Much of it stems from the hypothesis that Dinosaurs were Endothermic (Cold-blooded).
I apologize for the error .. I meant Ectothermic.
MaLiCe
JoinedPosts by MaLiCe
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9
Dinosaurs: reptile or not?
by BlackSwan of Memphis inmy 4 year old has a strong interest in dinosaurs lately.
well, it's been lasting for a good few months.. i've bought books and checked some out of the library, done internet searches.. the thing is some of the research/books say, 'yes, dinosaurs were reptiles.
' other sources say they weren't.. i'm wondering if any of you have researched this topic and what you came up with in regards to this specific topic.. i'm not sure what to think.. .
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MaLiCe
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9
Dinosaurs: reptile or not?
by BlackSwan of Memphis inmy 4 year old has a strong interest in dinosaurs lately.
well, it's been lasting for a good few months.. i've bought books and checked some out of the library, done internet searches.. the thing is some of the research/books say, 'yes, dinosaurs were reptiles.
' other sources say they weren't.. i'm wondering if any of you have researched this topic and what you came up with in regards to this specific topic.. i'm not sure what to think.. .
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MaLiCe
Indeed ...
There still exists to this day much controversy regarding this issue.
Much of it stems from the hypothesis that Dinosaurs were Endothermic (Cold-blooded).
Before approximately 1960, almost all scientists believed the theory that their temperature was determined by that of the external environment. Scientists thought this because they had decided that dinosaurs were reptiles, and all modern reptiles are cold-blooded. (It should be noted that the term "reptile" has fallen out of favor in the modern, cladistic view, denoting as it does a paraphyletic group; however, most people still understand what is meant by a reptile, and I will use the term throughout in its traditional sense, making no pretense that it designates a natural clade.) Alligators and crocodiles are the most closely related non-dinosaurian archosaurs, and they are cold-blooded. Then people began to look further, and some of them decided that it was not so easy. Dinosaurs were unusual reptiles at best. They do not look like modern reptiles. They did not walk like modern reptiles. It had been suggested almost a century ago that birds were the direct descendants of dinosaurs, and they are indisputably warm-blooded; in fact, in the cladistic view, birds are dinosaurs. Maybe there was more to the story.
Several scientists proposed the "inertial homeotherm" idea. They said a big dinosaur could keep an even body temperature just because it was so big. According to Colbert and colleagues, a medium-sized dinosaur exposed to day and night temperatures similar to those found in Florida today would take 86 hours to change its temperature by 1°C. They based their estimates on experiments with alligators tied up out in the sun. Mesozoic climates were far more equable than they are now. Clearly, by moving from sun to shade, as modern ectotherms do, a fine degree of temperature control could be achieved without invoking a high metabolism.
Conclusion: Indisputable evidence does not exist for warm-bloodedness in all types of dinosaurs. However, it is highly unlikely that all dinosaurs were cold-blooded, either. Morphological and postural evidence, bone histology, ecological information, and brain/body size relationships indicate that we cannot make sweeping generalizations about dinosaurian metabolism. Most likely it varied between groups. Dinosaurs spanned the spectrum from inertial homeotherms to active, endothermic birds.
But that's just me ... I always encourage anyone to do their own research ...