A huge marine mammal known as Steller’s sea cow once lived in the waters around Bering Island off the coast of Siberia. It was described in 1741 by Georg W. Steller, a naturalist who was among the first European to see one. In 1768 the animal became extinct. The reasons for the extinction are not clear. Here are three theories about the main cause of the extinction.
First, the sea cows may have been overhunted by groups of native Siberian people. If this theory is correct, then the sea cow population would have originally been quite large, but hundreds of years off too much hunting by the native people diminished the number of sea cows. Sea cows were a good source of food in a harsh environment, so overhunting by native people could have been the main cause of extinction.
Second, the sea cow population may have become extinct because of ecosystems disturbances that caused a decline in their main source of food, kelp (a type of sea plant). Kelp populations respond negatively to a number of ecological changes. It is possible that ecological changes near Bering island some time before 1768 caused a decrease of the kelp that the sea cows depend on.
Third, the main cause of extinction of the sea cows could have been European fur traders who came to the island after 1741. It is recorded that the fur traders caught the last sea cow in 1768. It thus seems reasonable to believe that hunting by European fur traders, who possessed weapons that allowed them to quickly kill a large number of the animals, was the main cause of the sea cow’s extinction.
The reading passage and lecture have conflicting opinions about the causes of sea cow extinction before 1768. The article strongly postulates that in 1768 the sea cow became extinct. However, there are three assumptions that would explain the reasons for the sea cow extinction. On the other hand, the listening adamantly delinates that the main reason behind the extinction is not to know yet. Whatever none of the three theories is convincing.
First and foremost, according to the author of the excerpt, the sea cows might have declined in population because of the overhunting of the native people. In other words, the sea cows population started decreasing after the Siberian individuals started killing and eating sea cows. Nonetheless, the lecture offsets these points by declaring that the sea cow was massive, nine meters long and 10 ton. However, one sea cow would have fed the whole Siberian village. Also, the population of the Siberian at that time was small. Meaning that the native people wouldn't have hunted a lot of sea cows.
On top of this, the professor in the lecture further points out that the decline in kelp population would have resulted from severe damage to the ecosystems before 1768. Whereas, none of the fishing ships were reported about decline in other kind fishes, for instance, whales. As a result, the sea cows didn't experience food shortage. These claims refute the writer implications of how the disturbance of the ecosystems would have destroyed the main source of sea cow food.
The article lastly asserts that the European trader's arrival could have been the cause of sea cows extinction. Furthermore, there are some records show that the fur traders hunted the last sea cow in 1768 owing to the fact that they had sophisticated weapons that would help. The speaker in lecture counters these points by declaring that the sea cow population would have been in decline before the arrival of the European. Also, there was some thing serious caused the extinction.
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Grammar and spelling errors:
Line 3, column 181, Rule ID: POSSESIVE_APOSTROPHE[1]
Message: Possible typo: apostrophe is missing. Did you mean 'cows'' or 'cow's'?
Suggestion: cows'; cow's
... native people. In other words, the sea cows population started decreasing after the...
^^^^
Line 3, column 558, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: wouldn't
...s small. Meaning that the native people wouldnt have hunted a lot of sea cows. On to...
^^^^^^^
Line 5, column 304, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: didn't
...ance, whales. As a result, the sea cows didnt experience food shortage. These claims ...
^^^^^
Line 7, column 46, Rule ID: POSSESIVE_APOSTROPHE[1]
Message: Possible typo: apostrophe is missing. Did you mean 'traders'' or 'trader's'?
Suggestion: traders'; trader's
...rticle lastly asserts that the European traders arrival could have been the cause of se...
^^^^^^^
Line 7, column 442, Rule ID: ANY_BODY[2]
Message: Did you mean 'something'?
Suggestion: something
...rrival of the European. Also, there was some thing serious caused the extinction.
^^^^^^^^^^
Transition Words or Phrases used:
also, first, furthermore, however, lastly, nonetheless, so, whereas, for instance, as a result, in other words, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 10.0 10.4613686534 96% => OK
Auxiliary verbs: 8.0 5.04856512141 158% => OK
Conjunction : 5.0 7.30242825607 68% => OK
Relative clauses : 12.0 12.0772626932 99% => OK
Pronoun: 17.0 22.412803532 76% => OK
Preposition: 40.0 30.3222958057 132% => OK
Nominalization: 13.0 5.01324503311 259% => Less nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1681.0 1373.03311258 122% => OK
No of words: 332.0 270.72406181 123% => OK
Chars per words: 5.06325301205 5.08290768461 100% => OK
Fourth root words length: 4.2685907696 4.04702891845 105% => OK
Word Length SD: 2.5262789971 2.5805825403 98% => OK
Unique words: 164.0 145.348785872 113% => OK
Unique words percentage: 0.493975903614 0.540411800872 91% => More unique words wanted or less content wanted.
syllable_count: 507.6 419.366225166 121% => 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: 11.0 8.23620309051 134% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 19.0 13.0662251656 145% => OK
Sentence length: 17.0 21.2450331126 80% => The Avg. Sentence Length is relatively short.
Sentence length SD: 38.1390516088 49.2860985944 77% => OK
Chars per sentence: 88.4736842105 110.228320801 80% => OK
Words per sentence: 17.4736842105 21.698381199 81% => OK
Discourse Markers: 6.78947368421 7.06452816374 96% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 5.0 4.19205298013 119% => OK
Sentences with positive sentiment : 6.0 4.33554083885 138% => OK
Sentences with negative sentiment : 5.0 4.45695364238 112% => OK
Sentences with neutral sentiment: 8.0 4.27373068433 187% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.148316612262 0.272083759551 55% => OK
Sentence topic coherence: 0.056133399399 0.0996497079465 56% => OK
Sentence topic coherence SD: 0.0339534040656 0.0662205650399 51% => OK
Paragraph topic coherence: 0.0978679641092 0.162205337803 60% => OK
Paragraph topic coherence SD: 0.0296807721305 0.0443174109184 67% => OK
Essay readability:
automated_readability_index: 11.1 13.3589403974 83% => Automated_readability_index is low.
flesch_reading_ease: 62.68 53.8541721854 116% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 8.7 11.0289183223 79% => OK
coleman_liau_index: 11.77 12.2367328918 96% => OK
dale_chall_readability_score: 8.05 8.42419426049 96% => OK
difficult_words: 75.0 63.6247240618 118% => OK
linsear_write_formula: 8.0 10.7273730684 75% => OK
gunning_fog: 8.8 10.498013245 84% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
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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.