TPO 34

Both the reading and the listening sections are discussing the extinction of sea cow once lived in waters around Baring island off the coast of Siberia. The author of the reading passage argues that there are several theories about the main cause of the extinction. The lecturer, however, challenges the claim made by the author. He is of the opinion that there are problems with each of the theories.

Firstly, the article argues that, sea cows may have been overhunted by groups of native Siberian people. This argument is challenged by the professor. More specifically, he claims that sea cows were massive creatures, up to nine meters long and could weight over ten tons. He expands on the topic by bringing up the point that couple of sea cows could feed Siberians for month. Moreover, the population of the native Siberian people was not very large, they certainly did hunt the sea cows, but they did not need hunt a lot of them.

Secondly, the text suggests that sea cows may have been extinct in the result of ecosystem disturbance that caused a decline in kelp population, which was their main source of food. The lecturer, by contrast, rebuts this argument by mentioning that eco system disturbance would not just affect only kelp but also other parts of the eco system. In addition to this he mentions that there would be decline in other marine species such as whales, but there was no decline in whales’ population. Since there was no indication of broader problems in eco system, kelp was likely growing fine and sea cows did not experience food shortage.

Finally, the reading passage notes that sea cows may have been extinct because of European fur traders, that were hunting sea cows. The lecturer, rebuts this by mentioning that it might seem like European traders were responsible, but by the time they arrived sea cow population was already quite small. Scientists indicate that sea cow was at its largest one hundred of years before the European traders arrived. He elaborates on this by bringing up the point that something was causing serious decrease in sea cow population long before the Europeans arrived, whatever it was, it should be considered as a main purpose of sea cow's extinction.