TPO 10 Integrated Writing Task

The article and the lecture both discuss the probable reason of declining in the otter population along the north-west coastline of North America. While the lecture enumerates environmental pollution as the main cause for this phenomenon, the professor believes that predation of otter by large whale specifically orca is the main reason of this decline.
First, the reading material claims the main source of oil rigs and industrial chemical pollutants in this area caused this declining of population because the increasing of concentration of water pollutants decrease resistance of not only otter but also other mammals to infection diseases which lead to their death. On the other hand, the lecturer challenges this opinion by explaining that there is no washed out the otter. She adds that if infection is the reason of otters’ death, we should see the remaining of its body. But predator can kill them and washed out of them.
Second, the author asserts that population of not only otter but also other mammal such as lions and seals have decreased as a sign of environmental disaster in that area which affected the entire ecosystem. However, the professor rebuts this argue and mentions that whales are disappeared by human hunting. Then, orca has become the main predator of the otter. It has changed its eating habit from other whales to otter. Hence, the otter population decreased a lot in recent years.
Third, the writer of the article posits that the uneven and dispersed population of the otter could be explained better with the environmental theory. The scientists consider the different concentration of pollutants as the reason of this declining pattern. Conversely, the speaker repudiates this idea by saying that uneven population of otter could be explained better by the predation hypothesis. Since, the orca could not access some shallow and rocky section of the coastline the otter which live in these areas are safer and live in a larger group.