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 of 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 ecosystem 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 depended 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.
Recently, there has been a debate on the Steller's sea cow extinction.More specifically, in the reading passage, the writer puts forth three possible explanations for the extinctions.In the listening, the lecturer is quick to point out that there are some serious flaws in the writers claim.I n fact, the professor believes, and addresses in detail, the trouble with each point made in the reading text.
First and foremost, the author of the reading states that overhunting of the sea cows by the indigenes of Siberia will show an increase in population if it was actually true.Some professionals, in the same field, however, stand in firm opposition to this claim.In the listening, for example, the sea cow are massive because they are 9m long and weigh over ten tons.Besides, cow pea feed herbarium village for months hence they do not cause its extinction.
One group of scholars, represented by the writer, thinks that alteration of the ecosystem causes a decline in their primary food source. Of course, though, not all experts in the field believe this is accurate.Again, the speaker addresses this point by claiming that alteration of the ecosystem would affect other parts because there would be some drastic decrease in marine animals.Hence no report relating to ecosystem was shown.
Finally, the author brings his argument to a close by stating that European fur traders occupying the island after 1741 is another notable cause.Not surprisingly, the speaker takes issue with this by contending that the cowpea has experience extinction before the arrival of the european traders because their populations were minutes.Moreover, the population were extremely large before 1700.
Grammar and spelling errors:
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... states that overhunting of the sea cows by the indigenes of Siberia will show a...
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...tes that overhunting of the sea cows by the indigenes of Siberia will show an in...
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...e in population if it was actually true.Some professionals, in the same field, howev...
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... stand in firm opposition to this claim.In the listening, for example, the sea cow...
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...hey are 9m long and weigh over ten tons.Besides, cow pea feed herbarium village for mon...
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...s in the field believe this is accurate.Again, the speaker addresses this point by cl...
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...some drastic decrease in marine animals.Hence no report relating to ecosystem was sho...
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... because their populations were minutes.Moreover, the population were extremely large be...
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Transition Words or Phrases used:
actually, besides, finally, first, hence, however, if, moreover, so, for example, of course
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 12.0 10.4613686534 115% => OK
Auxiliary verbs: 3.0 5.04856512141 59% => OK
Conjunction : 3.0 7.30242825607 41% => More conjunction wanted.
Relative clauses : 6.0 12.0772626932 50% => More relative clauses wanted.
Pronoun: 18.0 22.412803532 80% => OK
Preposition: 37.0 30.3222958057 122% => OK
Nominalization: 10.0 5.01324503311 199% => OK
Performance on vocabulary words:
No of characters: 1437.0 1373.03311258 105% => OK
No of words: 268.0 270.72406181 99% => OK
Chars per words: 5.36194029851 5.08290768461 105% => OK
Fourth root words length: 4.04607285448 4.04702891845 100% => OK
Word Length SD: 2.98933231805 2.5805825403 116% => OK
Unique words: 167.0 145.348785872 115% => OK
Unique words percentage: 0.623134328358 0.540411800872 115% => OK
syllable_count: 434.7 419.366225166 104% => 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: 10.0 8.23620309051 121% => OK
Subordination: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 5.0 2.5761589404 194% => OK
Performance on sentences:
How many sentences: 5.0 13.0662251656 38% => 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: 53.0 21.2450331126 249% => The Avg. Sentence Length is relatively long.
Sentence length SD: 113.362074787 49.2860985944 230% => The lengths of sentences changed so frequently.
Chars per sentence: 287.4 110.228320801 261% => Less chars_per_sentence wanted.
Words per sentence: 53.6 21.698381199 247% => Less words per sentence wanted.
Discourse Markers: 18.2 7.06452816374 258% => Less transition words/phrases wanted.
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 15.0 4.19205298013 358% => Less language errors wanted.
Sentences with positive sentiment : 1.0 4.33554083885 23% => More positive sentences wanted.
Sentences with negative sentiment : 3.0 4.45695364238 67% => OK
Sentences with neutral sentiment: 1.0 4.27373068433 23% => More facts, knowledge or examples wanted.
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.123614135987 0.272083759551 45% => OK
Sentence topic coherence: 0.0553233430255 0.0996497079465 56% => OK
Sentence topic coherence SD: 0.0261439926608 0.0662205650399 39% => Sentences are similar to each other.
Paragraph topic coherence: 0.0644530802907 0.162205337803 40% => Maybe some paragraphs are off the topic.
Paragraph topic coherence SD: 0.0219706157558 0.0443174109184 50% => 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: 30.6 13.3589403974 229% => Automated_readability_index is high.
flesch_reading_ease: 17.68 53.8541721854 33% => Flesch_reading_ease is low.
smog_index: 14.6 5.55761589404 263% => Smog_index is high.
flesch_kincaid_grade: 24.0 11.0289183223 218% => Flesch kincaid grade is high.
coleman_liau_index: 14.7 12.2367328918 120% => OK
dale_chall_readability_score: 10.51 8.42419426049 125% => OK
difficult_words: 72.0 63.6247240618 113% => OK
linsear_write_formula: 29.5 10.7273730684 275% => Linsear_write_formula is high.
gunning_fog: 23.2 10.498013245 221% => Gunning_fog is high.
text_standard: 15.0 11.2008830022 134% => OK
What are above readability scores?
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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.