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Author Topic: Dinosaur evolution - were they warm blooded ?  (Read 19244 times)

Offline Scarlet King Snake

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Dinosaur evolution - were they warm blooded ?
« on: 31/05/2004 23:23:47 »
Is there any evidence of dinosaurs possibly being warm blooded or even being mammals?


 

Offline gsmollin

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #1 on: 01/06/2004 02:02:35 »
Dinosaur morphology was wrong to have been mammals. To my knowledge, no one thinks dinosaurs were mammals. The warm-blooded question remains a topic of debate, however. All the evidence is circumstantial. Birds are warm-blooded, and reptiles are cold-blooded. Dinosaurs resembled both, and seemed to act like both. Maybe the answer is somewhere in the middle, with some being cold, and some having some temperature control. Also, dinosaurs ruled the animal kingdom for ~100 million years, and evolved considerably during that time, so cold or warm may have changed both by species, and timewise.
 

Offline Scarlet King Snake

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #2 on: 02/06/2004 22:05:11 »
Actually I brought this up because there is still a large debate as to whether they'e warm or cold blooded.

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Offline qpan

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #3 on: 02/06/2004 23:35:01 »
Its hard to imagine warm blooded reptiles - but maybe some/all dinosaurs were and thats why they became extinct (would probably be highly specialised and successful in their respective environments, but useless when environment changes).

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Offline Scarlet King Snake

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #4 on: 03/06/2004 04:04:02 »
Its quite possible due to information received from the preserved heart of a Thescelosaurus since it resembles more of a mammals heart or a birds not a reptile.

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Offline qpan

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #5 on: 03/06/2004 17:43:43 »
In what way was it preserved? Would have had to survive at least 65 million years! Thats one hellava preservative!

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Offline Scarlet King Snake

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #6 on: 03/06/2004 22:35:27 »
It was actually fossilized heres the site.
newbielink:http://www.enchantedlearning.com/subjects/dinosaurs/news/Heart.shtml [nonactive]

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Offline qpan

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #7 on: 04/06/2004 10:21:48 »
Cool-but how exactly does tissue become fossilised (as usually its the bones)? I suppose in rare cases (such as if the dinosaur falls into a bog) and the tissue is preserved, then the tissue might last long enough to be fossilised, but it must be some strange method of fossilisation to be able to preserve the structure of the tissue (especially the internal detail too).

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Offline tweener

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #8 on: 04/06/2004 14:44:14 »
This is very interesting.  There's more information and images here:
http://www.dinoheart.org/insideout/index.html

I don't know what I'm looking for, but some of those images seem a real stretch to me.  Very interesting though.

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Offline chris

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #9 on: 07/06/2004 05:38:41 »
Dinosaurs are close relatives of birds and reptiles. The closest living reptile ancestor is the crocodile. But significantly, whilst birds have a 4 chambered heart like our own, reptiles have a 3 chambered heart (2 atria with a single ventricle), and crocodiles have a 4 chambered heart (like ours) but with an extra-pulmonary branch (the so-called right systemic artery) which allows blood to bypass the lungs under low-oxygen conditions.

Where dinosaurs fit into this jigsaw is a matter of considerable debate. I spoke with a palaeontologist about this today who told me that the fossilised heart discovered recently is now not believed to demonstrate a 4 chambered architecture as claimed previously. Instead the identified morphology is thought to be artefactual. The jury is therefore still out.

Similarly, we still do not know whether dinosaurs were hot of cold blooded. It is likely that many of the large meat-eaters were warm-blooded; indeed when they emerged from the egg many dinosaurs like Tyrannosaurus were probably feathered to preserve heat. However, as they grew, the need for heat conservation became less of a problem and in fact heat-loss became more of a priority. So-called 'gigantothermy' takes over whereby an animal is so big that it literally cannot lose heat fast enough. This is thought to have driven the development of heat-loss mechanisms like long necks and skin plates doubling as heat-sinks. The evidence that this is the case comes from modern-day big crocodiles. Large specimens maintain an even body temperature continuously, despite (in theory) being cold blooded.

Chris

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Offline Scarlet King Snake

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #10 on: 08/06/2004 04:38:34 »
Very helpful thank you Chris.

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Offline Broca

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #11 on: 12/06/2004 18:54:24 »
A fossil of a T-Rex was found in S. Dakota.(named Samson) It is touted as the most complete T-Rex skeleton ever found. The article I read also talks about the fact that the orbits are found further back on the side of the head lending us to believe that it was NOT the horrid meat eating preditor that we have long thought. I don't think this article convinced me that the T-Rex was a warm fuzzy kind of guy, but it was interesting.

http://www.carnegiemuseums.org/cmnh/exhibits/carnegiesdinosaurs/paleolab.htm
 

Offline Exodus

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #12 on: 30/06/2004 08:14:24 »
quote:
Originally posted by Broca

A fossil of a T-Rex was found in S. Dakota.(named Samson) It is touted as the most complete T-Rex skeleton ever found. The article I read also talks about the fact that the orbits are found further back on the side of the head lending us to believe that it was NOT the horrid meat eating preditor that we have long thought. I don't think this article convinced me that the T-Rex was a warm fuzzy kind of guy, but it was interesting.

http://www.carnegiemuseums.org/cmnh/exhibits/carnegiesdinosaurs/paleolab.htm




hmmm, nah. You don't evolve an animal with such powerful jaws and teeth for it to ***** foot around and scavenge. Most scavengers are fairly small, just think how much T Rex would have to scavenge to stay alive? intersting all the same.
« Last Edit: 30/06/2004 08:14:56 by Exodus »
 

