The reading and lecture are both about powered flight ability of Pterosaurs. The author of reading feels that pterosaurs were not able to fly by flapping their wings. The lecturer challenges the claims made by the author. He is of opinion that these explanations are faulty.
To begin with, the author argues that pterosaurs were probaly cold-blooded similar to modern reptiles. The article mentions that powered flight ability comsuming a lot of energy, thus all modern animal that fly are warm-blooded. This specific argument is challenged by the lecturer. He claims that recent fosile reveal that reptiles have further or hair, accordingly the have high body temprature. Additionally, he said that pterosaurs didn't need a lot of energy to flight.
Secondly, the writer suggest that pterosaurs were too large and so heavy. Hence, it is difficult for them to aloft by flaping their wings. The lecturer, however, rebuts this by mentioning that pterosaurs's bones were not solid, so their weight is light enough to stay aloft.
Finally, the author points out that reptiles need big and powerful muscles to take off into the air. Incontrast, the lecturer's position is that pterosaurs used four lengs to walk and launch themselves into the air.