Endotherms are animals such as modern birds and mammals that keep their body temperatures constant. For instance, humans are endotherms and maintain an internal temperature of 37°C, no matter whether the environment is warm or cold. Because dinosaurs were reptiles, and modern reptiles are not endotherms, it was long assumed that dinosaurs were not endotherms. However, dinosaurs differ in many ways from modern reptiles, and there is now considerable evidence that dinosaurs were, in fact, endotherms.
Polar dinosaurs One reason for believing that dinosaurs were endotherms is that dinosaur fossils have been discovered in polar regions. Only animals that can maintain a temperature well above that of the surrounding environment could be active in such cold climates.
Leg position and movement There is a connection between endothermy and the position and movement of the legs. The physiology of endothermy allows sustained physical activity, such as running. But running is efficient only if an animal’s legs are positioned underneath its body, not at the body’s side, as they are for crocodiles and many lizards. The legs of all modern endotherms are underneath the body, and so were the legs of dinosaurs. This strongly suggests that dinosaurs were endotherms.
Haversian canals There is also a connection between endothermy and bone structure. The bones of endotherms usually include structures called Haversian canals. These canals house nerves and blood vessels that allow the living animal to grow quickly, and rapid body growth is in fact a characteristic of endothermy. The presence of Haversian canals in bone is a strong indicator that the animal is an endotherm, and fossilized bones of dinosaurs are usually dense with Haversian canals.
Many scientists have problems with the arguments you read in the passage. They don’t think those arguments prove that dinosaurs were endotherms
Take the polar dinosaur argument. When dinosaurs lived, even the polar regions where dinosaur fossils have been found were much warmer than today—warm enough during part of the year for animals that were not endotherms to live. And during the months when the polar regions were cold, the so-called polar dinosaurs could have migrated to warmer areas or hibernated like many modern reptiles do. So the presence of dinosaur fossils in polar regions doesn’t prove the dinosaurs were endotherms.
Well, what about the fact that dinosaurs had their legs placed under their bodies, not out to the side, like a crocodile’s? That doesn’t necessarily mean dinosaurs were highenergy endotherms built for running. There’s another explanation for having legs under the body: this body structure supports more weight. So with the legs under their bodies, dinosaurs could grow to a very large size. Being large had advantages for dinosaurs, so we don’t need the idea of endothermy and running to explain why dinosaurs evolved to have their legs under their bodies.
OK, so how about bone structure? Many dinosaur bones do have Haversian canals, that’s true, but dinosaur bones also have growth rings. Growth rings are a thickening of the bone that indicates periods of time when the dinosaurs weren’t rapidly growing. These growth rings are evidence that dinosaurs stopped growing or grew more slowly during cooler periods. This pattern of periodic growth—ya know, rapid growth followed by no growth or slow growth and then rapid growth again—is characteristic of animals that are not endotherms. Animals that maintain a constant body temperature year round, as true endotherms do, grow rapidly even when the environment becomes cool.
The topic talks about whether dinosaurs are of endotherms or not. In this reading passage, it makes three points to suggest dinosaurs are certainly endotherms. however, the professor in the lecture makes several points against the passage.
First, in the lecture, the professor says dinosaurs fossils found in polar regions could be migrated from other warm regions or they were just in hibernate. Or even the polar regions were much warmer than it is today. In contrast, the passage claims only endotherms could be able to survive in polar regions. Because mere animals with constant temperature could survive in such cold environment.
Second point is about dinosaurs' leg structure. The teacher claims legs underneath dinosaurs' bodies are used to sustain their heavy weight. They're unnecessary to run for their heavy body weight. however, the passage suggests a linkage between endothermy and leg position. legs underneath dinosuar's bodies could help them run. that's vital trait that dinosaurs belong to endotherms. Otherwise, like crocodiles having legs by body's side would like to run efficiently.
Finally, about the bone structure. The professor indicates that it's truth that most dinosaurs have Haversian canals, however their growth is not rapid all the times. Instead, its speed is periodically switching from rapid to slow and then back to rapid pace. Therefore, it's not a consistent rapidly growing which is a trait that endothermy has. In the contrary, the reading passage suggests that quick body growth could be a key determinant factor to attribute dinosaurs to endothermy.
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| 2020-01-21 | liboooyang | 81 | view |
| 2020-01-04 | Tharwat | 83 | view |
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| 2019-12-18 | TEJAS PATIL | 80 | view |
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Grammar and spelling errors:
Line 1, column 161, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: However
...est dinosaurs are certainly endotherms. however, the professor in the lecture makes sev...
