gravity and dinosaurs

December 6, 2007

No disrespect, Dino, but balance is more a factor than the number of legs. Bipedal dinosaurs had large, heavy tails which were used as a counterweight around the pivot of their legs. While we see many large, bipedal dinosaurs this is only relative to our perspective of 'large'. The truly large dinosaurs were all quadrupeds. As I suggested to Fabrosaur, if you want to suggest bipedalisim supports paleogravity you'll have to show how the stresses on a large bipedal dinosaur (such as hadrosaurs or the large predators) would be too great for the animal to support in a 1g environment. If you can't show that then statements such as 'bipedalism supports paleogravity' are simple speculation and non-educated opinion (I don't mean non-educated as in anyone is uneducated, I mean not validated by actual data).

The only way to say that the larger size of the dinos is irrelevant to gravity is to say that they were almost certainly made out of some kind of super stuff uncommon to animals today, and that evolutionary development of this stronger flesh was such a rare and wonderful accident of nature that: closely related modern animals (birds, crocodiles) cannot re-evolve it. I think it is far safer to assume that if gravity changes, then whatever life forms are pre-existing will naturally evolve to scale up or miniaturize on down. They will distribute their weight among a different number of limbs. The maximum-sized skyscraper that you would be able to build would change. The maximum height that a tree could grow would change. Of course animals would too. Why wouldn't they? Dinosaur size fits the paleogravity picture in the most obvious way, moreso than the fact that the only surviving line (birds) have hollow bones to reduce their weight. For the purpose of flight, yes, but that is still as relevant as the fact that their closest living relatives (crocs) now bask in the neutral buoyancy of fresh water. This is how we would have expected to see a gravity-driven selective process to influence the animal kingdom, and this is what is reflected by the big-picture evidence.

Where is the evidence deep ocean trenches did not exist pre-Pangaea? The theory of continental drift implies it is a continuous process and did not start with Pangaea, but began billion of years before that, perhaps even as soon as the Earth cooled enough for continental plates to form. The continents being consolidated in a single landmass does not imply there is not plate subduction happening in areas where plates meet under the unified ocean. I'm afraid you are trying to make the theory fit your conclusion, not the other way round.

Ow, good one. It is incorrect to say, "there may have been... many deep ocean floor trenches opening up where there had previously been none." How about this: Whatever force for the creation of deep sea trenches existed before the Pangea break-up, more of such force probably existed during and afterwards."

And to answer Fabrosaur, I callenge that scientists know that there has been no net loss of sea floor, and that studies were done to make sure. I don't think anyone thought that such a study was needed, but I'd better get my read on before I say any more on it. And no ice caps at the time, huh?

Edited December 6, 2007 by dinotheorist

December 6, 2007

Fabrosaur and Dino,

I will refer you both again (fabro for the first time actually) to the article at TalkOrigins which specifically shows, by using biomechanics, that dinosaurs were quite capable of attaining the size they did in a 1g environment. We have a much more accurate picture of hadrosaurs now that this newest fossil has been found so you can apply biomechanics to show whether your paleogravity idea is required for their locomotive abilities given their size. As I have said - a few times now - it's no good just speculating reasons, such as 'super-stuff tissue' to try to disregard a normal (1g) gravity environment...you have to show how it is not possible. Use biomechanics, analyse and calculate the stresses involved - no, Fabrosaur, we don't need a living hadrosaur provided we have an accurate enough idea of their general anatomical structure, which this new fossil should give us.

Whatever force for the creation of deep sea trenches existed before the Pangea break-up, more of such force probably existed during and afterwards.

Again, Dino, I'm sorry but this reasoning doesn't make sense. Continental drift doesn't 'stop' or 'slow down' during supercontinent phases, it is a continuous process. I don't think you will be able to use continental drift to explain ocean levels rising and falling.

Edited because I forgot the link!!!

Edited December 6, 2007 by Leonardo

December 6, 2007

Fabrosaur and Dino,
I will refer you both again (fabro for the first time actually) to the article at TalkOrigins which specifically shows, by using biomechanics, that dinosaurs were quite capable of attaining the size they did in a 1g environment. We have a much more accurate picture of hadrosaurs now that this newest fossil has been found so you can apply biomechanics to show whether your paleogravity idea is required for their locomotive abilities given their size. As I have said - a few times now - it's no good just speculating reasons, such as 'super-stuff tissue' to try to disregard a normal (1g) gravity environment...you have to show how it is not possible. Use biomechanics, analyse and calculate the stresses involved - no, Fabrosaur, we don't need a living hadrosaur provided we have an accurate enough idea of their general anatomical structure, which this new fossil should give us.

Again, Dino, I'm sorry but this reasoning doesn't make sense. Continental drift doesn't 'stop' or 'slow down' during supercontinent phases, it is a continuous process. I don't think you will be able to use continental drift to explain ocean levels rising and falling.

Edited because I forgot the link!!!

I looked at the link you provided. I don't know anything about Wayne Throop but I believe he is missing the forest from the trees.

It is totally irrelevant whether the largest known African bush elephant is 16,000lb, 20,000lb, 24000lb or somewhat higher. We could quibble about the maximum weight a human being could attain. Is it 1000lb, 1100lb, 1200lb, etc?

What is the maximum weight of known sauropods? With the logic that you are using, an elephant could, barring any environmental constraint (excepting gravity), attain the same weight. I say, no way.

I'm not passing judgement on the Holden Limit, the Holden Number, etc. I'm saying that the known maximum size of animals, when there are enough to arrive at a reasonable sampling, whether they be elephants, humans or any other, provide a good indication of the maximum size attainable for a specific gravitational value.

Your comment on continental drift and sea level is not accurate. Actually the term "continental drift" has been replaced with "plate tectonics." When there is rapid creation of ocean crust at the ocean ridges, there is corresponding transgression on the continents because the rising upflow is very hot and expanded and displaces water onto the continents. Likewise, when the that process slows down, it cools down and the effect is regression.

December 6, 2007

When there is rapid creation of ocean crust at the ocean ridges, there is corresponding transgression on the continents because the rising upflow is very hot and expanded and displaces water onto the continents. Likewise, when the that process slows down, it cools down and the effect is regression.

Yes! I asked the following question on Yahoo!Answers:

Is it true that glaciers are known NOT to have been forming in the millions of years leading up to the K-T? ...Even though the Deccan volcanism was going on, which one would think would reduce the sun's rays reaching the Earth, and ocean levels were dropping?

mountaingym answered:

"It's true. The Cretaceous was known for its hot and humid climate. I have not heard of any glaciation in the Cretaceous Period or the Mesozoic Era."

Link to the question:

<a href="http://answers.yahoo.com/question/index;_y...05170933AARHHTb" target="_blank">http://answers.yahoo.com/question/index;_y...05170933AARHHTb</a>

If it's not glaciation that's causing a drop in ocean level, then what the heck is it? Obviously major changes in the shape of the Earth's crust are likely to change the capacity of the ocean, and affect sea levels.

And as far as having to show how the size of dinos "was not possible" in 1G, I (for one) am not saying, "impossible." Anything is possible.

I'm saying that paleogravity does not require 1G dinosaur weight to be impossible. It only has to make 1G dinosaur weight less practical in order to affect the direction of animal evolution. And, a new environmental stress doesn't have to be so dramatic that it sends a horde of mighty beasts crashing to the ground all in one dramatic day to cause extinction. It only has to curtail the reproductive success of one group of animals against competing groups of animals over long stretches of time, perhaps until a routine cataclyzm (such as a meteor impact) causes the prevailing evolutionary results to play up. That's what is reflected in the fossil record. There are not fossils that point directly to the dinosaurs' killer, such that a bunch of CSI investigators would have fun with, analyzing a big skeleton for the evidence. Fossils from 70-65 mya show dinosaurs dying from the same stuff they always died from throughout the Mesozoic. That's because changes in the reproductive success of an animal do not show up in fossils. There is only a change in the frequency in the occurrence of the fossils -- that is the evidence. Paleogravity fits that body of evidence.

It is a more difficult evolutionary feat for an animal to develop extremely large size, than to stay within bounds that do not so much challenge the constraints of physics. That's all it takes. When we say that dinosaur gigantism seems utterly improbable for land animals in 1G, we are in good company with all the scientists of past decades who believed they must have been swamp creatures. These scientists' points of view were validated by years of study, observation, and analysis -- even if they were wrong about the neutral buoyancy explanation. They had a point. There's nothing uneducated about taking another look at their way of seeing dinosaurs and saying, "maybe there is another way besides neutral buoyancy that explains why they were so large."

