Endotherms are animals such as modern birds and mammals that keep their body temperatures constant For instance humans are endotherms and maintain an internal temperature of 37 C no matter whether the environment is warm or cold Because dinosaurs were

The reading and lecture are about whether dinosaurs were endotherms or not. The author of the reading believes that in spit dinosaurs were reptiles, but there is evidence that they were endotherms. However, the lecturer finds all the ideas dubious and presents some evidence to refute them all. She thinks that dinosaurs were not endotherms.

First of all the author argues that polar dinosaurs' fossil shows us, they could maintain their internal temperature because they lived in a cold climate. Conversely, the lecturer brings up the idea that in that time the polar region was so warmer than today or maybe they migrated to the polar region.

Secondly, the reading passage holds the view that running ability is one of the endotherms animals feathers, and running is just available when animals have legs which position of them are underneath of their body, so dinosaurs have this type of body structures. On the contrary, the professor underlines the fact that the positions of dinosaurs legs have many other reasons such as weight means that they need these positions of legs to be able to bear their weight.

Finally, the reading asserts that Haversian canals are usually in the bone structure of endotherms. This feature of structure helps much to grow faster and growing fast is a characteristic of endotherms. It is noted that it is oblivious in dinosaurs fossils Haversian canals exist. The lecturer casts doubt on this by arguing that the dinosaurs were not growing fast in all periods of their living time in fact in a cool period they grow slower than other periods. This evidence implies that they were not endotherms.