Integrated essay for TOEFL
Reading
The sea otter is a small mammal that lives in waters along the western coast of North America from California to Alaska. When some sea otter populations off the Alaskan coast started rapidly declining a few years ago, it caused much concern because sea otters play an important ecological role in the coastal ecosystem. Experts started investigating the cause of the decline and quickly realized that there were two possible explanations: environmental pollution or attacks by predators. Initially, the pollution hypothesis seemed the more likely of the two.
The first reason why pollution seemed the more likely cause was that there were known sources of it along the Alaskan coast, such as oil rigs and other sources of industrial chemical pollution. Water samples from the area revealed increased levels of chemicals that could decrease the otters’ resistance to life-threatening infections and thus could indirectly cause their deaths.
Second, other sea mammals such as seals and sea lions along the Alaskan coast were also declining, indicating that whatever had endangered the otters was affecting other sea mammals as well. This fact again pointed to environmental pollution, since it usually affects the entire ecosystem rather than a single species. Only widely occurring predators, such as the orca (a large predatory whale), could have the same effect, but orcas prefer to hunt much larger prey, such as other whales.
Third, scientists believed that the pollution hypothesis could also explain the uneven pattern of otter decline: at some Alaskan locations the otter populations declined greatly, while at others they remained stable. Some experts explained these observations by suggesting that ocean currents or other environmental factors may have created uneven concentrations of pollutants along the coast.
Listening
Professor:
Well, ongoing investigations have revealed that predation is the most likely cause of sea otter decline after all. Well, ongoing investigations have revealed that predation is the most likely cause of sea otter decline after all.
First, the pollution theory is weakened by the fact that no one can really find any dead sea others washing off on Alaskan beaches. That’s not what you would expect if infections caused by pollution started killing a lot of otters. On the other hand, the fact that it’s so hard to find dead otters is consistent with the predator hypothesis. If an otter is killed by a predator, it’s eaten immediately so it can’t wash up on shore.
Second, although orcas may prefer to hunt whales, whales have essentially disappeared from the area because of human hunters. That means that orcas have had to change their diet to survive and since only smaller sea mammals are now available, orcas have probably started hunting those. So it probably is the orcas that are causing the decline of all the smaller sea mammals mentioned in the passage – the seals, the sea lions and the sea otters.
And third, the uneven pattern of otter decline is better explained by the orca predation theory than by the pollution theory. What happens to otters seems to depend on whether the location where they live is accessible to orcas or not. In those locations that orcas can access easily, the number of sea otters has declined greatly. However, because orcas are so large, they can’t access shallow or rocky locations. And shallow and rocky locations are precisely the types of locations where sea otter populations have not declined.
The reading and the listening share the same topic about reducing in population of sea otters. The author believes that the pollution in that area is the main cause, while the professor disagrees with the claim made in lecture and she believes that the main cause of reduction in sea otters population is because of predators.
To begin with, the author contends that there were pollution sources along the Alaska coast so the main cause of reduction is pollution. This runs against the professor idea that if the main cause of declining in population of otters is pollution, there should be dead sea otters washed into coast but no one find any. She explains that the fact of not finding any dead sea otter act as a reason that predators are the main cause of population reduction because they immediately eat their pray so no one can find any dead body.
Secondly, the reading asserts that there is a reduction in population of some other types of sea mammals too which can be caused by pollution rather than hunting because it affects the whole ecosystem rather than one type of mammal. This argument is rebutted by the lecturer. She explains, in fact orcas are the main reason of reduction in population of different types of sea mammals. She elaborates on this by mentioning that orcas are forced to hunt smaller sea mammals because of human whale hunting that reduces orcas main source food.
As a final point, in contrast to the passage's claim that pollution is the main cause because of uneven pattern of reduction in population, the professor reminds students that this uneven pattern can be better explained by orca theory because reduction in population happens in areas that are accessible for orcas. But in location such as rocky and shallow waters there is no reduction in population of sea otters because these locations are not readily accessible to orcas.
Grammar and spelling errors:
Line 1, column 285, Rule ID: POSSESIVE_APOSTROPHE[1]
Message: Possible typo: apostrophe is missing. Did you mean 'otters'' or 'otter's'?
Suggestion: otters'; otter's
...that the main cause of reduction in sea otters population is because of predators. To...
