At the end of the Triassic period 200 million years ago, there was a mass-extinction event that caused the extinction of more than half of all living species. It was this extinction event that allowed dinosaurs to become the dominant species for the next 145 million years. We do not know exactly what happened that eliminated so many species in a relatively short period of time, but there are several possible explanations.
One theory involves the decline of sea levels. Near the end of the Triassic period, sea levels were fluctuating. When sea levels fall, the habitats for ocean populations that live in the shallows and land species that live on the coast are destroyed. The destruction of coastal and shallow-ocean species would have had a profound effect on food chains worldwide, leading to mass extinctions.
Another theory involves massive climate cooling. The end of the Triassic period was marked by widespread volcanic activity. The volcanoes released large amounts of sulfur dioxide (S02). A rise in atmospheric S02 is known to cause a lowering in global temperatures. Such climate change could have devastated many species and led to the extinctions.
The third theory involves an asteroid strike. Asteroids (objects from outer space) occasionally collide with Earth. When an asteroid hits Earth’s surface, it often displaces large amounts of soil and crushed rock, leaving behind a depression, or crater. The displaced debris is thrown up into the atmosphere where it can block out sunlight for many months or even a few years. A sufficiently massive asteroid impact at the end of the Triassic period may have blocked sunlight long enough for most plants to die and many animal species to then starve.
The reading and the lecture are both about mass extinction which occurs at the end of the Triassic period. The reading states that there are some theories which contribute in to explanations for this mass extinction. In contrast, the professor explains that these theories may be plausible, but are not good explanation for this occurrence.
First, the passage avers that scientists believe that falling the sea level may be responsible for extinction of species which live in the shallow water and near the beaches. The professor refutes this point by saying that it is true that scientists agree that sea level often fluctuated and may going down in that time, but the species which lived near the costal areas and shallow water could adapt themselves with gradual changes. Therefore, they could survived in that time because the variation in the sea level was a quite gradual change, and very sudden change needed to cause such mass extinction.
Second, the article posits that climate cooling may resulted in mass extinction because at the end of the Triassic period, there is a lot of SO2 gas in the air, which could reduced the temperature. However, the professor explains that this gas always remain in the atmosphere for short amount of time, and also, some amount of this gas currently is present in atmosphere. Moreover, this gas can clear out from the air since SO2 can combine with water in the air and come back to the earth with rain fall.
Third, the reading states that an asteroid which collide with earth may thrown up some particles to the atmosphere which could block the sunlight, and killed the plants and animals. The lecturer opposes this point by stating that the scientists do not believe this theory because the evidence from the site that asteroid hit shows us that the asteroid collide with earth some million years ago before the mass extinction.
| Post date | Users | Rates | Link to Content |
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| 2020-01-17 | nusybah | 80 | view |
| 2019-11-14 | M.S 2019 | 76 | view |
| 2019-10-24 | p0uya | 65 | view |
| 2019-10-24 | Seema Modak | 71 | view |
| 2019-10-08 | mahan vahab kashi | 80 | view |
- Do you agree or disagree? All university students should be required to take history courses no matter what their field of study is. Use specific reasons and examples to support your answer. 70
- Do you agree or disagree with the following statement? It is better to use printed material such as books and articles to do research than it is to use the Internet. Use specific reasons and examples to support your answer. 76
- At the end of the Triassic period 200 million years ago, there was a mass-extinction event that caused the extinction of more than half of all living species. It was this extinction event that allowed dinosaurs to become the dominant species for the next 70
Grammar and spelling errors:
Line 5, column 457, Rule ID: DID_BASEFORM[1]
Message: The verb 'could' requires the base form of the verb: 'survive'
Suggestion: survive
... gradual changes. Therefore, they could survived in that time because the variation in t...
^^^^^^^^
Line 13, column 73, Rule ID: PRP_PAST_PART[3]
Message: Did you mean 'throw' or 'be thrown'?
Suggestion: throw; be thrown
...n asteroid which collide with earth may thrown up some particles to the atmosphere whi...
^^^^^^
Transition Words or Phrases used:
also, but, first, however, may, moreover, second, so, therefore, third, in contrast, it is true
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 9.0 10.4613686534 86% => OK
Auxiliary verbs: 11.0 5.04856512141 218% => Less auxiliary verb wanted.
Conjunction : 11.0 7.30242825607 151% => OK
Relative clauses : 22.0 12.0772626932 182% => OK
Pronoun: 28.0 22.412803532 125% => Less pronouns wanted
Preposition: 40.0 30.3222958057 132% => OK
Nominalization: 10.0 5.01324503311 199% => OK
Performance on vocabulary words:
No of characters: 1574.0 1373.03311258 115% => OK
No of words: 318.0 270.72406181 117% => OK
Chars per words: 4.94968553459 5.08290768461 97% => OK
Fourth root words length: 4.22286093782 4.04702891845 104% => OK
Word Length SD: 2.40698980819 2.5805825403 93% => OK
Unique words: 155.0 145.348785872 107% => OK
Unique words percentage: 0.487421383648 0.540411800872 90% => More unique words wanted or less content wanted.
syllable_count: 460.8 419.366225166 110% => OK
avg_syllables_per_word: 1.4 1.55342163355 90% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 9.0 8.23620309051 109% => OK
Subordination: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 5.0 1.51434878587 330% => Less conjunction wanted as sentence beginning.
Preposition: 1.0 2.5761589404 39% => More preposition wanted as sentence beginning.
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: 28.0 21.2450331126 132% => The Avg. Sentence Length is relatively long.
Sentence length SD: 47.5265910781 49.2860985944 96% => OK
Chars per sentence: 143.090909091 110.228320801 130% => OK
Words per sentence: 28.9090909091 21.698381199 133% => OK
Discourse Markers: 8.63636363636 7.06452816374 122% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 2.0 4.19205298013 48% => OK
Sentences with positive sentiment : 4.0 4.33554083885 92% => OK
Sentences with negative sentiment : 3.0 4.45695364238 67% => OK
Sentences with neutral sentiment: 4.0 4.27373068433 94% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.189542264464 0.272083759551 70% => OK
Sentence topic coherence: 0.082755015093 0.0996497079465 83% => OK
Sentence topic coherence SD: 0.0636352677855 0.0662205650399 96% => OK
Paragraph topic coherence: 0.117104160693 0.162205337803 72% => OK
Paragraph topic coherence SD: 0.0416349039739 0.0443174109184 94% => OK
Essay readability:
automated_readability_index: 16.3 13.3589403974 122% => OK
flesch_reading_ease: 59.98 53.8541721854 111% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 11.8 11.0289183223 107% => OK
coleman_liau_index: 12.02 12.2367328918 98% => OK
dale_chall_readability_score: 8.15 8.42419426049 97% => OK
difficult_words: 63.0 63.6247240618 99% => OK
linsear_write_formula: 10.5 10.7273730684 98% => OK
gunning_fog: 13.2 10.498013245 126% => OK
text_standard: 12.0 11.2008830022 107% => OK
What are above readability scores?
---------------------
Rates: 70 out of 100
Scores by essay e-grader: 21 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.