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 Europeans 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.
Both the reading and the lecture talk about the real cause or causes of marine large animal extinction. Its name is Stellar’s sea cow. This huge mammal lived on Bering Island in Syberia. They are worlds apart in this issue. While the article enumerate three theories for this happening around 1768, the professor finds all those ideas problematic and then rebuts all the author’s proposal.
First, the professor repudiates this idea that overhunting by local islanders could be the main reason of Stellar’s wipe out. He proves that native villagers might kill some sea cow, since they were gigantic, something around nine meter long and ten tone kilograms, one sea cow could feed them for a month. Therefore, he directly rejects the writer's idea and asserts that it is not a rationale reason that the sea cows extinct because of overhunting by a small group of people.
Second, the professor states that if the writer’s second theory about the shortage of sea cow’s food was correct, it would affect other sea animal’s population like whales. As we do not have any evidence or record about the decline in whales or other sea large mammals’ population, we cannot consider the famine and shortage of Kelp (sea cow’s food) as a major cause of Stellar’s sea cow’s extinction. With this justification he rebuts the reading hypothesis about the food shortage because of climate change.
Third, the article mentions that European Fur traders who could kill sea animals quickly with their weapons arrived in the Island around 1764 and they kill them to until extincted condition. On the other hand, the lecturer challenges this opinion by explaining that the sea cow’s extinction happened before European fur trader's arrival. Stellar’s sea cows extincted soon before them at 1700. He believes that something else had happened which had led to sea cow’s extinction. According to this data, the European traders could not be the reason of this animal’s extinction, the professor says.
Grammar and spelling errors:
Line 3, column 1, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...en rebuts all the author’s proposal. First, the professor repudiates this ide...
^^^^^
Line 3, column 237, Rule ID: CD_NN[1]
Message: Possible agreement error. The noun 'meter' seems to be countable, so consider using: 'meters'.
Suggestion: meters
...ey were gigantic, something around nine meter long and ten tone kilograms, one sea co...
^^^^^
Line 3, column 348, Rule ID: POSSESIVE_APOSTROPHE[1]
Message: Possible typo: apostrophe is missing. Did you mean 'writers'' or 'writer's'?
Suggestion: writers'; writer's
...nth. Therefore, he directly rejects the writers idea and asserts that it is not a ratio...
^^^^^^^
Line 5, column 1, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...hunting by a small group of people. Second, the professor states that if the...
^^^^^^
Line 7, column 1, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...shortage because of climate change. Third, the article mentions that Europea...
^^^^^
Line 7, column 326, Rule ID: POSSESIVE_APOSTROPHE[2]
Message: Possible typo: apostrophe is missing. Did you mean 'traders'' or 'trader's'?
Suggestion: traders'; trader's
...extinction happened before European fur traders arrival. Stellar’s sea cows extincted s...
^^^^^^^
Transition Words or Phrases used:
but, first, if, second, so, then, therefore, third, while, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 7.0 10.4613686534 67% => OK
Auxiliary verbs: 7.0 5.04856512141 139% => OK
Conjunction : 9.0 7.30242825607 123% => OK
Relative clauses : 10.0 12.0772626932 83% => OK
Pronoun: 33.0 22.412803532 147% => Less pronouns wanted
Preposition: 37.0 30.3222958057 122% => OK
Nominalization: 10.0 5.01324503311 199% => OK
Performance on vocabulary words:
No of characters: 1683.0 1373.03311258 123% => OK
No of words: 327.0 270.72406181 121% => OK
Chars per words: 5.14678899083 5.08290768461 101% => OK
Fourth root words length: 4.25242769721 4.04702891845 105% => OK
Word Length SD: 2.56894931892 2.5805825403 100% => OK
Unique words: 183.0 145.348785872 126% => OK
Unique words percentage: 0.559633027523 0.540411800872 104% => OK
syllable_count: 500.4 419.366225166 119% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 8.0 3.25607064018 246% => Less pronouns wanted as sentence beginning.
Article: 7.0 8.23620309051 85% => OK
Subordination: 3.0 1.25165562914 240% => Less adverbial clause wanted.
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 16.0 13.0662251656 122% => OK
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 58.8683648066 49.2860985944 119% => OK
Chars per sentence: 105.1875 110.228320801 95% => OK
Words per sentence: 20.4375 21.698381199 94% => OK
Discourse Markers: 4.75 7.06452816374 67% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 6.0 4.19205298013 143% => OK
Sentences with positive sentiment : 3.0 4.33554083885 69% => OK
Sentences with negative sentiment : 6.0 4.45695364238 135% => 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: 0.205898989663 0.272083759551 76% => OK
Sentence topic coherence: 0.0738231780783 0.0996497079465 74% => OK
Sentence topic coherence SD: 0.0486667629059 0.0662205650399 73% => OK
Paragraph topic coherence: 0.126812443472 0.162205337803 78% => OK
Paragraph topic coherence SD: 0.016901160213 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: 13.0 13.3589403974 97% => OK
flesch_reading_ease: 59.64 53.8541721854 111% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 9.9 11.0289183223 90% => OK
coleman_liau_index: 12.59 12.2367328918 103% => OK
dale_chall_readability_score: 8.35 8.42419426049 99% => OK
difficult_words: 77.0 63.6247240618 121% => OK
linsear_write_formula: 6.5 10.7273730684 61% => OK
gunning_fog: 10.0 10.498013245 95% => OK
text_standard: 10.0 11.2008830022 89% => OK
What are above readability scores?
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Write the essay in 20 minutes.
Rates: 75.0 out of 100
Scores by essay e-grader: 22.5 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.