Gravity and dinosaurs

In need of some one that knows more about gravity than i do as the way i understand it and i am probably wrong is that the dinosaurs would be unable to pump blood around there body let alone stand

Any takers

Steve

Originally posted by battl3star
In need of some one that knows more about gravity than i do as the way i understand it and i am probably wrong is that the dinosaurs would be unable to pump blood around there body let alone stand

Any takers

Steve

I'll bite, but only in small portion...I believe you might be confusing this with why spiders and so forth aren't larger (and that deals primarily with oxygen available in the air and their means of respiration, as I understand), as I'm not aware of any claimed differences in gravity between now and the time of the dinosaurs.

Also, we've got (relatively) large land animals today that get along fairly well. Appears physiology will work these things out, although it's questionable if we completely understand the stances of various dinosaurs - which might play in here somewhat.

Take care.

I always wondered about that as well. The sheer mass of these creatures is immense. If you double the height of an elephant you quadruple the mass. The weight supported by the hearts(s) is massive. Even "small" creatures such as insect and molluscs were enormous.

Try this : look at the largest land animal through the ages and they peak around the Triassic period, after that they get smaller and smaller so that an elephant is todays largest land animal.

Go back 100,000 years and mammals across different genera (cats, mammoths, bears, bovine, man-neanderthal!) were all larger. we are supposed to believe that man drove them to extinction. How about increasing gravity (sharp intake of breathe) made them unable to compete with smaller faster competitors!!!

Note how water based creatures don't follow this pattern for obvious reasons.

Just a thought...........

When the dinosaurs were around the earth was more oxygen rich which is why they were so large, there has been tests on insects which are put into an oxygen rich chamber and they grow larger than normal.

The dinosaurs may have been large but so were their muscles and bones which help hold the extra weight.

Its like saying look at a mouse, its tiny but millions of years ago they were huge, how is this possible they were maybe a 100 times bigger...

Cue: lets say an elephant, its far bigger but has bigger muscles and bones to compensate, you really should't think about size and gravity when it comes to muscle and bones that control it.

reply to post by battl3star


Not to mention the fact that so many creatures that we have today were much larger....Heck prehistoric dragonflies had three foot wingspans! Add to that the fact that modern paleontologists still have difficulty explaining how anything as large as some of the pterodactyls ever got airborne. For instance they say the bigger ones could have only gotten airborne by jumping off cliffs like hang-gliders.....which would mean they'd have a horrible time getting back up to the cliff if they accidentally landed on the ground below it! How exactly did they capture food while hang-gliding around? This would seem to me to be an obvious evolutionary disadvantage....yet the evolved that way....

Of course all of this makes sense if the gravity on the planet earth was a tiny bit less. It's a concept I really enjoy thinking about, but it's hard to find a theory that can make it fit. Some versions of the 'expanding earth theory' might work...but I've never heard a really good explanation for how the process might work

Also, the MOST massive of the sauropods were believed to be mostly swamp dwelling or semi-aquatic such as hippos to support most of their weight. Evidence of this is embodies in the Brachiasaur which is a super-massive sauropod and has nostrils on TOP of its head.

Gravity may have also been different because the moon was MUCH closer to the earth perhaps negating some of the pull down toward the ground. Also, the alleged meteoric impact 65 million years ago may have moved the earth further away from the moon, thereby reducing its gravitic influence.

reply to post by bhornbuckle75
It's probably been clearly refuted somewhere I just haven't bothered to find yet, but I loves me some expanding earth theory and it seems to make a good bit of sense as well as account for things like this. Star for you, friend.

Originally posted by dashen
Gravity may have also been different because the moon was MUCH closer to the earth perhaps negating some of the pull down toward the ground. Also, the alleged meteoric impact 65 million years ago may have moved the earth further away from the moon, thereby reducing its gravitic influence.

The earth's mass defines its gravity the moon pulling on it is negligible (apart from the tides), as a creatures size increases so does it organs (apart from the brain)

An elephant has a far larger heart than a mouse for example, because it needs to be to have the pressure to push the blood around such a large animal.

reply to post by bhornbuckle75


Nice vid thanks.But yea it don't fit as where the hell did all that mass come from sure as hell was not meteor or comets

Originally posted by roughycannon


The earth's mass defines its gravity the moon pulling on it is negligible (apart from the tides), as a creatures size increases so does it organs (apart from the brain)
.

Please explain how lifting 342,543,511 cubic miles of water in the oceans of the world many many feet is negligible. Also, imagine the moon was half the distance from earth, that effect would be multiplied.

Also, as whales increased in size, so did their brains. Also squid. perhaps not proportionally though.

Originally posted by battl3star
reply to post by bhornbuckle75

 

Nice vid thanks.But yea it don't fit as where the hell did all that mass come from sure as hell was not meteor or comets

Maybe its not necessarily extra mass, but extra volume.

Originally posted by dashen

Originally posted by roughycannon


The earth's mass defines its gravity the moon pulling on it is negligible (apart from the tides), as a creatures size increases so does it organs (apart from the brain)
.

