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.
Both the passage and the lecture discuss about the cause of decline in the sea otter. The passage claims that the pollution hypothesis is more likely the explanation for the phenomenon. However, the lecture disputes that the predation hypothesis is the more probable explanation for it.
First of all, the passage argues that there were known sources of pollution along the Alaskan coast. Which leads to decrease of the sea otter population. In contract, the lecture denies the passage by citing the evidence that there are no dead otter body found on the beach. And suggests that when the predators prey on sea otters, they consume the body as well.
Furthermore, the passage claims that though orcas are the predator prey on sea otters, they prefer to hunt larger prey like whales. On the other hand, the lecture argues that orcas are the likely factor in the disappearance of sea otters. Because of the scarcity of whales, orcas turned to prey on sea otters.
Finally, the passage suggests that the pollution hypothesis is able to explain the uneven pattern of otter decline. However, the lecture states that the uneven pattern of otter decline depends on the accessibility to sea otters for orcas. Since the area that orcas are prevalent usually has smaller population the sea otters.
Grammar and spelling errors:
Line 3, column 102, Rule ID: SENTENCE_FRAGMENT[1]
Message: “Which” 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.
...s of pollution along the Alaskan coast. Which leads to decrease of the sea otter popu...
^^^^^
Line 7, column 240, Rule ID: SENTENCE_FRAGMENT[1]
Message: “Since” 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.
... accessibility to sea otters for orcas. Since the area that orcas are prevalent usual...
^^^^^
Transition Words or Phrases used:
finally, first, furthermore, however, so, well, first of all, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 8.0 10.4613686534 76% => OK
Auxiliary verbs: 0.0 5.04856512141 0% => OK
Conjunction : 2.0 7.30242825607 27% => More conjunction wanted.
Relative clauses : 12.0 12.0772626932 99% => OK
Pronoun: 13.0 22.412803532 58% => OK
Preposition: 28.0 30.3222958057 92% => OK
Nominalization: 10.0 5.01324503311 199% => OK
Performance on vocabulary words:
No of characters: 1084.0 1373.03311258 79% => OK
No of words: 216.0 270.72406181 80% => More content wanted.
Chars per words: 5.01851851852 5.08290768461 99% => OK
Fourth root words length: 3.83365862548 4.04702891845 95% => OK
Word Length SD: 2.4452685199 2.5805825403 95% => OK
Unique words: 101.0 145.348785872 69% => More unique words wanted.
Unique words percentage: 0.467592592593 0.540411800872 87% => More unique words wanted or less content wanted.
syllable_count: 344.7 419.366225166 82% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 8.0 8.23620309051 97% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 16.0 21.2450331126 75% => The Avg. Sentence Length is relatively short.
Sentence length SD: 21.2039964973 49.2860985944 43% => The essay contains lots of sentences with the similar length. More sentence varieties wanted.
Chars per sentence: 83.3846153846 110.228320801 76% => OK
Words per sentence: 16.6153846154 21.698381199 77% => OK
Discourse Markers: 6.07692307692 7.06452816374 86% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 2.0 4.19205298013 48% => 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: 7.0 4.27373068433 164% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.232071657715 0.272083759551 85% => OK
Sentence topic coherence: 0.0980441725409 0.0996497079465 98% => OK
Sentence topic coherence SD: 0.0672309586025 0.0662205650399 102% => OK
Paragraph topic coherence: 0.149034914407 0.162205337803 92% => OK
Paragraph topic coherence SD: 0.0482950232261 0.0443174109184 109% => OK
Essay readability:
automated_readability_index: 10.5 13.3589403974 79% => Automated_readability_index is low.
flesch_reading_ease: 55.24 53.8541721854 103% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 9.5 11.0289183223 86% => OK
coleman_liau_index: 11.54 12.2367328918 94% => OK
dale_chall_readability_score: 8.38 8.42419426049 99% => OK
difficult_words: 54.0 63.6247240618 85% => More difficult words wanted.
linsear_write_formula: 7.0 10.7273730684 65% => OK
gunning_fog: 8.4 10.498013245 80% => OK
text_standard: 10.0 11.2008830022 89% => OK
What are above readability scores?
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Rates: 73.3333333333 out of 100
Scores by essay e-grader: 22.0 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.