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 and the audio mainly discussed the reasons causing the decline in the population of sea otters along the western coast of America. According to the reading, the most important factor is water contamination, however, the lecturer disputes this theory, having said that, this is predation which is the most likely reason for this ongoing extinction.
First, based on the reading, pollution is the more likely cause due to the known sources of oil rigs and industrial chemical pollution along the coast, yet the lecturer disagreed, she explained that this theory cannot be true given the fact that there is no evidence of killed sea otter near the area, which confirms the fact that they were eaten by orcas whale predators.
Second, the passage introduced another reason, suggesting that other mammals such as seals and sea lions were also declining, since the environmental pollution does affect the entire ecosystem rather than being selective to a single species. On the other hand, the woman on the audio argued this hypothesis, she purports that this pattern of declining in other sea mammals has proven the predatory theory more strongly. The investigation on this area reveals that haunting whales by humans which were food for orcas whales had forced them to change their pray to smaller mammals like seals, sea lions, and sea otters.
Third, the reading assets that uneven pattern of the declining sea otter was aligned with water pollution, albeit the lecturer argued this reason, saying that uneven pattern is related to the fact that the more the population of orcas whale is available, the more we are facing the decrease in small sea mammals. She describes that there is a direct link between shallow and rocky coast in which the environment is not appropriate, the rate of declining is smaller, in comparison of deep-marine environment where the incline in the population of the sea otter is more drastic.
Transition Words or Phrases used:
also, first, however, second, so, third, such as, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 18.0 10.4613686534 172% => OK
Auxiliary verbs: 1.0 5.04856512141 20% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 16.0 12.0772626932 132% => OK
Pronoun: 26.0 22.412803532 116% => OK
Preposition: 35.0 30.3222958057 115% => OK
Nominalization: 14.0 5.01324503311 279% => Less nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1625.0 1373.03311258 118% => OK
No of words: 319.0 270.72406181 118% => OK
Chars per words: 5.09404388715 5.08290768461 100% => OK
Fourth root words length: 4.22617688928 4.04702891845 104% => OK
Word Length SD: 2.52472760251 2.5805825403 98% => OK
Unique words: 171.0 145.348785872 118% => OK
Unique words percentage: 0.53605015674 0.540411800872 99% => OK
syllable_count: 495.0 419.366225166 118% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 4.0 3.25607064018 123% => OK
Article: 9.0 8.23620309051 109% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 2.0 1.51434878587 132% => OK
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 8.0 13.0662251656 61% => Need more sentences. Double check the format of sentences, make sure there is a space between two sentences, or have enough periods. And also check the lengths of sentences, maybe they are too long.
Sentence length: 39.0 21.2450331126 184% => The Avg. Sentence Length is relatively long.
Sentence length SD: 69.9428338002 49.2860985944 142% => OK
Chars per sentence: 203.125 110.228320801 184% => OK
Words per sentence: 39.875 21.698381199 184% => OK
Discourse Markers: 8.375 7.06452816374 119% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 1.0 4.33554083885 23% => More positive sentences wanted.
Sentences with negative sentiment : 4.0 4.45695364238 90% => OK
Sentences with neutral sentiment: 3.0 4.27373068433 70% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.255800985947 0.272083759551 94% => OK
Sentence topic coherence: 0.134285042106 0.0996497079465 135% => OK
Sentence topic coherence SD: 0.100938273651 0.0662205650399 152% => OK
Paragraph topic coherence: 0.162662194332 0.162205337803 100% => OK
Paragraph topic coherence SD: 0.0411639550089 0.0443174109184 93% => OK
Essay readability:
automated_readability_index: 22.5 13.3589403974 168% => OK
flesch_reading_ease: 31.89 53.8541721854 59% => Flesch_reading_ease is low.
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 18.5 11.0289183223 168% => OK
coleman_liau_index: 12.83 12.2367328918 105% => OK
dale_chall_readability_score: 9.63 8.42419426049 114% => OK
difficult_words: 82.0 63.6247240618 129% => OK
linsear_write_formula: 18.0 10.7273730684 168% => OK
gunning_fog: 17.6 10.498013245 168% => OK
text_standard: 18.0 11.2008830022 161% => OK
What are above readability scores?
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Rates: 85.0 out of 100
Scores by essay e-grader: 25.5 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.