Edited December 6, 2007 by dinotheorist

December 7, 2007

There are a few crocodilians which evolved the ability to live as land predators after the dinosaurs, proving that it was possible for them to do so. But by the same token, what stroke of bad luck kept them from rising to dinosaurian glory? My argument is that it wasn't bad luck at all. It is no longer "profitable" enough for a dinosaur-like animal to "make its living" as a large land animal -- at least, not against the contemporary mammal competition.

That's what I put in one of my posts some time ago, and it so happens there's been a discovery in the Bahamas of one of these crocodiles -- it apparently lived there as recently as the arrival of humans.

Here's a link to a pic of the skull, where you can click to the corresponding news article:

http://www.livescience.com/php/multimedia/...amas%20Sinkhole

December 12, 2007

The original posts reminds me of Pandas. They sleep all day, roll when they need to go somewhere, and spend hours upon hours eating. It made me imagine dinosaurs in a new way. Panda's too are one of the oldest animals on earth. Nice thread.

I can imagine dinosaurs being heavy and lazy lol.

February 20, 2008

Hello, all. I joined, I must confess, just to ask a simple question of you all; particularly of Dinotheorist but it does relate to others. My question is, simply, are you all willing to concede that statements such as

"Another way of saying that dinosaurs appear to have been too large to support their body weight is this: that dinosaurs appear to have been lower-gravity organisms." - (www.dinotheorist.com)

are based on a false premise (and the above then follows on with a false dichotomy) and not supported by actual evidence but, in fact, are in direct opposition to current science? Are you willing to concede that the general consensus amongst scientists who are seriously studying the matter, in paleontology, biomechanics, etc. is that dinosaurs were quite capable of supporting themselves and locomoting on a 1G Earth? And, further, are you willing to cease implying (or outright stating) otherwise?

This link, http://www.talkorigins.org/faqs/sauropods.html , has come up a few times here, but I would also point you to:

http://www.ucmp.berkeley.edu/diapsids/saur...nosauridae.html

wherein T. rex is described to be a "fairly fast" runner at 10-20 MPH.

And Manchester University has recently backed up these assertions when modeling five separate meat-eaters, finding that they basically agreed on T. rex speeds (they also found that Compys may have been able to run at a staggering speed of nearly 40MPH!). No one argues any longer that Apatosaurus, for instance, had trouble supporting their weight and that they did indeed graze and herd. And while they may not have been much for running, they weren't exactly immobile. And... a 75 foot 25 ton animal with a multi-ton whip-like (literally, according to some) tail really isn't an ideal target for most predators.

Also, I'm perplexed by the number of arguments I commonly find on the net where a dinosaur's speed is argued as 'slow' but the relative context of their peers and prey isn't taken into consideration. "Slow" is an entirely subjective pronouncement (comparisons to humans and other non-relevant animals is... pointless, I think we can agree?). A T. rex running flat out may indeed have a chance of catching a hadrosaur, for example, which has a top speed which is 5 - 10 MPH faster but who may not be as quick in a sprint (which is another thing to consider in the argument that higher gravity supposedly necessitates more supporting limbs - gravity is not all that's in play here) and tend to herd. And it may have had a very good chance of snagging one of us in our current chair-dwelling configuration.

But I digress... it's the first question I'm most keen to see any answer on. Dinotheorist, others, are you willing to concede this?

Thanks for your time.

February 23, 2008

In the interest of fairness I should mention that, since I haven't heard a response, I went ahead and blogged about my issues with Dinotheorist's ideas.

http://www.gwangivalley.com/2008/02/23/run-rex-run/

(Someone asked why I wouldn't do this via e-mail. The reason is that I don't like having these sort of discussions 'off the record', so to speak. That's why I came here first.)

I'm still keen to hear any responses.

Edited February 23, 2008 by gwangivalley

February 23, 2008

Hi gwangivalley, and welcome to UM.

I'm not sure if dinotheorist or Fabrosaur are still around but I'm glad you asked the question of whether their views are fixed or they are truly considering this topic from an investigative pov.

One further issue I have with the paleogravity theory is it's assumption that the Earth has been contracting over it's entire history so surface gravity should have been increasing in each geological age, yet dinosaur species actually grew more massive from era to era of their [dinosaurs] existence. This would seem to be contrary to what the theory proposes and indicates this theory does not, in fact, consider conditions from the beginning of the planet, but is a 'gap' theory attempting to explain a bounded scenario without thought to the theory's implications on preceding ages of the planet.

Edited February 23, 2008 by Leonardo

February 24, 2008

I couldn't agree more, Leonardo. The very fact that the largest pterosaurs, for instance, appeared at, not the beginning, but the end of the era suggests a fundamental flaw in the notion (and let not the casual reader forget, we're talking about millions of years here). These are animals whose very livelihood was tied to gravity and atmospheric density. Tie that with the fact that the giant insects of these ancient eras could not have lived in a lower density atmosphere. We know quite certainly that the oxygen content of the atmosphere was around 30% higher than today when these huge bugs were around. This oxygen richness __inside a dense atmosphere_ was critical to these giant insects existence because it allowed them to respirate _at all_ via their tracheal system. A lower gravity does not allow for such an atmosphere to exist.

I'd very much like to see this... well, I now consider it to be in the "old wives' tale" category.... this falsity routed out of popular notion. It does nothing but confuses the issue for those attempting to learn or explore and clouds the water for those who haven't sought to test out information on their own (especially those who take "I once heard" notions as factual).

February 24, 2008

I couldn't agree more, Leonardo. The very fact that the largest pterosaurs, for instance, appeared at, not the beginning, but the end of the era suggests a fundamental flaw in the notion (and let not the casual reader forget, we're talking about millions of years here). These are animals whose very livelihood was tied to gravity and atmospheric density. Tie that with the fact that the giant insects of these ancient eras could not have lived in a lower density atmosphere. We know quite certainly that the oxygen content of the atmosphere was around 30% higher than today when these huge bugs were around. This oxygen richness __inside a dense atmosphere_ was critical to these giant insects existence because it allowed them to respirate _at all_ via their tracheal system. A lower gravity does not allow for such an atmosphere to exist.
I'd very much like to see this... well, I now consider it to be in the "old wives' tale" category.... this falsity routed out of popular notion. It does nothing but confuses the issue for those attempting to learn or explore and clouds the water for those who haven't sought to test out information on their own (especially those who take "I once heard" notions as factual).

Hello qwangivalley,

In response to your skeptical view of the possibility of a lower paleogravity I would reply:

1. You are right about the largest pterosaurs evolving later than the smaller ones. I believe this happened exactly for the reason we are talking about.....gravity was increasing then. In order for those smaller pterosaurs to survive they had to "solve" the increasing gravity problem. They did this by increasing their wing area to mass ratio. So, what seems like a contradiction with a larger pterosaur succeeding a smaller one isn't really a contradiction at all.

2. The circumstantial evidence of the lower paleogravity is substantial. The life forms that were gigantic relative to today is enormous. Just look through the threads on this website. Recently there was a post on the giant "Devil Toad" which is reportedly to have been 10 pounds, 16 inches long. There were clams six feet in diameter and you know how big some of the largest dinosaurs were.

You have to ask yourself how this could have happened. Even if no one can give you a satisfactory answer, that doesn't falsify the premise of a lower paleogravity. Also, I don't believe oxygen levels were a deciding factor because, as I mentioned, there were clams and other marine life that were also gigantic.

February 25, 2008

Sorry it took so long to reply, I have had an ongoing family emergency.

Hello, all... statements such as
"Another way of saying that dinosaurs appear to have been too large to support their body weight is this: that dinosaurs appear to have been lower-gravity organisms." - (www.dinotheorist.com)

are based on a false premise (and the above then follows on with a false dichotomy) and not supported by actual evidence but, in fact, are in direct opposition to current science? Are you willing to concede that the general consensus amongst scientists who are seriously studying the matter, in paleontology, biomechanics, etc. is that dinosaurs were quite capable of supporting themselves and locomoting on a 1G Earth? And, further, are you willing to cease implying (or outright stating) otherwise?

Concede? No, I actually feel pretty good about what I said.

In the interest of fairness I should mention that, since I haven't heard a response, I went ahead and blogged about my issues with Dinotheorist's ideas.
http://www.gwangivalley.com/2008/02/23/run-rex-run/

That's fine, I'll read that too after I finish this reply.

