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.
The reading passage describes that a special marine mammal around the Siberia which khown as Steller' s sea became extinct because some reason. While the speaker strongly is disagreed with this claim.
The speaker says that the sea cows are very massive and big which some times they have 19 feet length. So she says that it is impossible that the native Siberian people, who had very low density , were the cause of this distinction. because one sea caw could response their needs for a while.
The lucturer also refutes the reading' s claim about the ecological event in 1768 and says that it just not impercived the Kelps but other animals also had been in danger. while there are no evidence that the Whales destroid during this time, so its not a correct answer for this problem.
Finally, she claims that the European fur traders who entered after 1741 were not the cause of this etinction.since the evidence is shown that the population of sea cows were decreased about 100 years before the Eropean arrived to Sibria.
So she says that she is not convinced by the explanation of reading passage reasons for extinction of sea crows.
Grammar and spelling errors:
Line 1, column 144, Rule ID: SENTENCE_FRAGMENT[1]
Message: “While” 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.
...sea became extinct because some reason. While the speaker strongly is disagreed with ...
^^^^^
Line 3, column 195, Rule ID: COMMA_PARENTHESIS_WHITESPACE
Message: Put a space after the comma, but not before the comma
Suggestion: ,
...iberian people, who had very low density , were the cause of this distinction. bec...
^^
Line 3, column 234, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: Because
...y , were the cause of this distinction. because one sea caw could response their needs ...
^^^^^^^
Line 5, column 172, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: While
... other animals also had been in danger. while there are no evidence that the Whales d...
^^^^^
Line 7, column 95, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...entered after 1741 were not the cause of this etinction.since the evidence is sho...
^^
Transition Words or Phrases used:
also, but, finally, so, while
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 10.0 10.4613686534 96% => OK
Auxiliary verbs: 1.0 5.04856512141 20% => OK
Conjunction : 3.0 7.30242825607 41% => More conjunction wanted.
Relative clauses : 13.0 12.0772626932 108% => OK
Pronoun: 23.0 22.412803532 103% => OK
Preposition: 17.0 30.3222958057 56% => More preposition wanted.
Nominalization: 7.0 5.01324503311 140% => OK
Performance on vocabulary words:
No of characters: 950.0 1373.03311258 69% => OK
No of words: 198.0 270.72406181 73% => More content wanted.
Chars per words: 4.79797979798 5.08290768461 94% => OK
Fourth root words length: 3.75116612262 4.04702891845 93% => OK
Word Length SD: 2.3428513182 2.5805825403 91% => OK
Unique words: 121.0 145.348785872 83% => More unique words wanted.
Unique words percentage: 0.611111111111 0.540411800872 113% => OK
syllable_count: 288.9 419.366225166 69% => 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: 3.0 8.23620309051 36% => OK
Subordination: 4.0 1.25165562914 320% => Less adverbial clause wanted.
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 1.0 2.5761589404 39% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 9.0 13.0662251656 69% => 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: 22.0 21.2450331126 104% => OK
Sentence length SD: 52.9381190112 49.2860985944 107% => OK
Chars per sentence: 105.555555556 110.228320801 96% => OK
Words per sentence: 22.0 21.698381199 101% => OK
Discourse Markers: 3.22222222222 7.06452816374 46% => More transition words/phrases wanted.
Paragraphs: 5.0 4.09492273731 122% => OK
Language errors: 5.0 4.19205298013 119% => OK
Sentences with positive sentiment : 1.0 4.33554083885 23% => More positive sentences wanted.
Sentences with negative sentiment : 5.0 4.45695364238 112% => 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: 0.130345579291 0.272083759551 48% => OK
Sentence topic coherence: 0.0533660980492 0.0996497079465 54% => OK
Sentence topic coherence SD: 0.0640107726433 0.0662205650399 97% => OK
Paragraph topic coherence: 0.074153103832 0.162205337803 46% => OK
Paragraph topic coherence SD: 0.0564279928593 0.0443174109184 127% => OK
Essay readability:
automated_readability_index: 12.2 13.3589403974 91% => Automated_readability_index is low.
flesch_reading_ease: 57.61 53.8541721854 107% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 10.7 11.0289183223 97% => OK
coleman_liau_index: 10.56 12.2367328918 86% => OK
dale_chall_readability_score: 8.32 8.42419426049 99% => OK
difficult_words: 45.0 63.6247240618 71% => More difficult words wanted.
linsear_write_formula: 7.5 10.7273730684 70% => OK
gunning_fog: 10.8 10.498013245 103% => OK
text_standard: 11.0 11.2008830022 98% => OK
What are above readability scores?
---------------------
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.