Summarize the point made in the lecture ， being sure to explain how the cast doubt on specific points made in the reading passage.

The article states that dinosaurs were endotherm and provides three reasons of support. However, the speaker explains that there are not enough proves to support the fact that dinosaurs are endotherm and refutes each of the author's reasons.

First, the reading claims that dinosaur's fossils have been found in polar region and only endotherm animals could have survived to this cold climate. The professor refutes this point by saying that the Polar Regions in that time were warmer than today. He states that although temperatures were extremely cold, dinosaurs could have been migrated or hibernated to other warmer areas. Thus, the discovery of dinosaur's fossil does not prove they were actually endotherm.

Second, the article posits that leg underneath is one reason to believe dinosaurs were endotherm. Moreover the author points out that leg under body allowed them to perform physical activity, such as running. However, the professor says that the position of the legs has another good explanation. Therefore, the legs enabled dinosaurs to support their weight because of the large size. According to the professor, this is one reason why dinosaurs had the legs underneath, so they were not endotherm.

Finally, the article says that dinosaurs had bone’s structures called harvesian canals, which are presented exclusively in endotherms. In addition, the author states that these structures caused continue growing in endothermic animals and this is one feature of animals that are endotherm. The professor opposes to this point by explaining that although Harvesian canals were found in dinosaurs, they had also growth rings, which allowed dinosaurs to have interrupted growing, and thus, this is a characteristic of non endotherm animals.