TPO 42 Integrated Writing Task

Both the passage and the lecture discuss the extinction of Steller's sea cows, which once lived near the Siberian coast. The reading suggests three theories for this phenomenon. On the other hand, the professor states that those theories have problems and opposes each one.
First, the passage states that since sea cows were good sources for food in severe environments, overhunting by groups of native Siberian people was the cause of this extinction. Nevertheless, the professor rejects the author's view and illustrates that sea cows were massive creatures, nine meters long, and weighed around ten tons. A couple of sea cows would feed a village of native people for a long time, so natives did not have to hunt many of them.
Second, the reading claims that disturbances in the ecosystem caused the decline in sea cows' primary food source, kelp. Nonetheless, the lecturer denies this idea and states that it would affect other parts of the ecosystem if something severe had happened. He explains that in such a situation, other marine animals like whales would be extinct. Since there no indication of the extinction of other creatures, it is unlikely that climate change would be responsible for sea cow extinction.
Finally, the author mentions that European fur traders who came to the island after 1741 were mainly responsible for this extinction because they hunted the last sea cow. However, the speaker refutes it, saying that before the arrival of European fur traders, the population of sea cows was already very low. He states that something had happened a few hundred years before those traders came to the island, which was the main reason for extinction.