The “false premise” that dinosaurs were too heavy to support their weight was believed by generations of educated men who dedicated their lives to studying dinosaurs. I mention it because -- yes -- it supports my arguments, which I concede are far less humble than my unfinished biology degree.

Modern researchers ARE continually stacking new evidence that:

> Dinosaurs were NOT swamp animals who relied on the neutral buoyancy of water for support of their body weight. They occupied the role of land animals.

> Dinosaurs were highly active.

Scientists are not looking for, or continually discovering new evidence that dinosaurs lived in 1.00G. The question of gravitational definition is mudded/clouded by the suggestion that it is a reactionary idea, coupled with those old notions that were blown out of the swamp water by Bakker and others -- and therefore cannot be dignified by any consideration in the scientific community.

What I will concede is that IF my hypothesis turned out to be correct, it would be a most confounding thing that a biologist WITH a degree did not think of it instead of me. But, that sort of thinking didn't stop Gregory Mendel from discovering genes and it won't shut me up either.

The very fact that the largest pterosaurs, for instance, appeared at, not the beginning, but the end of the era suggests a fundamental flaw in the notion (and let not the casual reader forget, we're talking about millions of years here). These are animals whose very livelihood was tied to gravity and atmospheric density.

Yes, I have said that the largest animal that may evolve in any given gravity cannot be as large as the largest that may evolve in lesser gravity, for the same simple reason that a building or a tree could not be as large.

What I'm proposing is that within any geologic period that is puctuated by an increase in surface gravity, animals will continue to evolve larger and larger right up until the increase. Then, it is the largest animals which will suffer the worst from the increase. The largest sauropods, for instance (which died out at the end of the Jurassic) were succeeded by the cretaceous alamosaurs whose camarasaur-like physiology appeared to be a compromise between the brachiosaur design for sheer height, and the diplodocus family's features which allowed it to attain maximum feeding height by rearing back on its tail in a tripod stance.

That is not to set dinosaurs as a benchmark of maximum size to which no animal can ever evolve to be as large in 1.00 G. But, such an accomplishment would probably have to take place over MORE millions of years than before, require a more advanced genetic "state of the art," and is less likely to happen at all than in the mesozoic.

The fact that pterosaurs' "very livelihood was tied to gravity" is to say that they were HIGHLY SPECIALIZED to operate against gravity. Now here's where I would say, ADAPTED and SPECIALIZED are not exactly like terms. Birds are very well adapted against the force of gravity. So well adapted, in fact, that their flying mechanism folds onto their back and is tucked away so that the bird can temporarily function as a land animal. A pterosaur or bat on the other hand is so specialized against gravity -- its anatomy completely given over to the flight mechanism already -- that an increase in gravity would be more likely to ground it for good. And in the case of the pterosaurs, I say it did. Like a heavily-sponsored race car that can't fit one more decal on its frame, there was no room for further adaptation; the pterosaurs' flight technology was mature.

Tie that with the fact that the giant insects of these ancient eras could not have lived in a lower density atmosphere. We know quite certainly that the oxygen content of the atmosphere was around 30% higher than today when these huge bugs were around. This oxygen richness __inside a dense atmosphere_ was critical to these giant insects existence because it allowed them to respirate _at all_ via their tracheal system. A lower gravity does not allow for such an atmosphere to exist.

I appreciate the more-specific argument that a lower-G atmosphere would be less dense. As you said, the atmosphere was more oxygen-rich. However, Oxygen is heavier than the other abundant gas in the atmosphere: nitrogen. I conceded earlier that the change in ratios itself does not imply gravitational definition because the gases do not achieve escape velocity; only hydrogen in the outermost layer does that. But, the effect of reduced air pressure would be offset by the change in ratios.

Have paleoentomologists determined that the large size of ancient insects, with their greater ratio of body volume to body surface area, with their trachael respiratory tubes that reach every cell of their bodies like capillaries, allowing for their slower, open circulatory systems to forego the role of gas transport... that their larger size was only possible due to a denser atmosphere? I hadn't heard that, so by all means provide a or periodical reference for me to check out.

I'd very much like to see this... well, I now consider it to be in the "old wives' tale" category.... this falsity routed out of popular notion. It does nothing but confuses the issue for those attempting to learn or explore and clouds the water for those who haven't sought to test out information on their own (especially those who take "I once heard" notions as factual).

You know, you are free to personally consider my ideas however you like. I do not log onto this site with the intent to confuse anybody. I will read further into the relevant areas of science as my work schedule allows, and as my family emergency is hopefully resolved in the next couple of weeks. But as a working man with big stuff going on, I think I'm doing all right as far as maintaining an intelligent discussion here. I may not get the chance to reply quickly, but I'll reply when I can. And like other things in my life, I believe what I'm doing and saying, and not asking others to consider something that I believe in my heart is bogus. In other words, I'm not blowing smoke like Kevin Tredeau (sp?) just to make a name for myself.

My point of view is investigative, but investigation requires time that I don't have right this minute. Until I can, I will argue what I find to be arguable. The overall assumption that any groundbreaking new idea can only come from someone with a big degree and a government paycheck... I don't consider that valid.

February 25, 2008

Well, I checked out gwangivalley's blog...

http://www.gwangivalley.com/2008/02/23/run-rex-run/

and first off I would like to say I've been looking to have one of those and by golly, now I know where to go so I can have one. Wordpress.org, huh? Very cool.

What kind of traffic do you get on that thing? How do you promote it?

I have some specific counter-arguments all right, which I will get to in turn, what's the hurry?

Are you like, single?

February 25, 2008

I thought for sure there would be an argument for the lower gravity of the earth, as was proposed by the theorists of the expanding earth. At one time, it was proposed, the earth was smaller in diameter, and the gravity was correspondingly less. The expansion is blamed on sudden appearance of mass as created by fusion taking place in the planets core. This in turn is related to gravity being a form of influx from space of an "aether"/ether. Lots of work on this was developed by Ott C. Hilgenberg. These expansion periods were supposedly quite sudden, and with concomitant shrinking or "falling back", exactly the way plants grow. So goes the theory. Hilgenberg's model included much original work on plate techtonics, for which he gets little credit, and his ether theory also was used to develop a periodic table with elements up into the 200s. His method of developing atomic models presaged the stick-and-ball format, and was predictive, but just how successfully predictive, I can't say. However, his model was capable of being visualized, and he also gave some pretty interesting suggestions as to why the Michaelson-Morely experiment failed to show any relative motion of a "medium", since it was orientated entirely in the horizontal. His suggestion that a vertical component of the apparatus would have shown a significant differential. It is possible to assume that the "extinction" event that is currently attributed to a massive object impacting the earth was due to an expansion event, and that any impact of any object followed this, rather than precipitated it. Since the gravity was suddenly increased while the orb expanded, any object in space affected to move out of a stable orbit would now be attracted. It would also be possible to assume as the shell of the earth was fractured by expansion, more massive areas might slip much more quickly, or plate-movement would be accelerated, and this could explain a lot about discoveries of masses of living forms being collected together as if they had been in a blender. Velikovsky (sp?) gives many references to findings of tons of bones and flesh gathered together in niches in the mantle that are generally attributed to floods or what-not (and he attributed to the near-passage of a planet). Just another alternative theory impossible to test, but possible to apply to further speculations. There are so many different ways to fit the competing theories together, yet the urge to be absolutist about these individual theories defeats each one in many ways which might make sense if the different components were applied together with varying degrees of values corrected for time and allowing for change in gravity values. Most theory assumes gravity constant, with no rational rejection hypothesis. Interestingly, Hilgenberg's theories also provide for reasons to believe the speed-of-light constant has to be rejected as a "locality prejudice" since we can't be sure what the speed of light is outside the environs in which we measure it, that is, in a cosmic or galactic sense.

February 26, 2008

Hello qwangivalley,
In response to your skeptical view of the possibility of a lower paleogravity I would reply:

1. You are right about the largest pterosaurs evolving later than the smaller ones. I believe this happened exactly for the reason we are talking about.....gravity was increasing then. In order for those smaller pterosaurs to survive they had to "solve" the increasing gravity problem. They did this by increasing their wing area to mass ratio. So, what seems like a contradiction with a larger pterosaur succeeding a smaller one isn't really a contradiction at all.

2. The circumstantial evidence of the lower paleogravity is substantial. The life forms that were gigantic relative to today is enormous. Just look through the threads on this website. Recently there was a post on the giant "Devil Toad" which is reportedly to have been 10 pounds, 16 inches long. There were clams six feet in diameter and you know how big some of the largest dinosaurs were.

