The reading passage examines the top that, environment pollutions, ratherthan attacks by predators are more likely the reasons for the declining of seaotter populations. The professor’s speech concerns with the same topic.However, she contends that environment pollution is more likely the explanationfor the decreased otters, which is the opposite of what the reading passagesays. And in the presentation, she offers lots of evidence to buttress heridea.
First, even though the reading passage indicates that water samplescontain increased levels of chemical, which directly lead to the otters deathsfor the reason that otters can't fight against infections that threaten theirlife. The professor argues in the lecture that the pollution hypothesis will beweakened because no one can find death otters washing up on the Alaska beaches. That isnot what we expect if pollutions give otters life-threatening infections. Thefact that we can hardly find death otters prove the predator hypothesis.
Second, the reading passage states that pollutions have negative effectsnot only on the otter, but also on other sea mammals. However, the lecturersays that because human has preyed so much whales that the orcas have to changetheir diets. Consequently, all the small sea mammals, including the sea lionsand seals, are available for orcas.
Third, the professor believes that the amount of otters depends on thelocation they live while the reading passage claims the uneven pattern of otterdecline. The professor gives us details that otters living in the place whereorcas can access easily decline greatly and ones in the place where orcas cantget into do not decrease. She also points out the fact that orca is too largeto get in to shallow and rocky areas to support her idea.
To sum up, the professor precisely finds the flaws in the reading passage,and compelling proves that environment pollutions instead of the predatorscause the decline of sea otters in Alaska . |