Both the reading passage and lecture discuss whether dinosaurs were endotherm or not. The former argues that they were endotherm for three reasons. But the latter contradicts each of these points.
To begin with, the author of the passage claims that the dinosaurs were endotherm because they lived in polar regions. However, the lecturer contends that the polar areas were warmer in the past. In addition to this, maybe the dinosaurs migrated to relatively warm areas in cold seasons.
Second of all, the text asserts that legs of dinosaurs were underneath their bodies. Thus, they could be assumed as endotherms. In contrast, the listening counters that the main reason for this structure was to support more weight. Large size was one of the advantages of dinosaurs.
Finally, the author brings his argument to a close by suggesting that the existence of Hoversian canals supports the idea that these animals were endotherm. Again, the speaker specifically addresses this point and states that she agrees that they have these canals. Nonetheless, they followed a pattern of periodic growth. They grew slowly during the cold periods. That is not a characteristic of endotherm animals, because they grow rapidly in spite of the temperature of environment.
To sum up, it is clear that both the writer and professor hold conflicting views about whether dinosaurs have such a characteristic or not.