You have to ask yourself how this could have happened. Even if no one can give you a satisfactory answer, that doesn't falsify the premise of a lower paleogravity. Also, I don't believe oxygen levels were a deciding factor because, as I mentioned, there were clams and other marine life that were also gigantic.

Hello, Fabrosaur.

I have to say that your response 1. is a bit troubling as there's both no evidence to suggest such a thing and no reason to assume this was the case evolutionarily. You're asking to 'solve' a problem that doesn't exist. Selective pressures to grow large surely existed, because the animal grew larger, but there's no evidence to support the notion that gravity increase was among those pressures. Queztlcoatlus' wing area to mass ratio is much less favourable than its smaller, earlier brethren such as Thalassodromeus or Tupuxuara (A good chart to do the math from can be found in - Humphries S, Bonser RHC, Witton MP, Martill DM (2007) Did Pterosaurs Feed by Skimming? Physical Modelling and Anatomical Evaluation of an Unusual Feeding Method. PLoS Biol 5(8): e204 doi:10.1371/journal.pbio.0050204).

This sort of falls smack into point 2. Circumstantial evidence, of which I see very little, cannot hope to contend with physical, experimental and observational evidence in a fair fight.

Unless this circumstantial evidence is packing a knife. It had also best bring a pickaxe to break up and hide the sedimentary evidence which flows evenly and as expected in the geological record and never indicates this gravity difference.

And, I have to be frank, it's not up to me to 'falsify' lower paleogravity, it's up to you lot to falsify the evidence to the contrary as the case for this alternative theory is light enough to take flight in even the thin atmosphere we keep coming back to. Yet evidence against it is rather... weighty (no gravity pun intended).

The preponderance is upon you.

Extraordinary claims require extraordinary evidence.

When one claims that gravity change may have played a role in dinosaur extinction, one must being by answering the challenge of the scientific record which does not indicate anything of the sort took place.

And, forgive me... but what _is_ you boys' fascination with gigantism? LOL

Sure, there were giant things then and there are giant things now. There seems to be some notion that gigantism is an evolutionary goal. Every niche is not a large hole. But if one takes a 2 foot wingspan dragonfly-like insect and sticks it into our atmosphere, it will not survive. That's a point of a very fine nature. (as Dinotheorist rightly asks me to cite more in his response, I'm doing so here as well. See this story and associated papers which show recent studies bearing this out: http://www.sciencedaily.com/releases/2006/...61012093716.htm ). We know with a great degree of certainty the atmospheric makeup in question and there was definitely a higher oxygen concentration that allowed these insect to live (without the aid of respirators or oxygen tents). We also know how gases of a planetary body behave under different gravitational influences.

Lowering the gravity for the Mesozoic or the Cambrian would have a marked change on the Earth model and the inhabitants as observed. It would require us to set aside good evidence and say "that has to be wrong in order for this other theory to remain viable." And then we'd have to go change our climate models. The K-T event would need to look very different. We had an entire continent undergoing extreme volcanism AND miles away a large meteoric impact ... and now we need to lower the gravity too? What does this do to the Permian extinction with its even lower gravity? Sorry... it's like coming up to a sheer-faced cliff and saying "I have a notion that it might be thin as paper" while beside you someone's extracting a core samples doing comparative analysis.

Edited February 26, 2008 by gwangivalley

February 26, 2008

Sorry it took so long to reply, I have had an ongoing family emergency.

I appreciate you responding and I hope things work out OK vis-à-vis the family.

Concede? No, I actually feel pretty good about what I said.

Well.. I have a particular bent about this issue and you come up highly enough in Google that I really felt compelled to come have a chat. In case you're wondering why I've singled you out.

The “false premise” that dinosaurs were too heavy to support their weight was believed by generations of educated men who dedicated their lives to studying dinosaurs. I mention it because -- yes -- it supports my arguments, which I concede are far less humble than my unfinished biology degree.
Modern researchers ARE continually stacking new evidence that:

> Dinosaurs were NOT swamp animals who relied on the neutral buoyancy of water for support of their body weight. They occupied the role of land animals.

> Dinosaurs were highly active.

Well, we can agree on the above just fine.

Unless, of course, you're saying you intend to cling to that 'too heavy' belief to insulate your hypothesis despite the evidence you admit has been accumulated to the contrary.

It is still a false premise (you state as much in those last two lines).

Scientists are not looking for, or continually discovering new evidence that dinosaurs lived in 1.00G. The question of gravitational definition is mudded/clouded by the suggestion that it is a reactionary idea, coupled with those old notions that were blown out of the swamp water by Bakker and others -- and therefore cannot be dignified by any consideration in the scientific community.

I... cannot agree with your first statement. Within the framework of science one builds upon 'best evidence'. One does not have the luxury of working in a vacuum and then filling in around ones hypothesis, one must acknowledge, include and account for the evidences which have come before you. And, at the same time, one must push the boundaries to make sure the walls of some accepted notion do not cave in easily. There is an accepted model of Earth gravity. It is tested every day in any number of disciplines. It is part of our larger model of natural history. Scientists are finding evidence about dinosaurs and early Earth history which do not challenge that model nor suggest problems with it (again further substantiating it).

The 'question of lower gravity' has not shown itself to have merit. There's no conspiracy to ignore the idea, but there's no impetus to favour it. It is no longer considered because the evidence is to the contrary. You really would be asking that large chunks of good science be tossed aside just to reconsider the idea. And without some compelling evidence to defend such a pleading... why would anyone join the cause? It's like asking someone to abandon germ theory, setting aside all the evidence showing it to be true, because you really think there might be something to the miasmatic theory. No one's likely to jump on the bandwagon.

What I will concede is that IF my hypothesis turned out to be correct, it would be a most confounding thing that a biologist WITH a degree did not think of it instead of me. But, that sort of thinking didn't stop Gregory Mendel from discovering genes and it won't shut me up either.

I think you'd be surprised how little your pedigree matters when you've made a profound finding. A bust of Nicola Tesla, a man whose bouts with education were troubled, brief and unfinished, sits in the library of Harvard University's physics department. Here is a man revered in a institute of higher learning so much that he is the only person whose face graces that library, yet he never finished a degree or held a doctoral title.

I hope you don't think I'm trying to shut you up. Neal Adams, yes. He needs to shut up because he's crazy. You, you seem like someone genuinely passionate about discovery. But, I feel, you're missing some pieces of this puzzle which has caught you up so eagerly. You've gone down a garden path that's overgrown for a reason. And you may be leading others down it precisely because you are a bright mind set on a spark (instead of a crazy little egomaniac or a delusional). That is what concerns me.

Yes, I have said that the largest animal that may evolve in any given gravity cannot be as large as the largest that may evolve in lesser gravity, for the same simple reason that a building or a tree could not be as large.
What I'm proposing is that within any geologic period that is puctuated by an increase in surface gravity, animals will continue to evolve larger and larger right up until the increase. Then, it is the largest animals which will suffer the worst from the increase. The largest sauropods, for instance (which died out at the end of the Jurassic) were succeeded by the cretaceous alamosaurs whose camarasaur-like physiology appeared to be a compromise between the brachiosaur design for sheer height, and the diplodocus family's features which allowed it to attain maximum feeding height by rearing back on its tail in a tripod stance.

That is not to set dinosaurs as a benchmark of maximum size to which no animal can ever evolve to be as large in 1.00 G. But, such an accomplishment would probably have to take place over MORE millions of years than before, require a more advanced genetic "state of the art," and is less likely to happen at all than in the mesozoic.

You do love your Bakker. I'm half-tempted to send you some new books. _grin_ Perhaps you'd be more of a John Hutchinson man, if we put Bakker on the table for a while. A lot has happened in the 20 years since Bakker's book. But, by the way, in that time it's still argued whether or not Diplodocus stood on its hind legs. And, again, why this push towards gigantism? You're attempting to reinvent Foster and Case and 'generations of educated men' whose research has withstood scrutiny. There are many factors which influence organism size and chief among them is the amount of energy an organism can take in for a given period. This is why your crocodiles don't grow into monsters. They're quite in balance with their place in the natural world. And a hyperoxic atmosphere can increase gigantism and did so in ages including the Paleozoic and Carboniferous (until the hypoxic crash of the Permian put a stop to it). (see Robert Dudley - The Journal of Experimental Biology 201. See also Kasier, Quinlan, et al. - No giants today...)

