The passgae and lecture are arguing over why see cows were extiniction.

The passgae and lecture are arguing over why see cows were extiniction. The reading passage author lists out three possible theories about the main cause of the extinction. On the contrary, the lecturer challenges these theorie one by one. Firstly, the passage notes that the native Siberian people might hunt these animals too much. In contrast, the professor refuese this point and he states that sea cows were large animlas with over ten tones weight and, the populations of the native people was not large. Therefore, these poeple did not need to hunt many sea cows which cuased the sea cow extinction. Secondly, the passage author mentions the ecological ecosystem as a main factor for sea cow extinction. On the other hand, the professor rebuts this reason and he asserts that ecological disturbance should effect other animals like whales besides the kelpes while fishing ships reported nothing about the whales decline. In other words, no food shoratage was ocurred for sea cows. Third, the author states that European fur traders might hunt sea cows. Nevertheless, the professor holds an opposite view and he says that the sea cow popluation had been declining for one century by European fur traders arrived. Hence, the sea cow extinction which occured only some years after European fur traders, had nothing to do with European fur traders. In a nutshell, the author mentions three theories as a main factors of the sea cow ectinction, but the lecturer objecets all of them.