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 passage describes in detail how sea otter population have declined due to the environmental pollution. However, the lecture refutes the theory stating that several other reasons account for the decrease in the number of sea otters.
Firstly, because of oil rigs, the immune system of sea animals decreases due to the increased level of chemicals in the water thus resulting in their death. Nevertheless, the professor points out that it is difficult to find dead sea otters on the shores since if a predator had consumed the sea otter according to the predator hypothesis, then its dead body cannot be found on seashores.
Secondly, the pollutants affect all the sea mammals since predators are found in larger area and they hunt only larger prey. This fact is contradicted by the explanation that most of the predators are hunted by humans and they could only eat small sea animals.
Thirdly, there is an uneven pattern in the decline of otter population due to the uneven concentration of pollution on water bodies. But such patterns depend on whether the location is accessible or not. if sea otters can access then there will be a great decline whereas in shallow and rocky surface, sea otters have not reduced in number.
To put in a nutshell, we can reiterate the fact that unlike scientific discoveries, other things such as predators and access to a location plays a major role in the decreasing number of sea otters.
Grammar and spelling errors:
Line 13, column 205, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: If
...ther the location is accessible or not. if sea otters can access then there will b...
^^
Transition Words or Phrases used:
but, first, firstly, however, if, nevertheless, second, secondly, so, then, third, thirdly, thus, whereas, such as
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 8.0 10.4613686534 76% => OK
Auxiliary verbs: 5.0 5.04856512141 99% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 4.0 12.0772626932 33% => More relative clauses wanted.
Pronoun: 11.0 22.412803532 49% => OK
Preposition: 34.0 30.3222958057 112% => OK
Nominalization: 8.0 5.01324503311 160% => OK
Performance on vocabulary words:
No of characters: 1207.0 1373.03311258 88% => OK
No of words: 243.0 270.72406181 90% => More content wanted.
Chars per words: 4.9670781893 5.08290768461 98% => OK
Fourth root words length: 3.94822203886 4.04702891845 98% => OK
Word Length SD: 2.67881953628 2.5805825403 104% => OK
Unique words: 141.0 145.348785872 97% => OK
Unique words percentage: 0.58024691358 0.540411800872 107% => OK
syllable_count: 374.4 419.366225166 89% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 5.0 8.23620309051 61% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 2.0 2.5761589404 78% => OK
Performance on sentences:
How many sentences: 10.0 13.0662251656 77% => Need more sentences. Double check the format of sentences, make sure there is a space between two sentences, or have enough periods. And also check the lengths of sentences, maybe they are too long.
Sentence length: 24.0 21.2450331126 113% => OK
Sentence length SD: 42.9376291847 49.2860985944 87% => OK
Chars per sentence: 120.7 110.228320801 109% => OK
Words per sentence: 24.3 21.698381199 112% => OK
Discourse Markers: 11.4 7.06452816374 161% => OK
Paragraphs: 5.0 4.09492273731 122% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 3.0 4.33554083885 69% => OK
Sentences with negative sentiment : 3.0 4.45695364238 67% => 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: 0.217812362936 0.272083759551 80% => OK
Sentence topic coherence: 0.0884265701299 0.0996497079465 89% => OK
Sentence topic coherence SD: 0.054792838265 0.0662205650399 83% => OK
Paragraph topic coherence: 0.118636519537 0.162205337803 73% => OK
Paragraph topic coherence SD: 0.0538059471199 0.0443174109184 121% => OK
Essay readability:
automated_readability_index: 14.1 13.3589403974 106% => OK
flesch_reading_ease: 55.58 53.8541721854 103% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 11.5 11.0289183223 104% => OK
coleman_liau_index: 11.84 12.2367328918 97% => OK
dale_chall_readability_score: 9.38 8.42419426049 111% => OK
difficult_words: 70.0 63.6247240618 110% => OK
linsear_write_formula: 13.5 10.7273730684 126% => OK
gunning_fog: 11.6 10.498013245 110% => OK
text_standard: 12.0 11.2008830022 107% => OK
What are above readability scores?
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Rates: 90 out of 100
Scores by essay e-grader: 27 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.