But... I need to understand something here. Are you saying that the gravitational increases were punctuated and not gradual/sloped? That the increases came in fits and spurts? (and do you have relative percentages of decrease in gravity? i.e. - at x million years gravity was x% of 1G.)

Also... Yes. The trees. Have you considered the trees, by the way? How they would behave in the Cambrian? Mesozoic? Permian? Carboniferus? and on as gravity supposedly increased? Just curious if you've thought about this.

The fact that pterosaurs' "very livelihood was tied to gravity" is to say that they were HIGHLY SPECIALIZED to operate against gravity. Now here's where I would say, ADAPTED and SPECIALIZED are not exactly like terms. Birds are very well adapted against the force of gravity. So well adapted, in fact, that their flying mechanism folds onto their back and is tucked away so that the bird can temporarily function as a land animal. A pterosaur or bat on the other hand is so specialized against gravity -- its anatomy completely given over to the flight mechanism already -- that an increase in gravity would be more likely to ground it for good. And in the case of the pterosaurs, I say it did. Like a heavily-sponsored race car that can't fit one more decal on its frame, there was no room for further adaptation; the pterosaurs' flight technology was mature.

I think you're quibbling with the whole 'adapted versus specialized'. Both animals flew/fly and walk/walked. See:

Posture, Locomotion, and Paleoecology of Pterosaurs - Sankar Chatterjee and R.J. Templin - Geological Society of America (ISBN 0-8137-2376-0)

In brief: Pterosaurs flew pretty well in the traditional sense (all calculations and derivations weighted in a 1G world), except for the very largest which still appear to have been rather good gliders,. They could also morph their wing shape.

Adaptation and specialization.

I appreciate the more-specific argument that a lower-G atmosphere would be less dense. As you said, the atmosphere was more oxygen-rich. However, Oxygen is heavier than the other abundant gas in the atmosphere: nitrogen. I conceded earlier that the change in ratios itself does not imply gravitational definition because the gases do not achieve escape velocity; only hydrogen in the outermost layer does that. But, the effect of reduced air pressure would be offset by the change in ratios.
Have paleoentomologists determined that the large size of ancient insects, with their greater ratio of body volume to body surface area, with their trachael respiratory tubes that reach every cell of their bodies like capillaries, allowing for their slower, open circulatory systems to forego the role of gas transport... that their larger size was only possible due to a denser atmosphere? I hadn't heard that, so by all means provide a or periodical reference for me to check out.

Density is a function of pressure and volume. Lower gravity, lower pressure, less density. Bug's gotta take in more air to get enough oxygen out of it. Bug's also got to work harder to fly.

You know, you are free to personally consider my ideas however you like. I do not log onto this site with the intent to confuse anybody. I will read further into the relevant areas of science as my work schedule allows, and as my family emergency is hopefully resolved in the next couple of weeks. But as a working man with big stuff going on, I think I'm doing all right as far as maintaining an intelligent discussion here. I may not get the chance to reply quickly, but I'll reply when I can. And like other things in my life, I believe what I'm doing and saying, and not asking others to consider something that I believe in my heart is bogus. In other words, I'm not blowing smoke like Kevin Tredeau (sp?) just to make a name for myself.

Again, I hope things at home work out well and soon. And I would like to reiterate that I don't consider you a quack. I think there are gaps in your knowledge that are allowing you to fall into holes which don't have to be.

My point of view is investigative, but investigation requires time that I don't have right this minute. Until I can, I will argue what I find to be arguable. The overall assumption that any groundbreaking new idea can only come from someone with a big degree and a government paycheck... I don't consider that valid.

Recall what I said about Tesla. I am not making that argument. But, I will argue for the superiority of data. And those with access to the resources to investigate will necessarily produce superior data. Especially in the modern world we live in where that data is then passed on to others to peer at and poke and rip apart if they can, or acknowledge as strong when they cannot. And much of that same data is available to you, for you to weigh and consider. (hehe But please, put the Bakker down for now.) I would urge you to look into the work of Chatterjee and also Hutchinson to fill in the potholes.

Ella

PS - No, I'm not single. Sorry. And as for my blog, I do indeed host it using Wordpress software (but one could also use blogger or the like instead of hosting it yourself - I just do so because it works best for me). I don't actively promote the site, per se, but it gets enough traffic to keep me doing it (I blog elsewhere as well, but this site allows me freedoms I don't otherwise have. I stopped blogging at another site once I decided to do gwangivalley.com, and as you can see it hasn't been there very long.)

Edited February 26, 2008 by gwangivalley

February 26, 2008

Hello, Fabrosaur.
I have to say that your response 1. is a bit troubling as there's both no evidence to suggest such a thing and no reason to assume this was the case evolutionarily. You're asking to 'solve' a problem that doesn't exist. Selective pressures to grow large surely existed, because the animal grew larger, but there's no evidence to support the notion that gravity increase was among those pressures. Queztlcoatlus' wing area to mass ratio is much less favourable than its smaller, earlier brethren such as Thalassodromeus or Tupuxuara (A good chart to do the math from can be found in - Humphries S, Bonser RHC, Witton MP, Martill DM (2007) Did Pterosaurs Feed by Skimming? Physical Modelling and Anatomical Evaluation of an Unusual Feeding Method. PLoS Biol 5(8): e204 doi:10.1371/journal.pbio.0050204).

This sort of falls smack into point 2. Circumstantial evidence, of which I see very little, cannot hope to contend with physical, experimental and observational evidence in a fair fight.

Unless this circumstantial evidence is packing a knife. It had also best bring a pickaxe to break up and hide the sedimentary evidence which flows evenly and as expected in the geological record and never indicates this gravity difference.

And, I have to be frank, it's not up to me to 'falsify' lower paleogravity, it's up to you lot to falsify the evidence to the contrary as the case for this alternative theory is light enough to take flight in even the thin atmosphere we keep coming back to. Yet evidence against it is rather... weighty (no gravity pun intended).

The preponderance is upon you.

Extraordinary claims require extraordinary evidence.

When one claims that gravity change may have played a role in dinosaur extinction, one must being by answering the challenge of the scientific record which does not indicate anything of the sort took place.

And, forgive me... but what _is_ you boys' fascination with gigantism? LOL

Sure, there were giant things then and there are giant things now. There seems to be some notion that gigantism is an evolutionary goal. Every niche is not a large hole. But if one takes a 2 foot wingspan dragonfly-like insect and sticks it into our atmosphere, it will not survive. That's a point of a very fine nature. (as Dinotheorist rightly asks me to cite more in his response, I'm doing so here as well. See this story and associated papers which show recent studies bearing this out: http://www.sciencedaily.com/releases/2006/...61012093716.htm ). We know with a great degree of certainty the atmospheric makeup in question and there was definitely a higher oxygen concentration that allowed these insect to live (without the aid of respirators or oxygen tents). We also know how gases of a planetary body behave under different gravitational influences.

Lowering the gravity for the Mesozoic or the Cambrian would have a marked change on the Earth model and the inhabitants as observed. It would require us to set aside good evidence and say "that has to be wrong in order for this other theory to remain viable." And then we'd have to go change our climate models. The K-T event would need to look very different. We had an entire continent undergoing extreme volcanism AND miles away a large meteoric impact ... and now we need to lower the gravity too? What does this do to the Permian extinction with its even lower gravity? Sorry... it's like coming up to a sheer-faced cliff and saying "I have a notion that it might be thin as paper" while beside you someone's extracting a core samples doing comparative analysis.

Response to guangivalley

When the impact theory of extinction was introduced there were many who opposed it. Many of those people had their careers damaged, funding for their research grants dried up and they were denigrated because they did not jump on the impact bandwagon. Those that have written books and articles supporting the impact theory of extinction have a vested interest in not having an alternate take hold and displace the one which they have spent so much time and effort supporting. It’s a threat to them. I’m not saying that you are part of that group nor will I ask you if you have a vested interest in not seeing an alternate (like the “grav-chg”) theory challenge the orthodox theories of extinction. However, I do find it strange that you would create a website, post a negative comments about a fledgling theory, post the message “Comments are Closed” before there are any comments. Strange.......very strange.

1. Your initial post mentioned the increasing size of the pterosaurs as evidence against the grav-chg explanation of gigantism. I countered that it is evidence for grav-chg. You agreed that there were “selective pressures to grow larger surely existed” for the pterosaurs but you didn’t hazard a guess as to what those pressures were.

What is your opinion about why the pterosaurs increased in size toward the end of the Mesozoic?

You cite an obscure publication about pterosaurs to support your position that Queztlcoatlus’ wing- area to mass ratio is much less favorable than its earlier brethren. Again, you fail to be specific.

