Sea otters are a small mammal that lives in the waters along North America's west coast from California to Alaska. A few years ago some of the sea otter populations off the Alaskan coast started to decline rapidly, which raised several concerns because of their important role in the coastal ecosystem. Experts began investigating and came up with two possible explanations. One explanation was environmental pollution and the second was attacks by predators. It seems clear that it was, in fact, environmental pollution that was the cause.
One reason pollution was more likely was because of the known pollution sources along the Alaskan coast such as oil rigs. Also water samples taken in the area showed increased levels of chemicals that could decrease the otters' immune systems and indirectly result in their deaths.
Another thing that pointed to pollution as the culprit was the decline of other sea mammals such as seals in the same areas. This indicated that whatever was affecting the otters was also affecting the other sea mammals. Environmental pollution usually affects an entire ecosystem instead of just one species. Only predators that occurred in a large area, such as orcas (a large predatory whale), could cause the same effect, but they usually hunt larger prey.
Finally, scientists believed the pollution hypothesis would also explain the uneven pattern of otter decline. In some Alaskan locations the otter population declined greatly while other populations remained stable. Some experts suggested this could be explained by the fact that ocean currents, or other environmental factors, might have created uneven concentrations of pollutants along the coast.
Question:
Summarize the points made in the lecture and explain how the speaker casts doubt on specific points made in the reading passage.
The reading passage and the lecture are both about the sea otter population decline. The lecturer completely refutes the arguments in the article. She argues that these explanations are faulty.
Firstly, the lecture states that predation is the most plausible cause for the decline in otter population instead of pollution because no one dead otter can be found on the Alaska beaches. Therefore, if an infection caused by pollution was the cause a lot of dead animals could be seen. It is hard to find dead otters because of the predation. This directly opposes the reading passage that states that an increase in levels of chemicals could cause a decrease in otter’s defense to infections which indirectly provoke their deaths.
Secondly, the lecturer explains that although orcas prefer to hunt whales they are disappearing because of human hunters. As a result, orcas change their eating habits and start to eat sea otters, lions and seals. This idea disagrees with the article that claims that environmental pollution explains better this decline in a wide variety of species.
Finally, the lecturer believes that the uneven pattern of otter decline in some locations are related to the orcas’ access or not to these locations. Orcas can not enter in shallow or rocky locations that are the precise locations where otters population remains stable. The reading passage, on the other hand, argues that ocean currents or other environmental factors created these uneven pattern of reduction in otter’s population.
Transition Words or Phrases used:
finally, first, firstly, if, second, secondly, so, therefore, as a result, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 10.0 10.4613686534 96% => OK
Auxiliary verbs: 4.0 5.04856512141 79% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 12.0 12.0772626932 99% => OK
Pronoun: 21.0 22.412803532 94% => OK
Preposition: 27.0 30.3222958057 89% => OK
Nominalization: 11.0 5.01324503311 219% => Less nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1298.0 1373.03311258 95% => OK
No of words: 244.0 270.72406181 90% => More content wanted.
Chars per words: 5.31967213115 5.08290768461 105% => OK
Fourth root words length: 3.95227774224 4.04702891845 98% => OK
Word Length SD: 2.67901155827 2.5805825403 104% => OK
Unique words: 138.0 145.348785872 95% => More unique words wanted.
Unique words percentage: 0.565573770492 0.540411800872 105% => OK
syllable_count: 409.5 419.366225166 98% => OK
avg_syllables_per_word: 1.7 1.55342163355 109% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 4.0 3.25607064018 123% => OK
Article: 6.0 8.23620309051 73% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 1.0 2.5761589404 39% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 18.0 21.2450331126 85% => The Avg. Sentence Length is relatively short.
Sentence length SD: 47.4546186203 49.2860985944 96% => OK
Chars per sentence: 99.8461538462 110.228320801 91% => OK
Words per sentence: 18.7692307692 21.698381199 87% => OK
Discourse Markers: 7.07692307692 7.06452816374 100% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 4.0 4.33554083885 92% => OK
Sentences with negative sentiment : 5.0 4.45695364238 112% => OK
Sentences with neutral sentiment: 4.0 4.27373068433 94% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.150689984163 0.272083759551 55% => OK
Sentence topic coherence: 0.0536234894953 0.0996497079465 54% => OK
Sentence topic coherence SD: 0.0490752612049 0.0662205650399 74% => OK
Paragraph topic coherence: 0.0864950586045 0.162205337803 53% => OK
Paragraph topic coherence SD: 0.0215919884057 0.0443174109184 49% => Paragraphs are similar to each other. Some content may get duplicated or it is not exactly right on the topic.
Essay readability:
automated_readability_index: 13.0 13.3589403974 97% => OK
flesch_reading_ease: 44.75 53.8541721854 83% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 11.5 11.0289183223 104% => OK
coleman_liau_index: 13.58 12.2367328918 111% => OK
dale_chall_readability_score: 9.38 8.42419426049 111% => OK
difficult_words: 75.0 63.6247240618 118% => OK
linsear_write_formula: 6.5 10.7273730684 61% => OK
gunning_fog: 9.2 10.498013245 88% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
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Rates: 80.0 out of 100
Scores by essay e-grader: 24.0 Out of 30
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Note: the e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations by advanced module of e-grader and human graders.