TPO 10:
The lecture obviously disputes the points stated in the reading material. According to the passage, the pollution is the main cause of otters' decline. However, this statement is not regarded in the eye of the lecture.
First of all, the professor claims that though there are known sources of pollution along the Alaskan coast, no one can really find any died species. Due to this situation, it is most likely to be explained by the predator hypothesis. If the otters are killed by the predators, it is hard to find something left. So the lecture totally disagrees with the view made in the passage.
Second, the passage presents that other sea mammals are declining as well as the otters. This fact again points to the environmental pollution. But the professor mentions that because of human's hunting for the large mammals, the otters have to turn to the small mammals. So the decline of small mammal results from the change of otters' diet, not the pollution.
Finally, the professor asserts that the uneven pattern of otter decline reflects the predator hypothesis more, whereas the author of the reading thinks the uneven concentrations of pollutants by the ocean currents are the reason. The professor proves his claim by pointing out that just the location where the otters' predator can access them occur the great decline of the otters. The otters in the shallow place where their predator can't get in don't decline a lot.