Please provide specific information to support that pterosaur wing area/mass claim.

2. Your claim that “if one takes a 2 foot wingspan dragonfly-like insect and sticks it into our atmosphere, it will not survive.” You are right! However, it’s not because of oxygen levels; it’s due to current gravity. Elevated oxygen levels might increase the metabolic efficiency but that’s about all. That dragonfly would still have to flap its wings in the same manner that today’s dragonflies do.......fast.....very fast. The energy expended, the heat generated would lead to a quick extermination.

I don’t subscribe to the oxygen level/gigantism nexus. If it had any validity, then:

A. Elevated oxygen levels would have to have been in effect continuously throughout every period in which gigantism was noted including the Carboniferous, late Triassic, Jurassic and Cretaceous.

B. Elevated oxygen levels would reduce the growth of flora. Gigantism in Mesozoic flora existed.

C. As I noted in a previous post, marine gigantism is well documented. At oceans’ depths, there were anoxic conditions. Giant inoceramids (clams) reached six feet in diameter and they appeared to have thrived in low oxygen conditions.

Yes, Extraordinary claims require extraordinary evidence.

Grav-chg is still alive!

Edited February 26, 2008 by Fabrosaur

February 27, 2008

Response to guangivalley
When the impact theory of extinction was introduced there were many who opposed it. Many of those people had their careers damaged, funding for their research grants dried up and they were denigrated because they did not jump on the impact bandwagon. Those that have written books and articles supporting the impact theory of extinction have a vested interest in not having an alternate take hold and displace the one which they have spent so much time and effort supporting. It’s a threat to them. I’m not saying that you are part of that group nor will I ask you if you have a vested interest in not seeing an alternate (like the “grav-chg”) theory challenge the orthodox theories of extinction. However, I do find it strange that you would create a website, post a negative comments about a fledgling theory, post the message “Comments are Closed” before there are any comments. Strange.......very strange.

If by 'strange', you mean "that's what the blogging software adds at the end of each post if you do not specifically turn comments on", then yes.

If by 'strange' you mean 'suspicious and/or nefarious', then hop on your black helicopter and ride, man.

You're arguing that the vested interest hinders change by pointing out a previous change which toppled a vested interest? You're playing the 'the man' card? Seriously. Don't go all '9/11 Truth' on me

Challenges... You mean like accepting warm-bloodedness? Feathers? That T. rex is not a carnosaur after all and needs to be moved to the Coelurosaurs?

Right now there are string theorists holding their breathe for when the new LHC comes on line and could, potentially, basically end their careers if evidence comes out out that negates their theories. And many of them are actively involved in helping this happen.

That balloon of an idea you hold about how science really operates is leaking like a sieve. You should let it go before is bursts all over you.

1. Your initial post mentioned the increasing size of the pterosaurs as evidence against the grav-chg explanation of gigantism. I countered that it is evidence for grav-chg. You agreed that there were “selective pressures to grow larger surely existed” for the pterosaurs but you didn’t hazard a guess as to what those pressures were.

Yes. Because I assumed you had a modicum of understanding of how evolution works.

What is your opinion about why the pterosaurs increased in size toward the end of the Mesozoic?

Simple. It was in their interest to do so. And not all pterosaurs of the Cretaceous were giants. That's how it works in the everyday normal worlds where one doesn't have to adjust gravity to see species grow or shrink. It's no big mystery -- animals grow and/or shrink over time if its in their interest to do so. And the number one reason is generally food supply. An increasing gravity has not been found to be a plausible factor.

You cite an obscure publication about pterosaurs to support your position that Queztlcoatlus’ wing- area to mass ratio is much less favorable than its earlier brethren. Again, you fail to be specific.
Please provide specific information to support that pterosaur wing area/mass claim.

Oh for frack's sake. Is this the problem? You're unable to do even the simple parts of investigation? This _obscure_ publication from a well-respected, highly peer-reviewed researcher who's done more hands on work with Mesozoic vertebrate evolution and biological systematics than nearly anyone alive... a man, I might add who you should like because he's proposed more than a couple of 'non-bandwagon-jumping-on' ideas which go against some accepted notions. For the love of bob, I cited it because it has a very simple chart showing wing area and mass for several pterosaurs from which one can easily do simple division on and come up with a ratio. It's on Google books.

Quetzalcoatlus. Max A to M ratio = 0.11 if allowing the _most favourable_ mass estimate. Pteranodon easily gets a 0.12. Thalassodromeus whips them both with a 0.15 to 0.16. Tupuxuara may have scored as high as 0.22.

And I'm not doing the math for you next time. You didn't do any for me.

2. Your claim that “if one takes a 2 foot wingspan dragonfly-like insect and sticks it into our atmosphere, it will not survive.” You are right! However, it’s not because of oxygen levels; it’s due to current gravity. Elevated oxygen levels might increase the metabolic efficiency but that’s about all. That dragonfly would still have to flap its wings in the same manner that today’s dragonflies do.......fast.....very fast. The energy expended, the heat generated would lead to a quick extermination.

Well then. We know one more thing. You do not understand insect respiration.

It is exactly because of oxygen levels. It is _entirely_ about oxygen levels. Your denial of this fact makes it no less true.

I don’t subscribe to the oxygen level/gigantism nexus.

So we see.

If it had any validity, then:
A. Elevated oxygen levels would have to have been in effect continuously throughout every period in which gigantism was noted including the Carboniferous, late Triassic, Jurassic and Cretaceous.

B. Elevated oxygen levels would reduce the growth of flora. Gigantism in Mesozoic flora existed.

C. As I noted in a previous post, marine gigantism is well documented. At oceans’ depths, there were anoxic conditions. Giant inoceramids (clams) reached six feet in diameter and they appeared to have thrived in low oxygen conditions.

A. No. You're stripping out individual parts of an equation -- applying new rules. You're making special size increase a black and white issue. You simply cannot have these sorts of discussions with these short equations, removing other factors to focus on only two will not give you truthful results.

B. Dude. We know... for a fact... that oxygen levels were higher. If you wish to continue to debate that, then please move your black helicopter or UFO over with the Bigfoot crowd so that I can properly label and ignore you.

C. And as I now note... so? I'm quite obviously not arguing against the occurrence of gigantism nor trying to oppress the rights to exist of giants anywhere. I noted that you guys seem to have a raging woody for it as though it were a natural goal on the evolutionary soccer field and the prime mover for it is gravity. I then took a moment to reiterate about the giant bugs and elevated oxygen levels which solidify our model of the world and do not ever once call for lower gravity nor would said lower gravity fit said model.

Yes, Extraordinary claims require extraordinary evidence.
Grav-chg is still alive!

It lives in a giant room filled with no evidence extraordinary or otherwise. A giant room in someone's imagination.

(Edited for typos: burst -> bursts, are -> area)

Edited February 27, 2008 by gwangivalley

February 27, 2008

PS - "...post a negative comments about a fledgling theory..."

Gasp! I'm so evil! If you think my comments on my blog were harsh, then you should see how it happens in the research world for published theories/hypotheses. You paint a picture of ivory towers where the status quo must not be disturbed when, in fact, it's more like a brawl. Peer review is about poking, prodding and tearing at something. If it comes apart, the author didn't do their homework and needs to go back to the lab. If it doesn't fall apart, it gains a level of respect (and then someone else promptly steps in to poke, prod and tear at it from another angle).

That's how science operates.

February 27, 2008

PS - "...post a negative comments about a fledgling theory..."
Gasp! I'm so evil! If you think my comments on my blog were harsh, then you should see how it happens in the research world for published theories/hypotheses. You paint a picture of ivory towers where the status quo must not be disturbed when, in fact, it's more like a brawl. Peer review is about poking, prodding and tearing at something. If it comes apart, the author didn't do their homework and needs to go back to the lab. If it doesn't fall apart, it gains a level of respect (and then someone else promptly steps in to poke, prod and tear at it from another angle).

That's how science operates.

Gwangivalley shows his limitations in scientific knowledge. I asked him to speculate on the enormous increase in the size of pterosaurs, such as Quetzalcoatlus, toward the end of the Mesozoic. He responds:

"Food supply"

Does he try to explain what "food supply means"? Of course not.

Does he try to explain why other animals weren't experiencing similar growth changes? Of course not.

I suppose his next post will claim that they were taking steroids.