Please explain how lifting 342,543,511 cubic miles of water in the oceans of the world many many feet is negligible. Also, imagine the moon was half the distance from earth, that effect would be multiplied.

Also, as whales increased in size, so did their brains. Also squid. perhaps not proportionally though.

edit on 26-10-2011 by dashen because: more info

The moon doesn't lift 342,543,511 cubic miles of water, it pulls the surface creating what we call waves, these waves like a domino effect create the sea and tides which we know today.

A whales brain increased in size because of evolution not because of how large it was, a T-rex brain was small compared to how large it was for example.

reply to post by dashen


Think it may be because the moons effect is only temporary as the tide follows the moons orbit so any poor dinosaur left on the other side would die

Not sure to be honest

The moon doesn't lift 342,543,511 cubic miles of water, it pulls the surface creating what we call waves, these waves like a domino effect create the sea and tides which we know today.

If you think that the effects of the moon's gravity only effect the surface of the water, then I got some news for you.

Originally posted by battl3star
reply to post by dashen

 

Think it may be because the moons effect is only temporary as the tide follows the moons orbit so any poor dinosaur left on the other side would die

Not sure to be honest

They may have just slept at the moons weakest gravitational pull, but if the moon was indeed much closer the effects may have been generally stronger to begin with.

Originally posted by roughycannon
When the dinosaurs were around the earth was more oxygen rich which is why they were so large, there has been tests on insects which are put into an oxygen rich chamber and they grow larger than normal.

The dinosaurs may have been large but so were their muscles and bones which help hold the extra weight.

Its like saying look at a mouse, its tiny but millions of years ago they were huge, how is this possible they were maybe a 100 times bigger...

Cue: lets say an elephant, its far bigger but has bigger muscles and bones to compensate, you really should't think about size and gravity when it comes to muscle and bones that control it.

edit on 26-10-2011 by roughycannon because: (no reason given)

Sorry to be a stickler but you may want to fact check your statement.

The Carboniferous period was the epoch of giant insects due to greater atmospheric oxygen content.

By the time of the Dinosaurs oxygen levels were actually lower than they are today...

The low oxygen levels during the Permian Extinction dropped even further during the Early Triassic, leveling off at a little below 15%. (Modern percentages are at 21%). It stayed near this level for almost 5 million years, from 245 to 240 millions of years ago.

The Triassic Period

Ill be back to this tomorrow gotta go to bed but not agreeing with some of the comments on here!

The only theory that adequately explains the gigantism of the dinosaurs is the Gravity Theory of Mass Extinction (GTME). Briefly, the theory posits that surface gravity on the Earth (in this case on Pangea) was reduced by the shifting of the core elements (inner/outer cores and lower mantle) in response to the coalescing of the continents forming Pangea. When continents move latitudinally, they would alter the Earth's angular momentum if there were no compensating action. The Law of Conservation of Angular Momentum mandates that this cannot happen to the Earth without some external torque. Therefore, something had to happen to offset the continental movement's change of angular momentum. GTME posits a shift of the core elements away from Pangea as the compensating action.

A movement of the core elements away from Pangea would necessitate a reduction of surface gravity on Pangea. The rapid breakup and dispersal of Pangea 60 to 70 mya would have caused an increase in surface gravity, gradually and eventually causing the extinction of the dinosaurs (except birds, of course).

I know from my research that scientists expect that the partial pressure of oxygen in air was higher, close to 26%, during the Period preceding the Jurassic period. I believe the larger animals evolved during the period preceding the dinosaurs, and then a long drawn-out extinction took place when the levels dropped.

ATMOSPHERIC OXYGEN, GIANT PALEOZOIC INSECTS AND THE EVOLUTION OF AERIAL LOCOMOTOR PERFORMANCE

Recent geophysical data as well as theoretical models suggest that, to the contrary, both oxygen and carbon dioxide concentrations have changed dramatically during defining periods of metazoan evolution. Hyperoxia in the late Paleozoic atmosphere may have physiologically enhanced the initial evolution of tetrapod locomotor energetics; a concurrently hyperdense atmosphere would have augmented aerodynamic force production in early flying insects. Multiple historical origins of vertebrate flight also correlate temporally with geological periods of increased oxygen concentration and atmospheric density.

I believe that oxygen concentration and atmospheric density might have more to do with how larger dinosaurs and other creatures were able to develop the structural integrity to handle such enormous weight. Just a theory, if I can find the study, I believe a scientist in the last 20 years raised some fish in a tank where he raised the partial pressure of oxygen and they grew to enormous sizes. But I will have to check my notes because I cannot seem to find the link.



also, it has been found in the case of fish, that smaller fish consume more oxygen than larger fish. Might also be important, we don't really know the metabolic rate of dinosaurs. A lot of theories, but I don't know of any definitive evidence of the case for a slow metabolic rate either.


But yeah I like the gravity theory as well, my guess is it will turn out to be a combination of things that went right to allow dinosaurs to thrive.

According to a recent book 'Biology of the Sauropod Dinosaurs':

"For the most part, geological reasons for sauropod gigantism can be discounted because none of the environmental parameters of the Mesozoic, for example, atmospheric oxygen content, are reflected in changes in sauropod body....."