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.
In the reading passage, the author discusses three kinds of the reasons caused of the see cow extinction, while the lecturer claims that what the reading passage states is not convincing and disputes those reasons presented in the reading passage by several proofs.
First, the reading passage state that the sea cows were overhunted caused the sea cow extinction, while the speaker refutes this view point by saying that the population of the native people weren't so much, besides, the sea cows were very massive creature. Therefore, native people can feed just one sea cow for several month.
Second, the belief in the reading passage is that ecosystems distributions caused a decrease in the sea cows food sources. Consequently, caused their extinction. By contrast, the lecture view to this issue from an opposite angle. According to the lecturer the if ecosystem change causes the sea cow extinction, it should affect to other marine animals. However, there is no significant change occur to other animals’ population, which were lived in the same habitat with the sea cows.
Additionally, the writer in the reading passage states that sea cow extinction has occurred after European fur traders came, so they could have been the cause of the sea cow extinction. Lecturer, on the other hand, demonstrates a different idea that sea cow population were very small when the European fur trader came which in turn shows that their extinction begins before them and may have had another reason.
All in all, the professor clearly identifies the weaknesses in the reading passage and convincingly shows that the presented theory in the reading passage, about the cow extinction, are accurately incorrect.
Grammar and spelling errors:
Line 2, column 192, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: weren't
...hat the population of the native people werent so much, besides, the sea cows were ver...
^^^^^^
Line 2, column 312, Rule ID: MANY_NN[1]
Message: Possible agreement error. The noun month seems to be countable; consider using: 'several months'.
Suggestion: several months
...ve people can feed just one sea cow for several month. Second, the belief in the reading p...
^^^^^^^^^^^^^
Line 4, column 105, Rule ID: POSSESIVE_APOSTROPHE[1]
Message: Possible typo: apostrophe is missing. Did you mean 'cows'' or 'cow's'?
Suggestion: cows'; cow's
...tributions caused a decrease in the sea cows food sources. Consequently, caused thei...
^^^^
Transition Words or Phrases used:
besides, but, consequently, first, however, if, may, second, so, therefore, while, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 9.0 10.4613686534 86% => OK
Auxiliary verbs: 4.0 5.04856512141 79% => OK
Conjunction : 3.0 7.30242825607 41% => More conjunction wanted.
Relative clauses : 11.0 12.0772626932 91% => OK
Pronoun: 16.0 22.412803532 71% => OK
Preposition: 28.0 30.3222958057 92% => OK
Nominalization: 10.0 5.01324503311 199% => OK
Performance on vocabulary words:
No of characters: 1444.0 1373.03311258 105% => OK
No of words: 276.0 270.72406181 102% => OK
Chars per words: 5.23188405797 5.08290768461 103% => OK
Fourth root words length: 4.07593519647 4.04702891845 101% => OK
Word Length SD: 2.68223636812 2.5805825403 104% => OK
Unique words: 149.0 145.348785872 103% => OK
Unique words percentage: 0.539855072464 0.540411800872 100% => OK
syllable_count: 441.9 419.366225166 105% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 1.0 3.25607064018 31% => OK
Article: 7.0 8.23620309051 85% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 5.0 2.5761589404 194% => OK
Performance on sentences:
How many sentences: 11.0 13.0662251656 84% => 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: 25.0 21.2450331126 118% => OK
Sentence length SD: 75.257684048 49.2860985944 153% => OK
Chars per sentence: 131.272727273 110.228320801 119% => OK
Words per sentence: 25.0909090909 21.698381199 116% => OK
Discourse Markers: 9.09090909091 7.06452816374 129% => OK
Paragraphs: 5.0 4.09492273731 122% => OK
Language errors: 3.0 4.19205298013 72% => OK
Sentences with positive sentiment : 2.0 4.33554083885 46% => More positive sentences wanted.
Sentences with negative sentiment : 2.0 4.45695364238 45% => More negative sentences wanted.
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: 0.116337837479 0.272083759551 43% => OK
Sentence topic coherence: 0.0514585835517 0.0996497079465 52% => OK
Sentence topic coherence SD: 0.0342544878376 0.0662205650399 52% => OK
Paragraph topic coherence: 0.066135730047 0.162205337803 41% => OK
Paragraph topic coherence SD: 0.0369319300333 0.0443174109184 83% => OK
Essay readability:
automated_readability_index: 15.7 13.3589403974 118% => OK
flesch_reading_ease: 46.1 53.8541721854 86% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 13.0 11.0289183223 118% => OK
coleman_liau_index: 13.35 12.2367328918 109% => OK
dale_chall_readability_score: 8.54 8.42419426049 101% => OK
difficult_words: 64.0 63.6247240618 101% => OK
linsear_write_formula: 17.5 10.7273730684 163% => OK
gunning_fog: 12.0 10.498013245 114% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
---------------------
Rates: 80.0 out of 100
Scores by essay e-grader: 24.0 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.