^^^^^^
Discourse Markers used:
['but', 'if', 'second', 'secondly', 'so', 'while', 'in contrast', 'in fact', 'such as', 'in contrast to', 'to begin with']
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance in Part of Speech:
Nouns: 0.30029154519 0.261695866417 115% => OK
Verbs: 0.134110787172 0.158904122519 84% => OK
Adjectives: 0.0728862973761 0.0723426182421 101% => OK
Adverbs: 0.0291545189504 0.0435111971325 67% => OK
Pronouns: 0.0204081632653 0.0277247811725 74% => OK
Prepositions: 0.204081632653 0.128828473217 158% => OK
Participles: 0.0291545189504 0.0370669169778 79% => OK
Conjunctions: 2.53831194551 2.5805825403 98% => OK
Infinitives: 0.0116618075802 0.0208969081088 56% => OK
Particles: 0.0 0.00154638098197 0% => More particles wanted.
Determiners: 0.113702623907 0.128158765124 89% => OK
Modal_auxiliary: 0.0116618075802 0.0158828679856 73% => OK
WH_determiners: 0.00874635568513 0.0114777025283 76% => OK
Vocabulary words and sentences:
No of characters: 1880.0 1645.83664459 114% => OK
No of words: 321.0 271.125827815 118% => OK
Chars per words: 5.85669781931 6.08160592843 96% => OK
Fourth root words length: 4.23278547379 4.04852973271 105% => OK
words length more than 5 chars: 0.339563862928 0.374372842146 91% => OK
words length more than 6 chars: 0.261682242991 0.287516216867 91% => OK
words length more than 7 chars: 0.171339563863 0.187439937562 91% => OK
words length more than 8 chars: 0.13707165109 0.113142543107 121% => OK
Word Length SD: 2.53831194551 2.5805825403 98% => OK
Unique words: 146.0 145.348785872 100% => OK
Unique words percentage: 0.454828660436 0.539623497131 84% => OK
Word variations: 45.1040556082 53.8517498576 84% => OK
How many sentences: 11.0 13.0529801325 84% => OK
Sentence length: 29.1818181818 21.7502111507 134% => OK
Sentence length SD: 73.0530204827 49.3711431718 148% => OK
Chars per sentence: 170.909090909 132.220823453 129% => OK
Words per sentence: 29.1818181818 21.7502111507 134% => OK
Discourse Markers: 1.0 0.878197800319 114% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 3.39072847682 29% => OK
Readability: 55.3500424809 50.5018328374 110% => OK
Elegance: 2.90476190476 1.90840788429 152% => OK
Coherence and Cohesion:
Essay topic to essay body coherence: 0.308955416975 0.451937469235 68% => OK
Sentence sentence coherence: 0.228796583114 0.142949733639 160% => OK
Sentence sentence coherence SD: 0.109117968648 0.0787303798458 139% => OK
Sentence paragraph coherence: 0.688426016306 0.631733273073 109% => OK
Sentence paragraph coherence SD: 0.165833109644 0.139662658121 119% => OK
Sentence topic coherence: 0.165981050609 0.21790590567 76% => OK
Sentence topic coherence SD: 0.0481451514008 0.0871468918476 55% => OK
Paragraph paragraph coherence: 0.486525098871 0.414875509568 117% => OK
Paragraph paragraph coherence SD: 0.0568741371302 0.0530846634433 107% => OK
Paragraph topic coherence: 0.228621078528 0.332364718235 69% => OK
Paragraph topic coherence SD: 0.0312977949589 0.0446026805963 70% => OK
Task Achievement:
Sentences with positive sentiment : 3.0 4.33554083885 69% => OK
Sentences with negative sentiment : 5.0 4.45695364238 112% => OK
Sentences with neutral sentiment: 3.0 4.26048565121 70% => OK
Positive topic words: 3.0 3.49668874172 86% => OK
Negative topic words: 4.0 3.62251655629 110% => OK
Neutral topic words: 3.0 3.1766004415 94% => OK
Total topic words: 10.0 10.2958057395 97% => OK
---------------------
Rates: 86.6666666667 out of 100
Scores by essay e-grader: 26.0 Out of 30
---------------------
Note: the e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations to cover all aspects.