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.
The reading passage and lecture have conflicting opinions about what has caused the sea otter population significantly decline along the Alaskan shores. The author strongly postulates that the contamination theory plays an important role in decreasing sea otters. On the other hand, the listening adamantly delineates that invaded by predators theory is more plausible, so the writer's explanations are weak and groundless.
First and foremost, according to the author of the excerpt, seashores factories led to rapidly diminish its population because its chemicals affect adversely on their immunities and causes their deaths. Nonetheless, the professor offsets these points by declaring that according to the investigation, they didn't find any evidence of death sea otter along Alaskan offshores. Thus, the sea otters might have killed and eaten by predators.
On top of this, the professor in the lecture further asserts that the main prey of orcas, whales, have disappeared due to human activities. As a result, the orcas need to change their prey, small sea mammals, such as seals and sea otters. These claims refute the writer's implications about extinct of some species which live near the Alaskan beach can demonstrate that pollution affects the entire ecosystem. Furthermore, the author asserts that the one defect of another theory is that the only large predator, orcas, primarily prey on whales.
The article lastly insists that some ocean tidal are the environmental factor that trigger the uneven compression of pollution, so it may explain why some areas sea otter dramatically declined and others not. The speaker in the listening counters these indications by elaborating that an uneven diffusion of pollution can not fully explain it. However, some areas where orcas are accessible with sea otters exactly match with the fields where sea otters' population have significantly declined.
Grammar and spelling errors:
Line 1, column 335, Rule ID: POSSESIVE_APOSTROPHE[1]
Message: Possible typo: apostrophe is missing. Did you mean 'predators'' or 'predator's'?
Suggestion: predators'; predator's
...ng adamantly delineates that invaded by predators theory is more plausible, so the writer...
^^^^^^^^^
Line 3, column 307, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: didn't
...at according to the investigation, they didnt find any evidence of death sea otter al...
^^^^^
Line 7, column 448, Rule ID: POSSESIVE_APOSTROPHE[1]
Message: Possible typo: apostrophe is missing. Did you mean 'otters'' or 'otter's'?
Suggestion: otters'; otter's
...exactly match with the fields where sea otters population have significantly declined....
^^^^^^
Transition Words or Phrases used:
first, furthermore, however, if, lastly, may, nonetheless, so, thus, such as, as a result, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 5.0 10.4613686534 48% => More to be verbs wanted.
Auxiliary verbs: 5.0 5.04856512141 99% => OK
Conjunction : 7.0 7.30242825607 96% => OK
Relative clauses : 13.0 12.0772626932 108% => OK
Pronoun: 22.0 22.412803532 98% => OK
Preposition: 30.0 30.3222958057 99% => OK
Nominalization: 9.0 5.01324503311 180% => OK
Performance on vocabulary words:
No of characters: 1617.0 1373.03311258 118% => OK
No of words: 294.0 270.72406181 109% => OK
Chars per words: 5.5 5.08290768461 108% => OK
Fourth root words length: 4.14082457966 4.04702891845 102% => OK
Word Length SD: 2.80488531789 2.5805825403 109% => OK
Unique words: 175.0 145.348785872 120% => OK
Unique words percentage: 0.595238095238 0.540411800872 110% => OK
syllable_count: 504.0 419.366225166 120% => OK
avg_syllables_per_word: 1.7 1.55342163355 109% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 10.0 8.23620309051 121% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 3.0 2.5761589404 116% => OK
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 22.0 21.2450331126 104% => OK
Sentence length SD: 38.4636922474 49.2860985944 78% => OK
Chars per sentence: 124.384615385 110.228320801 113% => OK
Words per sentence: 22.6153846154 21.698381199 104% => OK
Discourse Markers: 8.30769230769 7.06452816374 118% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 3.0 4.19205298013 72% => OK
Sentences with positive sentiment : 2.0 4.33554083885 46% => More positive sentences wanted.
Sentences with negative sentiment : 6.0 4.45695364238 135% => OK
Sentences with neutral sentiment: 5.0 4.27373068433 117% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.276857934979 0.272083759551 102% => OK
Sentence topic coherence: 0.0945671980267 0.0996497079465 95% => OK
Sentence topic coherence SD: 0.0801087754123 0.0662205650399 121% => OK
Paragraph topic coherence: 0.164080105609 0.162205337803 101% => OK
Paragraph topic coherence SD: 0.0400658376854 0.0443174109184 90% => OK
Essay readability:
automated_readability_index: 15.8 13.3589403974 118% => OK
flesch_reading_ease: 40.69 53.8541721854 76% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 13.1 11.0289183223 119% => OK
coleman_liau_index: 14.92 12.2367328918 122% => OK
dale_chall_readability_score: 9.67 8.42419426049 115% => OK
difficult_words: 92.0 63.6247240618 145% => OK
linsear_write_formula: 12.0 10.7273730684 112% => OK
gunning_fog: 10.8 10.498013245 103% => OK
text_standard: 11.0 11.2008830022 98% => OK
What are above readability scores?
---------------------
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.