How Did Planet Earth Sustain Dinosaur Life For Over 100 Million Years?

This is just a random question that popped into my head just now. I guess a lot of them were meat eaters so that was a good form of population control and would have kept the ground fertile. I am surprised that vegetation levels could have sustained the plant eating dinosaurs for so long though. I know there is no specific answer to what their population levels were as a whole during this time, but i could only assume that billions of them roamed the land over that period. 100 million years is a hell of a long time.

reply to post by Hydrawolf


Global warming of course.

It was a tropical paradise of monster teethed lizards and crazy plants.


Good question in my opinion.

It is weird, isn't it?

Homo sapiens are said to be 200,000 years old, in our current evolutionary expression. Homo sapiens - 200,000 years old, but civilization? Oh, just 6,000 years. Yea......something doesn't add up.

Then you think of dinosaurs. Not only did they roam the earth for hundreds of millions of years......but they DIED OFF hundreds of millions of years ago too. That is just so long. Weird when you think of it.

To be honest, the dates of evolutionary events have always seem fishy to me.

reply to post by liejunkie01


Thanks, and i am sure that after 100 million years a few of them dinosaurs with the larger brains were a bit smarter than we give them credit for.

reply to post by Hydrawolf


Its amazing how eco systems balance, but they do. Too many cows and the grass depletes, and the cows starve off until the grass comes back, and they eat well again with a lower population.

Hydrawolf
I am surprised that vegetation levels could have sustained the plant eating dinosaurs for so long though.

Dinosaurs did't cut down trees to create paper and build things. Imagine how many more trees would be on this planet it f there were no humans. I imagine they also did not waste food like humans do today. They probably bit off exactly what they could chew.

reply to post by Hydrawolf


Greater oxygen content levels in the atmosphere

2nd

No plant eater, was left alone long enough, to eat like there isn't anything in the world, out there that can ruin its day...
The natural balance, will be causing carnivorous specimens, to create constant risk of herbivores becoming lunch, that will move up all stressed out animals to prevent them from eating in peace, making them move on around the area's being stealthy, and letting plant life grow back, before it's gone.

The dinosaurs didn't farm any fields, so fertilizing became a part of nature's tasks, that has it's own ways of making sure that dead remains were also remaining to fertilize the plants and trees.

A world filled with trees, and a lack of lumber jacks.

Good question! Maybe because dinosaurs DIDN'T build nuclear reactors on the Pacific Ocean and radiate themselves into extinction. And they didn't hoard money either! Pretty smart critters. Maybe we could learn a thing or two.

reply to post by supermarket2012


Actually, our current form of civilization started about 14,000 years ago, not 6. We started to develop techniques for agriculture and domesticating animals, which is the roots of modern day civilization.

And the last of the Dinos died out roughly 65 million years ago, not 100's. The earth had a period of little animal life, there was still small mammals that were present, but the Cenozoic period, or the age of mammals, started roughly around the same period, maybe a couple hundred thousand years after the extinction event that wiped out the dinosaurs.

Me thinks this is best explained....

reply to post by Arnie123


and,

The Lion King - The Circle Of Life (HD)
www.youtube.com/watch?v=8zLx_JtcQVI
www.youtube.com...


and this:

NOVA scienceNOW : 30 - Trex Blood
www.youtube.com/watch?v=TihDbUxnuqk
www.youtube.com...

this is the best short answer i have ever seen. hope it helps.

To give the shortest possible answer: because they could. It may sound silly, but this is accurate to a point, the size of an animal is limited by the environment, and without limitations, it can and will grow unchecked. Obviously no such limitless environment exists on Earth, there are always such things to consider as food availability, gravity and oxygen. There are also certain advantages to being really big which may be causal to growing big or simply a beneficial side effect.

Before I go into the reasons dinosaur were big, I must point out that most dinosaurs were not exceedingly big. Such iconic genera as Tyrannosaurus, Triceratops, Ankylosaurus, Anatotitan and Stegosaurus were no more massive than modern African bush elephants, some were even smaller! It's only sauropods like Brachiosaurus, Apatosaurus, Diplodocus, and later the titanosaurs, that overgrew these limits. Even still, these dinosaurs never reached the calculated theoretical size limit for terrestrial animals (100 000 - 1 000 000 kg). Once you reach this limit, the animal becomes too large to move or even support its own weight. Since the megasauropod Amphicoelias has been estimated to have reached a size close to this theoretic maximum, it seems sauropods had eliminated all other limits to their growth.

So, why were sauropods so big? Of the list of limiting factors, the first one to tackle is oxygen. Atmospheric Oxygen levels were much lower than today during the Triassic, when the ancestors of dinosaurs evolved. Already back then the ancestors of sauropods were growing bigger than anything else. During the Jurassic period, oxygen levels soared to modern-like levels enabling dinosaurs with their unusually effective air-sac lungs to grow much larger much faster than all the other animals. The Jurassic atmosphere was different from the present in other ways, too. Global temperatures were high and level of CO2, which not only warms the temperature but also is required by plants to grow, was multiple times the modern amount.

