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 lifethreatening
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 passage states that, the main reason of decline in the sea otters off alaskan coast is due to environmental pollution rather than predator attacks. The passage provides three reasons to support it. However, the professor explains in the lecture that the main reason of decline in sea otters is due to predation and not due to environmental pollution and refutes each point made in the passage.
First, the passage states that there are known sources of pollution in form of oil rigs and other industrial chemical pollutions. The water samples reveal the increased level of chemicals in the ocean and hence result in decline in otter populations. The professor refutes the point by saying that no sea otters were found washed out on the alaskan beaches and they were hard to find. As the sea otters were not found along the coast it explains that they were been killed by the predators and eaten and hence cannot be seen on the alaskan beaches.
Second, the passage posits that along with sea otters other mammals like sea lions, seals were also seem to declined as environmental pollution affects entire ecosystem rather than single species. This scenario may occur due to predators such as orca but orca prefer bigger prey such as whales. The professor opposes this and says that most of the whales disappeared due to human hunting so the predators like orca has to feed on small mamals like sea otters, seal lions and seals.
Third, the passage says that in some alaskan locations the otter population greatly declined but at some locations it was stable. The scientist believed that this was due to uneven concentrations of pollutants along the coast which resulted from ocean currents or other environmental factors. The professor refutes this point and states that as orca is a large animal it cannot access shallow locations and it has been seen that the otters have not declined in the shallow regions but considerable decline is seen in the deeper regions and this suggest that the otters in the shallow locations were not hunted by orcas.
Grammar and spelling errors:
Line 4, column 101, Rule ID: BEEN_PART_AGREEMENT[2]
Message: Consider using a past participle here: 'seemed'.
Suggestion: seemed
...mammals like sea lions, seals were also seem to declined as environmental pollution ...
^^^^
Transition Words or Phrases used:
also, but, first, hence, however, may, second, so, third, as to, such as
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 16.0 10.4613686534 153% => OK
Auxiliary verbs: 3.0 5.04856512141 59% => OK
Conjunction : 16.0 7.30242825607 219% => Less conjunction wanted
Relative clauses : 13.0 12.0772626932 108% => OK
Pronoun: 24.0 22.412803532 107% => OK
Preposition: 45.0 30.3222958057 148% => OK
Nominalization: 6.0 5.01324503311 120% => OK
Performance on vocabulary words:
No of characters: 1712.0 1373.03311258 125% => OK
No of words: 349.0 270.72406181 129% => OK
Chars per words: 4.90544412607 5.08290768461 97% => OK
Fourth root words length: 4.32221490584 4.04702891845 107% => OK
Word Length SD: 2.451359314 2.5805825403 95% => OK
Unique words: 160.0 145.348785872 110% => OK
Unique words percentage: 0.458452722063 0.540411800872 85% => More unique words wanted or less content wanted.
syllable_count: 526.5 419.366225166 126% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 1.0 3.25607064018 31% => OK
Article: 12.0 8.23620309051 146% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 0.0 2.5761589404 0% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 26.0 21.2450331126 122% => The Avg. Sentence Length is relatively long.
Sentence length SD: 62.7811074737 49.2860985944 127% => OK
Chars per sentence: 131.692307692 110.228320801 119% => OK
Words per sentence: 26.8461538462 21.698381199 124% => OK
Discourse Markers: 5.53846153846 7.06452816374 78% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 5.0 4.33554083885 115% => OK
Sentences with negative sentiment : 3.0 4.45695364238 67% => 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: 0.267051367176 0.272083759551 98% => OK
Sentence topic coherence: 0.102701868421 0.0996497079465 103% => OK
Sentence topic coherence SD: 0.0709048648269 0.0662205650399 107% => OK
Paragraph topic coherence: 0.169094930719 0.162205337803 104% => OK
Paragraph topic coherence SD: 0.0169578431755 0.0443174109184 38% => Paragraphs are similar to each other. Some content may get duplicated or it is not exactly right on the topic.
Essay readability:
automated_readability_index: 15.1 13.3589403974 113% => OK
flesch_reading_ease: 53.55 53.8541721854 99% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 12.3 11.0289183223 112% => OK
coleman_liau_index: 11.49 12.2367328918 94% => OK
dale_chall_readability_score: 8.27 8.42419426049 98% => OK
difficult_words: 74.0 63.6247240618 116% => OK
linsear_write_formula: 10.5 10.7273730684 98% => OK
gunning_fog: 12.4 10.498013245 118% => OK
text_standard: 12.0 11.2008830022 107% => OK
What are above readability scores?
---------------------
Write the essay in 20 minutes.
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.