^^^^^^^
Line 3, column 310, Rule ID: SENTENCE_FRAGMENT[1]
Message: “Because” 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.
...ld be able to survive in polar regions. Because mere animals with constant temperature ...
^^^^^^^
Line 5, column 126, Rule ID: HEAVY_WEIGHT[1]
Message: Did you mean 'heavyweight'?
Suggestion: heavyweight
...osaurs bodies are used to sustain their heavy weight. Theyre unnecessary to run for their he...
^^^^^^^^^^^^
Line 5, column 140, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: They're
...are used to sustain their heavy weight. Theyre unnecessary to run for their heavy body...
^^^^^^
Line 5, column 195, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: However
...ary to run for their heavy body weight. however, the passage suggests a linkage between...
^^^^^^^
Line 5, column 272, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: Legs
...ge between endothermy and leg position. legs underneath dinosuars bodies could help ...
^^^^
Line 5, column 326, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: Thats
...h dinosuars bodies could help them run. thats vital trait that dinosaurs belong to en...
^^^^^
Line 5, column 326, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: that's
...h dinosuars bodies could help them run. thats vital trait that dinosaurs belong to en...
^^^^^
Line 7, column 271, Rule ID: IT_IS[6]
Message: Did you mean 'it's' (='it is') instead of 'its' (possessive pronoun)?
Suggestion: it's; it is
...and then back to rapid pace. Therefore, its not a consistent rapidly growing which ...
^^^
Transition Words or Phrases used:
but, finally, first, however, second, so, then, therefore, in contrast
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 13.0 10.4613686534 124% => OK
Auxiliary verbs: 6.0 5.04856512141 119% => OK
Conjunction : 5.0 7.30242825607 68% => OK
Relative clauses : 6.0 12.0772626932 50% => More relative clauses wanted.
Pronoun: 16.0 22.412803532 71% => OK
Preposition: 33.0 30.3222958057 109% => OK
Nominalization: 2.0 5.01324503311 40% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1345.0 1373.03311258 98% => OK
No of words: 250.0 270.72406181 92% => More content wanted.
Chars per words: 5.38 5.08290768461 106% => OK
Fourth root words length: 3.97635364384 4.04702891845 98% => OK
Word Length SD: 2.6505969139 2.5805825403 103% => OK
Unique words: 147.0 145.348785872 101% => OK
Unique words percentage: 0.588 0.540411800872 109% => OK
syllable_count: 406.8 419.366225166 97% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 3.0 3.25607064018 92% => OK
Article: 8.0 8.23620309051 97% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 6.0 2.5761589404 233% => Less preposition wanted as sentence beginnings.
Performance on sentences:
How many sentences: 19.0 13.0662251656 145% => OK
Sentence length: 13.0 21.2450331126 61% => The Avg. Sentence Length is relatively short.
Sentence length SD: 31.0845509454 49.2860985944 63% => OK
Chars per sentence: 70.7894736842 110.228320801 64% => OK
Words per sentence: 13.1578947368 21.698381199 61% => OK
Discourse Markers: 3.68421052632 7.06452816374 52% => More transition words/phrases wanted.
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 9.0 4.19205298013 215% => Less language errors wanted.
Sentences with positive sentiment : 8.0 4.33554083885 185% => OK
Sentences with negative sentiment : 1.0 4.45695364238 22% => More negative sentences wanted.
Sentences with neutral sentiment: 10.0 4.27373068433 234% => Less facts, knowledge or examples wanted.
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.163528120998 0.272083759551 60% => OK
Sentence topic coherence: 0.0493445494315 0.0996497079465 50% => OK
Sentence topic coherence SD: 0.0592563383857 0.0662205650399 89% => OK
Paragraph topic coherence: 0.0875910190868 0.162205337803 54% => OK
Paragraph topic coherence SD: 0.0319719496314 0.0443174109184 72% => OK
Essay readability:
automated_readability_index: 10.5 13.3589403974 79% => Automated_readability_index is low.
flesch_reading_ease: 58.28 53.8541721854 108% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 8.4 11.0289183223 76% => OK
coleman_liau_index: 13.04 12.2367328918 107% => OK
dale_chall_readability_score: 8.13 8.42419426049 97% => OK
difficult_words: 61.0 63.6247240618 96% => OK
linsear_write_formula: 6.5 10.7273730684 61% => OK
gunning_fog: 7.2 10.498013245 69% => OK
text_standard: 8.0 11.2008830022 71% => OK
What are above readability scores?
---------------------
Rates: 66.6666666667 out of 100
Scores by essay e-grader: 20.0 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.