Offline sonofjackass

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #13 on: 20/08/2004 21:34:01 »
ok, you know, i used to believe that T.rex was a powerful predator, but you know, actually jack horner's evidence is pretty good, if you dont know about it, i'm gonna try to explain it
1. the t.rex femur is shorter than the tibia and perone, so, this makes it slow. this is why ostriches are faster than humans, even when human legs are almost as long as the ones in ostriches. this made t.rex a slow runner, in fact, its possible than t.rex couldnt even run, instead, the fastest locomotion for a t.rex would be something like a fast walk.
2. not all the scarvangers are small... and in fact, they have to be big and more powerfull than predators. here in mexico, when a hawk kills its prey, it has to eat fast, because the bigger and stronger vulture is always there. the vulture is stronger, and bigger cause it has to scare the hawk, not because it has to kill the pray. this also happens with the hyena, which is bigger than the cheetah only because it has to scare the cheetah to succesfully scarvange.
3. guess who has the most powerfull jaws in africa today? a scavanger, the hyena. the scarvangers have to have a powerfull bite, to be able to esat the left overs, such as bones.
i hope this was useful, and excuse my english... by the way, dinosaurs were warm blooded

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Offline Raedon

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #14 on: 11/11/2004 09:53:41 »
I wonder if they tasted like Chicken or Turkey [8D]


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Offline johanna

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #15 on: 21/04/2005 03:13:45 »
Are t rexes warm blooded? Did they amniotic eggs? Did they sing to their young? Please help me answer theses questions, it's for school!

johanna
 

Offline ADD HAHAHA

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #16 on: 21/04/2005 04:04:53 »
scientists think mammals came from a dog sive dino looking thing. it produced milk, layed eggs, partnared 4 life, protective parents, and had hair!!!

http://www.abc.net.au/dinosaurs/tv_series/default.htm this should help

scientist think t rex had amniotic eggs, communitated(sang) to their young and were a mix between cold n warm blooded.

i think trex ran down its pray, suprised its pray, and hurased its pray. i also think dinos r MORE related to birds then reptiles(atleast the carnivourse) the way their hips n backs r structsured they r similer to an ostrige also the way they balance is like a bird.


 

Offline daveshorts

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #17 on: 21/04/2005 11:32:39 »
If this is the same walking with dinosaurs that came out on the BBC a few years ago, you may well want to take it with a pinch of salt. It was dreadful for mixing good science with stuff that is just wild speculation, it is possible there is evidence for amniotic eggs, the cold vs warm blooded thing is still a bit contraversial, but noone has any way of finding out whether they sang to their young or not!

Saying scientists think something is rather weak as all you need is one scientist to speculate slightly wildly, and an unscrupulous TV producer to run with it, and you suddenly find that scientists thing that black is white and up is down.
 

Offline ADD HAHAHA

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #18 on: 21/04/2005 18:00:17 »
wat ever!

i think dinos had niether warm or cold but possible a mix it needs to warm up but it can also control the temputer and pressure.

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Offline Andrew K Fletcher

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #19 on: 23/04/2005 09:25:42 »
Actually I posted it first :)

For many years dinosaurs were thought to be cold blooded. The general concensus now is that they were in fact warm blooded. There was after all a 50% chance of getting it either right or wrong :)Still even the brightest light will cast a shadow and a stopped clock can be correct twice a day.

But this adds some serious considerations with relatively un-elevated reptiles today. Is there a connection between the heat generated in warm blooded creatures and their more upright posture than the relatively un-elevated reptiles today? For example, does a giant monitor lizard generate more heat than say a gator or a crock?

Andrew


Actually I brought this up because there is still a large debate as to whether they'e warm or cold blooded.

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« Last Edit: 23/04/2005 09:29:30 by Andrew K Fletcher »
 

Offline Andrew K Fletcher

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #20 on: 23/04/2005 09:35:15 »
Gpan
There are many examples of plants and trees, so why not internal organs? Maybe we have not even scratched the surface "pun intended"

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Offline Exodus

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #21 on: 25/04/2005 14:10:10 »
Andrew, remember that when we are looking at plants, they are made up of cellulose which is in fact quite a hardy material. Its longevity in the ground before it is eventually broken down by bacteria has allowed fossil imprints of structure. As i'm sure you are aware, animal cells are more easily broken down and hence are less likely to remain within the fossil record. You must also remember that plants were also significantly more copious than animals so there are likely to be a greater number of plant fossils than animal. Bones of animals are our only real record as they often undergo mineralisation within the ground.
 

Offline Andrew K Fletcher

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #22 on: 26/04/2005 19:21:44 »
Fair point Exodus

But we really aught to take a look at the mummified remains in South America and China, before we presume that the internal organs cannot be preserved. Maybe they became desiccated by the deserts, as did the discovered mummified remains.

Or maybe the dinosaurs ate a lot of food with artificial preservatives in it :P


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Offline daveshorts

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #23 on: 26/04/2005 19:32:03 »
Soft tissues in animals do fossilise very rarely, or at least their imprints do, but I  would have thought that they would end up very squashed and hard to interpret. Add this to how increadibly rare they are and you have big problems making general conclusions.
 

Offline Isambard

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #24 on: 28/04/2005 04:30:59 »
Dinosaurs belonged to the Saurischia (Sauropoda and Theropoda) or Ornithischia. Theropoda were without a doubt warm blooded, at least the more advanced forms.
What about the Ornithischia? There is very good reasons to believe some of them, like Leaellynasaura, were warm blooded too.
 

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Re: Dinosaur evolution - were they warm blooded ?
« Reply #24 on: 28/04/2005 04:30:59 »

 

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