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Gravity vs. Dinosaurs
Misanthropic
Registered User regular
Registered User regular
We know dinosaurs of all kinds existed. We have found their fossil remains everywhere. They existed millions and millions of years ago and were huge and then they died in a cataclysmic event. The common belief is something very large collided with earth.
That is all fine and good... right?
Well, I have been wondering about some things for a while. There are two questions that have stood out in my head that I can't find non-crazy answers to:
1) Assuming gravity was the same then as it is now, how did they exist?
These creatures were enormous. So large that some even came close to the size of a Blue Whale - and a great many existed solely on land or even in the air. Given the size of their bones we can extrapolate weight ranges for these animals. When you do this you run into a whole host of problems: some dinosaurs would seem to be incapable of flight, some dinosaurs would require hearts that would be disproportionately large or impossibly large, some dinosaurs would not be able to lift their heads - ruling out the main advantage of long necks, and so on and so forth.
And this leads into my second question...
2) Given the obvious advantages of a large size, why don't we find land and air animals as large as the dinosaurs today?
Being huge has many things going for it. It makes it harder for you to be hunted and killed. You can pick food from hard to reach places. You have the benefit of being able to stop and rest if needed. You can more easily prey on other, smaller animals. So simple Darwinism would seem to lead us to dinosaur sized animals today, especially given the fact that we have proof dinosaur sized animals existed before (namely dinosaurs).
The only way I can answer these two questions is, well, silly and flies in the face of all our currently accepted science. If dinosaurs existed, which we know they do, then gravity must have been less in their time than it is in our time. It allows for such huge creatures to exist solely on land and accounts for the fact that we don't have dinosaur sized land animals now.
But I realize it is a crazy notion. Is there a piece to the puzzle I'm missing?
That is all fine and good... right?
Well, I have been wondering about some things for a while. There are two questions that have stood out in my head that I can't find non-crazy answers to:
1) Assuming gravity was the same then as it is now, how did they exist?
These creatures were enormous. So large that some even came close to the size of a Blue Whale - and a great many existed solely on land or even in the air. Given the size of their bones we can extrapolate weight ranges for these animals. When you do this you run into a whole host of problems: some dinosaurs would seem to be incapable of flight, some dinosaurs would require hearts that would be disproportionately large or impossibly large, some dinosaurs would not be able to lift their heads - ruling out the main advantage of long necks, and so on and so forth.
And this leads into my second question...
2) Given the obvious advantages of a large size, why don't we find land and air animals as large as the dinosaurs today?
Being huge has many things going for it. It makes it harder for you to be hunted and killed. You can pick food from hard to reach places. You have the benefit of being able to stop and rest if needed. You can more easily prey on other, smaller animals. So simple Darwinism would seem to lead us to dinosaur sized animals today, especially given the fact that we have proof dinosaur sized animals existed before (namely dinosaurs).
The only way I can answer these two questions is, well, silly and flies in the face of all our currently accepted science. If dinosaurs existed, which we know they do, then gravity must have been less in their time than it is in our time. It allows for such huge creatures to exist solely on land and accounts for the fact that we don't have dinosaur sized land animals now.
But I realize it is a crazy notion. Is there a piece to the puzzle I'm missing?
Misanthropic on
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All sorts of crazy shit that doesn't seem probably exists in rain forest today...
That is why you grow bigger... assuming gravity allows you to.
Which goes back to my whole gravity problem.
Which just makes you a bigger target for said atatl-chuckers. Seriously, those things can punch right through plate armor, being bigger really isn't going to help you much.
Even as far back as before the last few ice ages you had some HUGE land animals. Not dinosaur sized, but they were definitely trending that way. After that there's a downward trend; most of the larger animals went extinct because of climate changes and said-atatal chuckers.
Its actually kind of morbid. Put extinction rates on one map, then human spread on another map. They match up pretty well. So either we killed off everything in our path as we spread across the globe, or we used the chaos to sneak in.
Evolution and survival don't work that way. It's not as if woolly mammoths could just decide "Fuck it, I'll double my size, that'll show those pesky humans!"
Edit: Also the aforementioned uselessness of large size alone against pack animals killing and eating you.
In other words, being big is not necessarily a fitness advantage.
Also, I don't get your point about gravity. Large dinosaurs obviously got around the problem by evolving to have more muscle and thicker bones that can carry their body mass. Not to mention the fact that most of them walked on four feet, which does make things easier (I don't know if you ever tried it).
I realize it doesn't work like that. Smaller animals get eaten easier, making larger animals more prevalent. I get it. Still doesn't rule out huge pack animals. I mean, why not three times the size of an elephant, without the gravity problem?
Because we eat them.
Growing bigger, as Quid mentioned, is not something you just randomly decide. It's something that is done when it gives you an evolutionary advantage. In the case of dinosaurs, it was a kind of vicious cycle:
1) Carnivores hunt the smaller herbivores
2) Larger herbivores survive and have large offsprings, increasing the average size of their population
3) Larger herbivores can fight off smaller carnivores. Larger carnivores survive and have large offsprings, increasing the average size of the population.
