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jesspy

dino blood

15 posts in this topic

I see the poll on this but Is it possiable to evolve from cold to warm blood?

Edited by jesspy

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There is a question that has plagued palaeontologists interested in dinosauria for as long as the animals have been studied; were dinosaurs endotherms (warm-blooded) or ectotherms (cold-blooded)?

Today, endothermy is seen in mammals and birds but not in reptiles and is actually little to do with the temperature of the blood. An endotherm generates heat, climate-controlled internally to produce perfect conditions for the biochemistry inside the animal. This is because most biochemical reactions are catalysed, usually by enzymes, and those enzymes operate most efficiently in a narrow temperature range. Unfortunately, this level of control uses an enormous amount of energy so endotherms need to eat a great deal more than ectotherms.

Terrestrial ectotherms use the warmth from the sun to heat their bodies to optimum temperature and use shade, water or other means to lose heat should that become necessary. Consequently, ectotherms are not 'all-weather' animals and are only active in a fairly narrow range of conditions. The huge advantage of ectothermy is that it requires vastly less energy and therefore vastly less food.

more on this at

bbc

ps.tommy(mod)...got the link :tu:

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There is a question that has plagued palaeontologists interested in dinosauria for as long as the animals have been studied; were dinosaurs endotherms (warm-blooded) or ectotherms (cold-blooded)?

Today, endothermy is seen in mammals and birds but not in reptiles and is actually little to do with the temperature of the blood. An endotherm generates heat, climate-controlled internally to produce perfect conditions for the biochemistry inside the animal. This is because most biochemical reactions are catalysed, usually by enzymes, and those enzymes operate most efficiently in a narrow temperature range. Unfortunately, this level of control uses an enormous amount of energy so endotherms need to eat a great deal more than ectotherms.

Terrestrial ectotherms use the warmth from the sun to heat their bodies to optimum temperature and use shade, water or other means to lose heat should that become necessary. Consequently, ectotherms are not 'all-weather' animals and are only active in a fairly narrow range of conditions. The huge advantage of ectothermy is that it requires vastly less energy and therefore vastly less food.

more on this at

bbc

ps.tommy(mod)...got the link :tu:

I wonder if the dinosaurs actually evolved from both mammals and reptiles?....they were after all the earth's most successful species ever. prhaps when we find evidence that the larger sauropods were not egg layers.

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Obviously, ectothermes had to at some point evolve into endotherms, we are here after all.

It is not necessary for all creatures to evolve the same solution to the same difficulty, nor for all animals to evolve it at the same time. Evolution is not yet over, You are not the be all end all of the species. Your great grandchildren will be better adapted to the enviroment than you are, even if only incrimentaly.

Maybe all the birds have a commen ancester who was an endotherm, or more likely, they had an ectothermic ancester that possessed an inclination to endothermy.

Edited by Lord Umbarger

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As mentioned on another thread, the family of Archosauria includes birds, crocodilians and dinosaurs. Birds are Endos, Crocs were ectos, so there is no reason dinos couldn't have both. Some small dinos clearly seem to be endothermic like the very similarly structured birds, but the large dinos were probably all ectotherms. Large reptiles do not readily lose their body heat. And some had spinal sails which indicate the need to thermoregulate.

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some had spinal sails which indicate the need to thermoregulate.

thats a good point...dc

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thats a good point...dc

yes the spinal sail does create a problem...another problem has been created by the sudden announcement of a swiss reareach team who have discovered grass spores in dung laid by one of the larger sauropods that lived during the late jurassic. whoops...I guess the book is going to have to be edited again :no:

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yes the spinal sail does create a problem...another problem has been created by the sudden announcement of a swiss reareach team who have discovered grass spores in dung laid by one of the larger sauropods that lived during the late jurassic. whoops...I guess the book is going to have to be edited again :no:

another good point fantazum :tu:

A study of fossil dinosaur dung has for the first time confirmed that the ancient reptiles ate grass.

thats from bbc site at link

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Until we know more about their lifestyles, we won' know for sure, but based on theories, smaller carnivorous dinosaurs could of been warm-blooded...

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Until we know more about their lifestyles, we won' know for sure, but based on theories, smaller carnivorous dinosaurs could of been warm-blooded...

do you know that there are a few scientists who dispute the idea that dinosaurs were animalian at all?....amazing. and there are a growing number of paleantologists who question whether all dinosaurs were egg layers.

I suspect that many dinosaurs had both ectothermic and endothermic physiology.Especially the larger ones. The dinosaurs lived for perhaps more than 150 million years and with such a tremendously long development period they could have evolved both mammalian and reptilian features. Dont forget that there are creatures alive today that have both mammalian and reptilian features.

The larger sauropods were very highly evolved and grew to incredible sizes and if we think of these creatures as being alive today we immediately wonder how much food they had to eat to maintain their great bulk. Well if they had both mammalian and reptilian features their food demand would not have been so massive as for instance, an elephant of equal size. (use your imagination)

The only aspect of these great creatures I have difficulty understanding is how they grew to such apparent great weight and size. Our environement controls our development and pace of evolution and no living thing on this planet can defy the constraints placed on it by nature.

Some natural phenomena allowed the dinosaurs to grow to such gigantic sizes....but what?

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Lot's of people believe that some smaller species (raptors) had feathers or even possibly fur. And if they did they would most likely make their own bodyheat in order to actually have something to use the feathers for, making them warm blooded. (unless this was a phase in their evolution between reptile and bird) Also there is now a popular belief that dinosaurs were mammals, not reptiles, making them warm blooded.

Some scientists now say that reptiles make some of their own bodyheat by eating, making them technicaly not cold blooded.So mammal, reptile, bird, or whatever, some of the dinosaurs were warm blooded in my opinion.

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It really depends on the dinosaur. Like extremely large mammal species, the cold-blood/hot-blood distinction would become blurry in large dinosaur species, whose internal body volume is large enough to hold a considerable amount of heat.

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Possibly the longest, but unquestionably one of the largest of the Theropod dinosaurs (Spinosaurus Aegyptus of Jurassic Park III fame), was equipped with a large sail, as were other dinosaurs and earlier reptiles like dimetrodon. These can be seen on living lizards as well, and strongly suggests then, that these dinos were ectotherms, who used their sails to rapidly heat, or cool their blood. With the exception of the small theropods, that seem to have insulating fibres or even feathers, most dinosaurs were probably "cold blooded", but this makes them no less succesful. Consider their close relatives the crocodilians, (both are archosaurs), which have done perfectly well as cold bloods, long before, and long after, the age of dinosaurs.

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Consider their close relatives the crocodilians, (both are archosaurs), which have done perfectly well as cold bloods, long before, and long after, the age of dinosaurs.

The problem with that is that the crocodilians have only existed in, at the coolest, warm temperate climate water. Not to mention that they are ambush predators (where a burst of speed rather than endurance is important), and many of the crocodiles are, or were, large enough to maintain body heat by their sheer volume.

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Yes, but crocs adapted to also fill the niche of land dwelling theropod dinos after the dinos died, developing hoof-like feet and running on just their hind feet, looking much like a Baryonyx.

I have tried to catch desert monitors in Iraq, and they can run for a very long time and exhaust the average person. It is only possible in a HUMMV. They are as active as any mammal. Of course, its a warm place, but even antartica was a lot warmer, and you have Tuatara in a pretty cold climate in New Zealand.

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