In response to my request for specific info on his claim of higher wing-area to mass of smaller pterosaurs, he gets huffy and starts throwing out "fracks", "love of Bob" and "raging woody." Dude, your on the wrong forum for that stuff. I think that earthquake over in the U.K. must have rattled his brain.

He makes the case for a Carboniferous dragonfly's gigantism based on higher oxygen levels. I point out several bits of info that indicate otherwise. He gets huffy again and instead of providing scientific support, he starts mentioning UFOs, Bigfoot and black helicopters. He must be one of those sci-fi movie fans. At first I thought he might have been the author of an extinction theory and was trying to defend his turf. His posts have proven that is very unlikely.

I don't know if I'm wasting my time with him, but maybe there is a modicum of hope.

I did find the table he mentioned in the previous post. The information there is erroneous. The wingspan for Quetzalcoatlus is given as 10.39m which is less than the largest estimates of 12-14 meters known. The weight is, unlike the wingspan, given as a range of 45.8 to 200kg. That's the first indication of incompetence by the articles authors. They provide a wing area of 5.12 m^2. Was this a guess? Did they assume that the wing was the shape of a right triangle? This area is much too small. The document must be discarded. It is, as they say across the pond, Codswallup!

February 27, 2008

Excuse me if somebody else has said this in a post which I haven't read (I'm too lazy, srry ),

but around 65 million years ago the oxygen levels in the air were dropping. The big dinosaurs were dying slowly and the meteorite finished them completely. The dino's couldn't handle the lower oxygen levels because the were not able to breathe like we do. Like all other reptiles and birds for that matter, they didn't have a breastbone and very primitieve lungs, which made it impossible for them to breathe in large quantities of air like we can or, for that matter, a giraffe. That's one of the reasons we don't have any big lizards anymore.

Peace out,

ps don't kill me if I'm wrong in anyway , it's been a while since I last mentioned this theory. But the decreasing oxygen levels were found in the ground and fossils of big dino's started to increase before the meteorite struck.

February 28, 2008

Dear Fabrosaur,

You don't understand how evolution works, apparently don't understand what's meant by selective pressures (I'll give you a hint - recall when I mentioned food?), don't understand insect respiration and lastly can't do enough of your own research to even sort out that I'm not a he.

I don't have the time or desire to waste on you. Dinotheorist, I'm still happy to discuss things with you, if you wish. But Fabrosaur is ignorant of many things, casres not that he is and appears to be a true believer. I keep forgetting that this is a site populated by lots of people like him. Perhaps it was a bad ida to come here at all.

Ella

PS - For anyone reading who cares, the Lawson Quetzalcoatlus find's estimated size has been revised down based on our improved understanding of the anatomy of the beasts based on evidence from more complete remains.

February 28, 2008

simple, they were reptiles. if you check most of the reptiles out they don't need to eat as often as animals today

February 28, 2008

For anyone interested in the largest pterosaurs, look at:

http://www.blackwell-synergy.com/doi/pdf/1...51.2007.00596.x

The estimate for the weight of Quetzalcoatlus is estimated to be 70-85kg rather than the 70-250kg estimates given elsewhere.

The reason for their extinction isn't the real one.....you know what that is.....but the info on this site is up-to-date.

*****I noticed that when I tried to view this site again, Blackwell blocked free access. It's only a 6 page article.....it's not worth paying anything for it.***********

Edited February 29, 2008 by Fabrosaur

March 2, 2008

Dinotheorist, I'm still happy to discuss things with you, if you wish. But Fabrosaur is ignorant of many things, casres not that he is and appears to be a true believer. I keep forgetting that this is a site populated by lots of people like him. Perhaps it was a bad ida to come here at all.

I like you gwangi, please don’t go.

Regarding my family emergency, My sister and I seem to have made it through another weekend of fixing up her house despite the actions of a bunch of back'ards Billy-Bob bozos whose idea of a well-run sheriff's department is somewhere just this side of Commie Zimbabwe. I must strongly urge that anyone wishing to move to the State of Florida put the names of your would-be county leaders to a search engine or two before you make any decisions. Enough of that...

Modern researchers ARE continually stacking new evidence that:
> Dinosaurs were NOT swamp animals who relied on the neutral buoyancy of water for support of their body weight. They occupied the role of land animals.

> Dinosaurs were highly active.

Well, we can agree on the above just fine.
Unless, of course, you're saying you intend to cling to that 'too heavy' belief to insulate your hypothesis despite the evidence you admit has been accumulated to the contrary.

It is still a false premise (you state as much in those last two lines).

Scientists have accumulated a lot of evidence all right, but evidence of what? What I am trying to say is that it appears to me that scientists have missed something in the evidence that has been collected. Like the way they missed the fact that dinosaurs were highly active land animals. Like microbiologists missed the most basic aspect of HIV infection for an entire decade. Like astronomers before Copernicus and Galileo, biologists before Darwin and Mendel.

Here's another way saying it... IF we were able to examine the history of evolution on a planet known to have less surface gravity than the Earth we live on today, THEN we would probably see larger land animals. We would see larger land animals for the same reason that we see large whales in the neutral buoyancy of the ocean. Some class of animal would evolve to be larger for the same reason that any animal might be pressured to become larger: competition within a species, resistance against a predatory species, more effective use of food sources (such as a TREETOP FEEDING BRACHIOSAUR). IF gravity were lower, THEN it too would be... not really a pressure to grow larger, but rather an allowance factor. The evolutionary development of that larger body is no manifest destiny; it must be invented through the same hit-and-miss selective process that it always is, and that invention will be in stages over a large stretch of time. It will progress over more time in heavier gravity, less time in lighter gravity. It will progress in less time in lighter gravity (apart from other factors) because it can.

Outrageous speculation? The branches of a southern live oak can spread out horizontally to feed on the sunlight, because the lack of snowfall where it grows is an allowance factor. Lower gravity would allow a northern species of tree to sprawl its branches and be able to support the weight of snow and ice in the winter. The evolution of wood that is lighter and stronger would be another solution, but seems to be of rarified attainability.

Exobiology may be a speculative science, but by golly it sure could save you the money of locating and traveling to another bioshere to answer a simple question. I view this type of speculation as perfectly all right. Paleontology is like exobiology, because you're studying an ecosystem that is almost alien. We don't have the real live thing right in front of us any more, so we have to think about everything... even things that we think about as always being the same, like sunlight and gravity. And when I consider gravity, we see that dinosaurs have what appear to be glaringly apparent lower-gravity characteristics.

It doesn't stop with the larger size of the dinos. I have stated perfectly good reasons for why birds and crocodilians would be the logical survivors of a surface gravity increase event, and the fact that they have not produced new dinosaur-like forms is perfectly relevant to this discussion. They are the most closely related animals to dinosaurs. They even possess the dinosaur digestive mechanism, a stone-lined gizzard. In all the Cenozoic, the opportunity to encroach back into the role of major land animal has been spread out before them like a picnic. You say that, "birds and crocodiles are doing fine in the roles that they're in" and therefore, "they don't need to become monsters." But that's like saying that if you keep a meatloaf in your refrigerator that is richly festooned with different species of bacteria, it is less likely that some of those bacteria will find a way to spread to your cheese -- because they're doing fine on your meatloaf. It's not logical, Gwangi.

Scientists are not looking for, or continually discovering new evidence that dinosaurs lived in 1.00G. The question of gravitational definition is mudded/clouded by the suggestion that it is a reactionary idea, coupled with those old notions that were blown out of the swamp water by Bakker and others -- and therefore cannot be dignified by any consideration in the scientific community.

I... cannot agree with your first statement. Within the framework of science one builds upon 'best evidence'. One does not have the luxury of working in a vacuum and then filling in around ones hypothesis, one must acknowledge, include and account for the evidences which have come before you. And, at the same time, one must push the boundaries to make sure the walls of some accepted notion do not cave in easily. There is an accepted model of Earth gravity. It is tested every day in any number of disciplines. It is part of our larger model of natural history. Scientists are finding evidence about dinosaurs and early Earth history which do not challenge that model nor suggest problems with it (again further substantiating it).
The 'question of lower gravity' has not shown itself to have merit. There's no conspiracy to ignore the idea, but there's no impetus to favour it. It is no longer considered because the evidence is to the contrary. You really would be asking that large chunks of good science be tossed aside just to reconsider the idea. And without some compelling evidence to defend such a pleading... why would anyone join the cause? It's like asking someone to abandon germ theory, setting aside all the evidence showing it to be true, because you really think there might be something to the miasmatic theory. No one's likely to jump on the bandwagon.

