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 of the Alaskan coast started to decline rapidly and 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.
At first it seemed as if the pollution was the most likely cause for the population decline. 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 ocean currents, or other environmental factor, might have created uneven concentrations of pollutants along the coast.
The debate is about the rapid decline in the sea otter population from the coastline starting from Alaska to California. As per the passage the rapid decline in sea otter population is said to be due to increase in levels of pollution at some places. This is reinforced by the fact that testing the water at these places yielded results which suggested excessive presence of chemicals in the water due to the presence of oil rigs. However, as per the lecture the hypothesis that the rapid decline in the sea otter population is due to pollution is challenged. As per the lecture, the main hypothesis for rapid sea otter decline is due to predation. The evidence given for the hypothesis are as below.
Firstly, as per the lecture it is stated that, if there was decline in sea otter population due to pollution, then the carcass of sea otters would have been found lying alongside the shore line. However, this is not the case. Very few carcasses of sea otters are found lying in the shore, thereby suggesting that these sea otters are being eaten by their predators.
Secondly, it is stated that there is a strong decline in the population of whales in these areas. Thus, orcas are forced to feed upon sea otters and other species of sea animals because of survival. Moreover, the uneven decline in sea otter population is due to the uneven distribution of orcas. Thus, areas, where the density of sea orcas are higher, there is larger predation on sea otters, thereby a larger decline in these areas. In order to strengthen the above stated argument, it is also stated that the population of sea otters is stable in shallow waters, where there are no orcas present to predate them. Thus, the above arguments strengthen the hypothesis that the decline of sea otters is due to predation rather than pollution.
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Grammar and spelling errors:
Line 1, column 122, Rule ID: SENTENCE_FRAGMENT[1]
Message: “As” at the beginning of a sentence requires a 2nd clause. Maybe a comma, question or exclamation mark is missing, or the sentence is incomplete and should be joined with the following sentence.
...ine starting from Alaska to California. As per the passage the rapid decline in se...
^^
Discourse Markers used:
['also', 'but', 'first', 'firstly', 'however', 'if', 'moreover', 'second', 'secondly', 'so', 'then', 'thus']
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance in Part of Speech:
Nouns: 0.284482758621 0.261695866417 109% => OK
Verbs: 0.14367816092 0.158904122519 90% => OK
Adjectives: 0.0747126436782 0.0723426182421 103% => OK
Adverbs: 0.0431034482759 0.0435111971325 99% => OK
Pronouns: 0.0172413793103 0.0277247811725 62% => OK
Prepositions: 0.163793103448 0.128828473217 127% => OK
Participles: 0.0488505747126 0.0370669169778 132% => OK
Conjunctions: 2.50789492068 2.5805825403 97% => OK
Infinitives: 0.0344827586207 0.0208969081088 165% => OK
Particles: 0.0 0.00154638098197 0% => OK
Determiners: 0.120689655172 0.128158765124 94% => OK
Modal_auxiliary: 0.00287356321839 0.0158828679856 18% => OK
WH_determiners: 0.00862068965517 0.0114777025283 75% => OK
Vocabulary words and sentences:
No of characters: 1815.0 1645.83664459 110% => OK
No of words: 316.0 271.125827815 117% => OK
Chars per words: 5.74367088608 6.08160592843 94% => OK
Fourth root words length: 4.21620550194 4.04852973271 104% => OK
words length more than 5 chars: 0.329113924051 0.374372842146 88% => OK
words length more than 6 chars: 0.237341772152 0.287516216867 83% => OK
words length more than 7 chars: 0.145569620253 0.187439937562 78% => OK
words length more than 8 chars: 0.117088607595 0.113142543107 103% => OK
Word Length SD: 2.50789492068 2.5805825403 97% => OK
Unique words: 134.0 145.348785872 92% => OK
Unique words percentage: 0.424050632911 0.539623497131 79% => More unique words wanted or less content wanted.
Word variations: 41.4270292903 53.8517498576 77% => OK
How many sentences: 15.0 13.0529801325 115% => OK
Sentence length: 21.0666666667 21.7502111507 97% => OK
Sentence length SD: 43.8096894407 49.3711431718 89% => OK
Chars per sentence: 121.0 132.220823453 92% => OK
Words per sentence: 21.0666666667 21.7502111507 97% => OK
Discourse Markers: 0.8 0.878197800319 91% => OK
Paragraphs: 3.0 4.09492273731 73% => OK
Language errors: 1.0 3.39072847682 29% => OK
Readability: 44.8008438819 50.5018328374 89% => OK
Elegance: 2.43661971831 1.90840788429 128% => OK
Coherence and Cohesion:
Essay topic to essay body coherence: 0.455939549514 0.549887131256 83% => OK
Sentence sentence coherence: 0.199298598319 0.142949733639 139% => OK
Sentence sentence coherence SD: 0.151317676058 0.0787303798458 192% => Ideas in sentences are similar.
Sentence paragraph coherence: 0.649833358453 0.631733273073 103% => OK
Sentence paragraph coherence SD: 0.139687038476 0.139662658121 100% => OK
Sentence topic coherence: 0.249157279678 0.266732575781 93% => OK
Sentence topic coherence SD: 0.0700879133996 0.103435571967 68% => OK
Paragraph paragraph coherence: 0.538951189661 0.414875509568 130% => OK
Paragraph paragraph coherence SD: 0.0173922931183 0.0530846634433 33% => OK
Paragraph topic coherence: 0.374275283436 0.40443939384 93% => OK
Paragraph topic coherence SD: 0.0219053286345 0.0528353158467 41% => The ideas may be duplicated in paragraphs.
Task Achievement:
Sentences with positive sentiment : 2.0 4.33554083885 46% => OK
Sentences with negative sentiment : 6.0 4.45695364238 135% => OK
Sentences with neutral sentiment: 7.0 4.26048565121 164% => OK
Positive topic words: 2.0 3.49668874172 57% => OK
Negative topic words: 6.0 3.62251655629 166% => OK
Neutral topic words: 4.0 3.1766004415 126% => OK
Total topic words: 12.0 10.2958057395 117% => OK
What are sentences with positive/Negative/neutral sentiment?
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Not in a correct format.
The correct pattern:
para 1: introduction
para 2: doubt 1
para 3: doubt 2
para 4: doubt 3
Less contents wanted from the reading passages(25%) but more content wanted from the lecture (75%).
Don't need a conclusion paragraph.
Read sample essays from ETS:
http://www.testbig.com/users/toeflwritingmaster
Rates: 70.0 out of 100
Scores by essay e-grader: 21.0 Out of 30
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Note: This is not the final score. 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.