tpo34.

This set of the material in the both reading and lecture is about a massive marine animal called Steller’s sea became extinct in 1768. The reading mentions that there are threes hypotheses to clarify the reasons for extinction. On the other hand, the lecturer states that there is something wrong with all these theories and refutes all the author’s supports.

First, the passage posits that overhunting this mammal by native Siberian people to provide themselves with a reliable food source would be considered as a main factor for the extinction of this huge mammal. The speaker refutes this point by saying that this mammal weighed at least 10 tons with 9 meters that couple of them could feed a small village for some months. Therefore, native Siberian people did not need to kill a large number of them for food. As you can see, this claim is unconvincing.

Second, the reading describes that facing lack of food sources as a result of disturbing the balance of ecosystem might be another reason for the extinction. However, the professor explains that although ecological disturbance happened in 1768, this would be unreliable because this disturbance negatively affected some perts of Bering Island. For example, there was a decline in the number of whales while no reduction in fish population did not report. As a result, this phenomenon would not be such a broad problem that we can consider as a main reason of the extinction.

Third, the article claims that with the European fur trader, the population of Steller’s sea had been declined. The speaker opposes this claim by explaining that when Europen traders reached this Island, the population of this marine mamals was diminished. In fact, their population was declining since 100 years ago before these traders’s arrival.