In our time, we have watched mainstream paleontology go from what those children's books used to say about slow, swamp-dwelling sauropods to the post-Bakker era. Yeah, I like Bakker and would like to read more books like Heresies by different authors. I have noted your recommendations and added them to my reading list. But, do you know what I would have expected to read in Dinosaur Heresies, or some similar book, in all the discussion and foment about how heavy the dinosaurs possibly could have been? That is, if there was no merit to paleogravity? Consider if you will the following mad-libbed paragraph:

"Did dinosaurs really weigh as much as their bone diameters and muscle attachment sites suggest they did, somehow made of stronger stuff like a theoretical, sprawling live oak with such strong branches that it can grow where it snows? Or, were they leaner, knobbier-kneed giants that were light in every way EXCEPT for their bones? If it were an easy question to answer, there probably wouldn't be so many articles in science periodicals arguing back and forth. But one thing we can all be sure of is that a lower-gravity environment cannot possibly be the answer, because "so-and-so" did "that study" that demonstrated that rocks which would surely have formed differently in their crystal structure did not form differently. Then there's that study by "that other geologist" that volcanically ejected rocks, whose structures indicate their masses and pressures at ejection (and points of origin are known), traveled no farther in their trajectories than volcanically ejected rocks do today. It was proved! And as if that wasn't enough, there's the astronomer who showed that the difference in tidal friction on the moon would have produced an entirely different result in the lunar orbit than what we now see. Sedimentary Mesozoic rocks surely formed under one G because What'shername built a centrifuge to grow sedimentary rocks in simulated heavier gravity, producing results that made theoretical <1g -formed sedimentary rock structures mathematically predictable. And oh yeah, Mesozoic sedimentary rocks only match the 1G result. So, the question is as settled as it ever was."

The above paragraph, or anything else like it, does not seem to exist anywhere. That concerns me.

Sure there have been studies, but not none specifically purposed to check the surface gravity of eras past. I don't even know -- poor me -- what studies inadvertently prove a 1G Mesozoic environment when you take a purposed look at their data which may have been collected to prove something else. It is well enough to say "That's because there's no need... the very idea of <1G Mesozoic no benefit to their career."

Fine then. My career is selling flooring at the Home Depot, so I'll propose it. And until I hear a lot more specific reasons why Mesozoic <1g is not possible, I must continue to banter.

I say nobody checked, gwangi.

I think you'd be surprised how little your pedigree matters when you've made a profound finding. A bust of Nicola Tesla, a man whose bouts with education were troubled, brief and unfinished, sits in the library of Harvard University's physics department. Here is a man revered in a institute of higher learning so much that he is the only person whose face graces that library, yet he never finished a degree or held a doctoral title.
I hope you don't think I'm trying to shut you up. Neal Adams, yes. He needs to shut up because he's crazy. You, you seem like someone genuinely passionate about discovery. But, I feel, you're missing some pieces of this puzzle which has caught you up so eagerly. You've gone down a garden path that's overgrown for a reason. And you may be leading others down it precisely because you are a bright mind set on a spark (instead of a crazy little egomaniac or a delusional). That is what concerns me.

At least Tesla was able to build devices which proved what he said. I feel as if I know how he felt in the times after he was able to explain what his mind saw, and before the money was put up to build those devices which (after all) had incalculable future industrial applications.

Even if I'm wrong, I can fulfill a legitimate purpose in the field of paleontology by making career paleontologists prove what they say. Someone here said, "if the Earth shrank, then where did all the ocean water go? It should have flooded the Earth instead of receded." That is the single best argument against the paleogravity hypothesis that I've heard to date. The only defense I can think of is that the increase in surface gravity must be due to something other than Earth contraction, or that changes in the shape of the ocean floor caused chasms to form. What else have you got? I'm not as high up in Google as Britney Spears, but like she says, Gimme gimme (more).

... I need to understand something here. Are you saying that the gravitational increases were punctuated and not gradual/sloped? That the increases came in fits and spurts? (and do you have relative percentages of decrease in gravity? i.e. - at x million years gravity was x% of 1G.)
Also... Yes. The trees. Have you considered the trees, by the way? How they would behave in the Cambrian? Mesozoic? Permian? Carboniferus? and on as gravity supposedly increased? Just curious if you've thought about this.

Yes and yes. Punctuated increases are the only way it could have happened, and a steady increase would be as impossible as you say. I would propose that a single-digit percent increase would be enough to cramp the style of a modern giraffe, and have a sufficiently negative effect on its reproductive success to push it to extinction -- because that's all that's necessary to cause extinction; a negative impact on reproductive success against competing animals. Giraffes drop their newborns several feet to the ground at birth, and brachiosaurs had those giant eggs. Whatever increase it would take to hurt a giraffe, less so a brachiosaur.

Also, the giant sequoias and redwoods of California are Jurassic trees that are quite rarified today. I notice that all Jurassic trees such as pines seem not to challenge gravity horizontally these days, and so ironically get the job of growing in snowy climates very different from their evolutionary origin.

I once dug up an “interrupted fern” to transplant it, which someone told me was a species dating very far back in the fossil record. I noticed that it collapsed once it no longer had soil around its base to support it.

The fact that pterosaurs' "very livelihood was tied to gravity" is to say that they were HIGHLY SPECIALIZED to operate against gravity. Now here's where I would say, ADAPTED and SPECIALIZED are not exactly like terms. Birds are very well adapted against the force of gravity. So well adapted, in fact, that their flying mechanism folds onto their back and is tucked away so that the bird can temporarily function as a land animal. A pterosaur or bat on the other hand is so specialized against gravity -- its anatomy completely given over to the flight mechanism already -- that an increase in gravity would be more likely to ground it for good. And in the case of the pterosaurs, I say it did. Like a heavily-sponsored race car that can't fit one more decal on its frame, there was no room for further adaptation; the pterosaurs' flight technology was mature.

I think you're quibbling with the whole 'adapted versus specialized'. Both animals flew/fly and walk/walked. See:
Posture, Locomotion, and Paleoecology of Pterosaurs - Sankar Chatterjee and R.J. Templin - Geological Society of America (ISBN 0-8137-2376-0)

In brief: Pterosaurs flew pretty well in the traditional sense (all calculations and derivations weighted in a 1G world), except for the very largest which still appear to have been rather good gliders,. They could also morph their wing shape.

Adaptation and specialization.

There's no way the pterosaurs were as good on the ground as birds, just like bats aren't as good. Therefore it is they, and not birds, that would have been more affected by the event I propose.

Density is a function of pressure and volume. Lower gravity, lower pressure, less density. Bug's gotta take in more air to get enough oxygen out of it. Bug's also got to work harder to fly.

A larger bug has to take in more air? Sure, but I don't see how larger size impedes that ability at a given air pressure. If the lower skin-surface area-to-body-volume was the reason, by virtue of gas exchange occurring on their skin surface, then I could see it. But terrestrial arthropods have an internal mechanism that does it, though different than mammal lungs. If size and oxygen percentage mattered, then I would expect the title of "world's largest terrestrial arthropod species" to belong hands-down to a long-bodied scorpion or dragonfly, and for the bird spider and goliath beetle to lag far behind. But, it's not so. Further, I have always heard that it is the riddance of carbon dioxide and not the oxygen content of an atmosphere that is more important to air-breathers. A suffocated organism does not die from a lack of oxygen in its air supply, but from the buildup of carbon dioxide which is far more soluble. Don't feel bad if you missed this, because NASA burned up three astronauts on the launch pad not realizing that an all-oxygen atmosphere was useless anyway. And one more thing: I agree and acknowledge that the atmosphere was more oxygen-rich in the Mesozoic, because whatever the turnover mechanisms are for oxygen and nitrogen in the atmosphere, their ratios at Earth's surface are to some extent gravitationally defined, right? Higher gravity brings more of the lighter gas -- nitrogen -- closer to the Earth's surface, so the richer-O2 Mesozoic is a point for me, as I see it.

Again, I hope things at home work out well and soon. And I would like to reiterate that I don't consider you a quack. I think there are gaps in your knowledge that are allowing you to fall into holes which don't have to be.

But I tell you, there is something cool down here.

I would urge you to look into the work of Chatterjee and also Hutchinson to fill in the potholes.
Ella

Thank you Ella, and all who have offered suggestions for reading. My current list is:

Earth: An Intimate History by Richard Fortey

John Hutchinson

Chatterjee

Robert Dudley - The Journal of Experimental Biology 201.

Kasier, Quinlan, et al. - No giants today.

gravity and dinosaurs

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