4) New, larger carnivores hunt the smaller of the new, larger herbivores. Repeat from step 1.
This happened over and over for a hundred million years or more, culminating in the gigantism of popular dinosaurs.
For this to happen again today, you'd need the same evolutionary pressure. Which does not exist anymore. Pack carnivores are predominant today, and they have no problem hunting the larger herbivores. In fact, they prefer it, as the larger ones are both slower and provide enough food for the pack, and their size advantage is negated by the sheer number of faster predators. So the average population size remains stable.
Bones can only get so big, though. Even if they were able to move around without splintering, I'd think they would wear out really quickly.
So size and armor aren't enough. You know what they need? Projectile weaponry.
This really is all there is to it. I mean the Americas had sloths the size of elephants and other huge mammals and once humans came around HEY WAIT THOSE ANIMALS AREN'T THERE NO MO'!
Because they never met a human before.
The force of gravity between two objects is dependent on the gravitational constant, the masses of the two objects, and the distance between their centers of mass. The gravitational constant lives up to its name, and the Earth's radius and mass haven't meaningfully changed since it finished forming (I think the collision that created the moon came before then; if not, then that collision would be the last time. Either way, that was billions of years ago). Thus the force of gravity on dinosaurs per kilogram was the same as it is on us.
Well there you go guys, dinosaurs couldn't have possibly existed.
That's it I'm sticking to the bible now!
What about Behemoth and Leviathan?
King Kong couldn't exist if he was just a scaled-up gorilla. His legs would break under his weight. His lungs wouldn't be able to pick up enough oxygen, so he'd suffocate.
I read an article on this years ago.
Okay dinosaurs and biblical creatures CAN exist, but only if God wants them to.
Thus says the Bible!
As far as the flying dinosaurs goes, the largest ones are believed to have done more gliding then powered flight. Given the wingspans and just general wing size, that would have worked well for them.
Haven't really read more than that random article where they compared a common field mouse to an elephant, but the mouse would essentially have to turn into an elephant to survive at that size. Its legs would snap instantly, and then it'd be a coin toss between a heat stroke and suffocation as cause of death.
There's a certain point where muscle strength and muscle mass intersect. That is to say that you could make a being so strong that it can't lift itself - the weight of the muscle mass is greater than the strength of that muscle mass.
I wouldn't be supposing that the gravitational constant has changed, more that the radius of the Earth has changed or the mass of the Earth.
The point being there is a mass/strength threshold - under which creatures are possible, over which creatures are not - and dinosaurs seem to cross that threshold.
The beginning of this article states it. Now, keep in mind the science in the article may be off and it is an olol internet source, but I don't have the scientific background to tell whether or not the science in it is baloney or not. Hence seeking it out from ya'll.
http://www.freerepublic.com/focus/f-chat/1913389/posts
I think he was wondering at what point the strength and mass intersect.
And freerepublic? REALLY?
During the time of the dinosaurs, the Earth's biosphere was ideal to support megafauna, and the animal kingdom had developed in such a way that being ridiculously huge was not a fatal flaw. Look in the ocean - there's s till plenty of mega-fauna living there, although we did a good job of trying to wipe them out once we worked out how to get at them.
on science
... I don't even know where to begin, but my instinctive reaction would probably get me infracted. Suffice to say, the 'argument' fails simply by assuming that dinosaur muscles would look remotely like ours at a molecular level. Not fucking likely, when you think about it!
By what mechanism would that happen?
If the Earth gains or loses mass, it has to come from or go somewhere. Asteroid impacts are insufficient to cause significant changes in Earth's mass; extinction level events only happen once every several hundred million years, and even those asteroids are on the order of six to ten miles in diameter. Earth's diameter is about four thousand miles, so Earth's volume is on the order of hundreds of millions of times greater than those asteroids'.
How else would Earth gain or lose significant mass?
I once took a dump so huge my weight scale said I lost five pounds.
The earth's rotation has a minuscule effect on gravity.
Also the necessity of ass brains?
Really, who doesn't have an ass brain?
That's not actually true at all--the megafauna in the Americas didn't go extinct due to human predation. There are actually very little confirmed archaeological evidence of human predation of mammoths, for instance. Going off memory (aka I may have just made up these numbers), there are something like 11 archaeological sites in America where the remnants of a mammoth kill has been discovered, and of those, something like 8 or 9 were incidental kills, where the animal had fallen into a tar pit or was somehow otherwise incapacitated and then killed by purely opportunistic human hunting.*
There's more than one theory for the disappearance of American megafauna, including climate change and possibly human-introduced disease. Climate change seemed most plausible to me when I was taking my American archeology course. As a side note, one of the pressures towards massive size was the efficiency of larger bodies at conserving heat, due to their better volume to surface area ratio. As the climate warmed, that pressure disappeared. That factor alone doesn't necessarily explain the decline of megafauna, but I think it's neat.
*In Australia, however, it looks like humans may have killed the shit out of everything.