THE DINOSAURS WERE WARM - BLOODED ANIMALS

The dinosaurs were the subphylum of chordates, specifically, "those with backbones or spinal columns that conquered the terrestrial ecosystem for over 160 million years” (5). They are a group of diapsids reptiles. They evolved “from archosauriform ancestor during the olenekian, like modern crocodilians” (5). They were seen 230 million years ago, and disappeared 65 million years back. The clade maniraptoran is the “group of the theropod dinosaurs that many paleontogists believe birds were derived from some 150 million years or so ago in Jurassic period on the other side the phylogenetic taxonomy birds are by definition maniraptoran and other maniraptoran are their closest relatives” (5).


There was an argument among the scientists about the dinosaurs being warm blooded animals. Some of the palaeontologists believed that they were the warm – blooded animals just “like the modern birds and mammals are” (4). Other scientists believed that they were cold – blooded. They just imagined other cold blooded animals related to the dinosaurs and they concluded that they were also cold blooded animals, example of cold blooded animals closely related to them are the reptiles. And other scientist were neutral (4).


By saying that the dinosaurs were warm blooded animals, they meant that they were able to “adjust their body temperature internally instead of relying on their environment” (3). As far as (fact monster, 2005) is concern, the cold blooded animals depend on the temperature from the environment. They need the environment to regulate their temperature so that they can become warm (3). It seems as if there is only one way that the cold blooded animals can become warm, “basking at the sun” (3). I believe these types of animal hate winter at all, because during winter it is very cold. However the sun is available it is still cold and the day is very short while the night is long. In most cases it is cold at night.


The dinosaurs seem to be different from other group of reptiles, they had unique metabolism. The heart of the dinosaurs was found with about four “chambers which is more than other warm blooded mammals. Most of the reptiles were found with three chambers in their hearts. The cold – blood animals are having three chambers in their heart” (2). The are differences between the cold and warm blooded animals. The cold – blooded animal seems not to be growing quickly as compared to the warm – blooded animals. “More evidence was found from the dinosaur’s bones, the bones are found to be rich in the passage ways called Halversian canals which acts as transportation for nutrient – laden blood to the cells that lay down new bone” (5). This evidence was confirmed from the fast – growing bones of warm blooded mammals. “The results were the same; the warm blooded mammals had the same high density of Halversian canals” (5).


The dinosaurs became so “plentiful and abundant for a long time because they were warm – blooded animals. All the large predators available on earth today are warm blooded, except for crocodiles that occupy only one very specific area, which is water” (5).


In conclusion, the dinosaurs were the warm – blooded animals, they were very active, moving at very high speeds and they were able to hunt at any time of the day and in any season unlike the cold – blooded animals which were unable to survive the cold conditions (5).


References:


1. [http://www.priweb.org/ed/ICTHO4papers/13.htm, accessed on 11/05/2006, 13:00].

2. Science news, (2000) Telltale Dino Heart Hints at Warm Blood, [http://www.sciencenews.org/articles/20000422/fob1.asp, accessed on 11/05/2006, 13:11].

3. Fact monster (2000).Were dinosaurs warm-blooded? [http://www.factmonster.com/ipka/A0862622.html, accessed on 10/05/2006, 10:00].

4. [http://pubs.usgs.gov/gip/dinosaurs/warmblood.html, accessed on 10/05/2006, 11:00].

5. Wikipedia contributors. Dinosaurs. [Internet]. Wikipedia. The Free Encyclopedia; 2006 May 10, 11:16. UTC [cited 2006 May 3]. Available from: http://en.wikipedia.org/wiki/Dinosaurs.


Ms Evelyn Maleka
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