The reading and the lecture are both about the reasoning behind decreasing the sea otter population. More specifically, in regard to the passage, the author presents three theories that supports the environmental pollution or predators are the main causes of that.
The lecturer disputes the claims made in the article, He points out that predation is the most likely causes this decline.
First and foremost, the author of the reading states pollution of many kinds of pollutants like gas and industries garbage can caused this decrease. The article mentions that these materials can decrease these animals resistance and can affect them. This argument is challenged by the lecturer. He claims that this claim is weaken because no dead animals on the beaches . Additionally, he points out that otters can not wash up or shore.
Secondly, the author suggests that because there are many animals population decreased like seals, that is related to the otter mammal .In the article it is said that this supported the theory about the pollution. Again, the speaker specifically addresses this point when he states whales decreased because the human hunting. He goes on to say that after disappearing of whales, they started to hunt small mammals like seals and otters.
Finally, the author brings his argument to a close by suggesting that unusual pattern of otter attributed to the pollution hypothesis because this decrease is differ from place to place. Not surprisingly, the lecturer takes issue with this claim by contending that uneven pattern is best explained by orca theory that pollution theory because orca so large, so the do not have the access to go to shallow or rocky locations.