While this may make the Jurassic seem like a time of plenty, which would neatly explain gigantism, it has actually been shown that the diet of the sauropods was nutrient-poor. So why would they grow so big if their diet was so poor? Actually, modern megaherbivores provide an explanation: the larger an animal is, the larger digestive system it has. The larger the digestive system, the longer it can digest its food, making use of poorer browse or graze. The sauropods had immense guts acting like fermentation chambers which extracted all the needed nutrients from plentiful but nutrient-poor plants the other dinosaurs could not exploit. By tapping into an otherwise unused food resource allowed them to thrive, even though it meant growing into a humongous size.

Obviously growing so big caused major limitations. A sauropod could not run, nor jump, nor even fall down without risking serious injury. However, being so immense meant they did not have to. Even the largest carnivores of the time would have had great difficulties killing a full-grown megasauropod. That difficulty was amplified by the fact that sauropods lived in groups and could use their long tails as effective weapons. It was much less trouble for an allosaur to go hunting smaller but still massive prey, such as Iguanodons.

It has also been suggested that sauropods took advantage of their giant size in another way: to keep their body temperature stable. When an animal becomes sufficiently large, its sheer volume is able to retain heat effectively without the animal having to produce its heat itself or worrying about losing most of its body heat in cool conditions. This is known as gigantothermy, and certain cold-blooded marine animals take advantage of this phenomenon today. Analysis of different types of dinosaurs suggests that while a lot of dinosaur groups seem to have been able to regulate their body temperature like modern mammals and birds, sauropods weren't among them. Since they were cold-blooded and immensely massive, they would have been perfect candidates for gigantothermy.

Source(s)

www.miketaylor.org.uk...
www.bioone.org...
scientists.dmns.org...

so in short it was a combination of things which allowed them to live and thrive.

I'm pretty sure it wasn't extra oxygen or warmth. If we had more of that we would just be bigger and warmer. I believe it has to do with balance - with one species never out populating another to a great extreme - or not causing the extinction of many on a global scale. No overconsumption means no larger impact. There is plenty of room for life if a species only uses what it needs (a food source/shelter/defenses to protect those things).

If each species is kept in check by predators and all species have a predator there is a balance. Species died out and the stronger survived but I believe the abundance of life at that time is due to that checks and balances nature provides.

With regard to dinosaurs being extinct isn't it common knowledge that some survived? Crocodiles, seagulls, pelicans, snakes, lizards, turtles...

Its also important to remember that species of dinosaur were always going extinct and new ones evolving during this time period. It wasn't always the same guys hanging around.

There is evidence of rapid die off of certain species that we gather happened because of changing climates or what have you. I'm sure many species did actually starve out, others may have contracted disease, some were simply pushed out of their habitat by new species moving in.

It was a very complicated ecosystem.

GAOTU789
reply to post by supermarket2012

 

Actually, our current form of civilization started about 14,000 years ago, not 6. We started to develop techniques for agriculture and domesticating animals, which is the roots of modern day civilization.

And the last of the Dinos died out roughly 65 million years ago, not 100's. The earth had a period of little animal life, there was still small mammals that were present, but the Cenozoic period, or the age of mammals, started roughly around the same period, maybe a couple hundred thousand years after the extinction event that wiped out the dinosaurs.

edit on 4-10-2013 by GAOTU789 because: (no reason given)

Can you point me in the direction where I can learn more about what we currently know as far as civilization development leading up to Sumeria?

Everything I learned in college basically said that it (not literally of course) happened overnight.....referring to the creation of Sumeria. I was taught that we have no direct evidence that shows us how we got from point A to point B.

This is something that interests me greatly, so I'd love to learn more on the subject.

supermarket2012

GAOTU789
reply to post by supermarket2012

 

Actually, our current form of civilization started about 14,000 years ago, not 6. We started to develop techniques for agriculture and domesticating animals, which is the roots of modern day civilization.

And the last of the Dinos died out roughly 65 million years ago, not 100's. The earth had a period of little animal life, there was still small mammals that were present, but the Cenozoic period, or the age of mammals, started roughly around the same period, maybe a couple hundred thousand years after the extinction event that wiped out the dinosaurs.

edit on 4-10-2013 by GAOTU789 because: (no reason given)

Can you point me in the direction where I can learn more about what we currently know as far as civilization development leading up to Sumeria?

Everything I learned in college basically said that it (not literally of course) happened overnight.....referring to the creation of Sumeria. I was taught that we have no direct evidence that shows us how we got from point A to point B.

This is something that interests me greatly, so I'd love to learn more on the subject.

There is plenty of evidence on our migration with only a few differing theories such as did people cross over from Asia to the America's by the land bridge or did they possible come in boats. You can basically track human migration out of Africa however.

There's a few squirrely things about extremely old fossils popping up where they shouldn't be but that may just be because science has not caught up, or enough evidence hasn't been found yet.

reply to post by Hydrawolf

How did Earth sustain mammalian life for 195 million years?

What's so special about dinosaurs?

Darn browser. Double post.

I think what you're asking is was there another intelligent species that came and went somehow? Doubtful. I think it'd show in our records. It's probably impossible for it to be missed. Think: Could humans disappear from the record in the next million years? Not likely, unless God himself came here and wiped away all the evidence and clues.

BUT it'd make a fun science fiction story