the Big Bend pterosaurs were discovered.

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you have a picture of an ica stone on the top of your page. look for the thread on those here... they're known forgeries.

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The ica stones are not forgeries. The original discovery involved several tens of thousands of the things; nobody ever did that much work on the off chance that gringos might be willing to buy all of them, i.e. on pure speculation. Carving one of those things would take weeks and God knows what it would take to carve one and then try to make it appear ancient as they all do.

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you also have a link to the hava supai pictograph, which looks nothing like any dinosaur that ever lived, but vaguely like an 19th century mangling of an iguanodon skeleton.

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To most people it looks like a sauropod dinosaur. The web site also links to other images of known dinosaur types, such as the sauropod dinosaur at the state park in Utah: edited to fix page width - The QueenThis message has been edited by AdminAsgara, 07-16-2004 11:17 AM

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So not alone are you very ignorant of Evolution; rather simple physics concepts also escapes you. Should I conclude that you really don't know ANY science?

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Don't act surprised when you find your comments being ignored...

The debunking debunked:http://members.cox.net/...book-disputing_the_hoax_claims.htmI mean, I've posted this here before. To go on claiming that these stones are forgeries is basically dishonest.

CSICOP debunked (exposed as an ideologically committed witch-hunt organization) by one of its founding members:Starbaby

>And what does this have to do with the particular issue?It has to do with the squished frog citing CSICOP sources as proof that the Ica stones are forgeries. That's the post above my two.

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well, it doesn't look like a sauropod to me. they didn't stand that way, heads raised and dragging tails. they balanced head and neck against the tail, and both remained more or less straight out from the body.

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A book on Indian rock art sold at the Utah State Park park visitors center notes:

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There is a petroglyph in Natural Bridges National Monument that bears a startling resemblance to dinosaur, specifically a Brontosaurus, with a long tail and neck, small head and all." (Prehistoric Indians, Barnes and Pendleton, 1995, p.201) The desert varnish, which indicates age, is especially heavy over this section.

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There were two basic types of sauropods, i.e. brachiosaurids and the diplidocids. Simply from the bone structure, the former appear to have held their necks and heads upwards, the later outwards.In our gravity, of course, neither would be possible. A sauropod holding his head upward would be impossible because of the blood pressure requirements to get blood to a brain 40' above its heart and holding his neck outwards would be impossible because it would involve hundreds of thousands of foot pounds of torque.

>But the article you posted is talking about the Mars effect.Once somebody's been shown to be an ideologue and a liar, you don't have to go on checking his pronouncements...

Mechanical cranes have the structural support (cables) to handle large torque loads. A sauropod dinosaur's neck did not.

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That's simply a false claim. Sauropod necks did indeed have structural cables to handle those torque loads. They're called "tendons."

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Take a look at the cranes, the difference is pretty obvious. The tendons would have to be attached to a bone spur ten or twelve feet over the top of the dinosaur's shoulder for that to work.

The problem might be a little easier to comprhend looking at something other than a best possible case. The seismosaur's neck probably weighed between 30K and 50K lbs, and the center of gravity of that neck would have been 15' - 20' out from the shoulders. That's too much torque. No building inspector in America could be bribed sufficiently to let you build something like that out of structural materials, much less flesh and bone.To support that much weight, you'd need supports on both sides and the neck piece would have to arch upwards. The seismosaur's neck arches the wrong way, i.e. downwards, and is only supported on one end. In our gravity, that can't work.

You'd have to do a volumetric study to get a realistic weight estimate for the seismosaur's neck but, visually, you can line up three to five 10,000 lb elephants alongside the guy's neck and figure 40K lbs and you're probably ballpark. Having the cog of the neck 15' from the shoulders would also be conservative ballpark. That would be 600,000 foot pounds of torque.When I first noticed that, I tried to come up with something to compare it to to try to visualize it. I spoke with the people who service tanks and tank-tow vehicles at Aberdeen, i.e. how much torque is there on anything on a tank or tank-tow vehicle, and the answer was around 600 - 1000 foot pounds. I asked people at shipyards, how much torque was there on any sort of a nut which held a propeller on a large ship; couple thousand foot pounds...The only thing I could come up with with torque in the hundreds of thousands of foot pounds like that would be the combined total torque of all engines of a very large ship. For instance, max total horsepower for an Iowa class battleship, all four engines, is given as about 200,000 hp. If you use the normal formula for torque, i.e. (Horsepower * 5252) / RPM and assume maximum HP on one of those ngines is around 2500 rpm, which is a pure guess since I've not found figures for it, you'd be looking at 420160 foot pounds. That would be the maximum combined total torque of all four engines of an Iowa class battleship. That would be the torque needed to drive one of those ships through the water at a bit better than 30 knots.Now, the seismosaur looks big standing next to people, but not standing next to an Iowa class battleship. Having that kind of a torque load hanging off his shoulders 24/7 is not a ticket for success in life, or for dominating the world for tens of millions of years, as is claimed.

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hearts. plural. they think brachiosaurus had about 8 of them, and all pretty large. this was an animal adapted to reaching the highest branches. and either way, the blood pressure study has been done, and it's not problem.

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I'm not aware of any animal with more than one heart and I'm not aware of any scientific literature backing that sort of claim. Conversely, statements to the effect that there would be an insurmountable problem with sauropods holding their heads high are easy to find in real scientific literature.