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 modem 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.
According to the passage, dinosaurs are considered as endotherms because of their abilities to live in the polar areas, leg position underneath its body, and the discovery of Haversian canals within bone structure. However, the professor refutes this idea with the following reasons.
First of all, the article claims the discovery of dinosaur fossils in Polar regions indicating the ability to maintain temperature among certain range. Yet, the professor provides another explanation to this. In the ancient time, the temperature of Polar Regions is warmer compared to it is nowadays; therefore, dinosaur could live without being endotherms easily. Moreover, dinosaur could migrate to warmer area or even hibernate to survive the extreme cold weather.
Secondly, the article points out that the similarity of leg position between dinosaurs and modern endotherms. Again, the professor contradictories this perspective by proposing a theory. She suggests that the legs underneath the body provide weight support to dinosaurs rather than sustain high energy activity such as running.
Lastly, the article says that one of the compositions of bones of dinosaurs, Haversian canals, an indicator of rapid growth, implies that dinosaurs are indeed endotherms. Again, the professor argues that the discovery of inconsistency of growth ring, another indicator of growth rate of dinosaurs within bone, shows the evidence that dinosaurs are not endotherms.
In conclusion, by proposing different explanation to the discovery of fossil in Polar Regions, leg positions of dinosaurs, and Haversian canals, the professor refutes the theory that dinosaurs are endotherms.
| Post date | Users | Rates | Link to Content |
|---|---|---|---|
| 2020-01-21 | liboooyang | 81 | view |
| 2020-01-04 | Tharwat | 83 | view |
| 2019-12-19 | savikx | 66 | view |
| 2019-12-18 | TEJAS PATIL | 80 | view |
| 2019-12-14 | fafar | 80 | view |
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Transition Words or Phrases used:
first, however, if, lastly, moreover, second, secondly, so, therefore, in conclusion, such as, first of all
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 7.0 10.4613686534 67% => OK
Auxiliary verbs: 2.0 5.04856512141 40% => OK
Conjunction : 4.0 7.30242825607 55% => More conjunction wanted.
Relative clauses : 7.0 12.0772626932 58% => More relative clauses wanted.
Pronoun: 14.0 22.412803532 62% => OK
Preposition: 41.0 30.3222958057 135% => OK
Nominalization: 5.0 5.01324503311 100% => OK
Performance on vocabulary words:
No of characters: 1430.0 1373.03311258 104% => OK
No of words: 247.0 270.72406181 91% => More content wanted.
Chars per words: 5.78947368421 5.08290768461 114% => OK
Fourth root words length: 3.96437052324 4.04702891845 98% => OK
Word Length SD: 2.90512278557 2.5805825403 113% => OK
Unique words: 136.0 145.348785872 94% => More unique words wanted.
Unique words percentage: 0.550607287449 0.540411800872 102% => OK
syllable_count: 447.3 419.366225166 107% => OK
avg_syllables_per_word: 1.8 1.55342163355 116% => 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: 2.0 1.51434878587 132% => OK
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 12.0 13.0662251656 92% => OK
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 52.1729894997 49.2860985944 106% => OK
Chars per sentence: 119.166666667 110.228320801 108% => OK
Words per sentence: 20.5833333333 21.698381199 95% => OK
Discourse Markers: 8.91666666667 7.06452816374 126% => OK
Paragraphs: 5.0 4.09492273731 122% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 7.0 4.33554083885 161% => OK
Sentences with negative sentiment : 1.0 4.45695364238 22% => More negative sentences wanted.
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: 0.142501442141 0.272083759551 52% => OK
Sentence topic coherence: 0.0508433872899 0.0996497079465 51% => OK
Sentence topic coherence SD: 0.0403240417826 0.0662205650399 61% => OK
Paragraph topic coherence: 0.0752360178605 0.162205337803 46% => OK
Paragraph topic coherence SD: 0.0392989573092 0.0443174109184 89% => OK
Essay readability:
automated_readability_index: 16.1 13.3589403974 121% => OK
flesch_reading_ease: 34.26 53.8541721854 64% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 13.5 11.0289183223 122% => OK
coleman_liau_index: 16.3 12.2367328918 133% => OK
dale_chall_readability_score: 9.55 8.42419426049 113% => OK
difficult_words: 77.0 63.6247240618 121% => OK
linsear_write_formula: 12.0 10.7273730684 112% => OK
gunning_fog: 10.0 10.498013245 95% => OK
text_standard: 10.0 11.2008830022 89% => OK
What are above readability scores?
---------------------
Rates: 80.0 out of 100
Scores by essay e-grader: 24.0 Out of 30
---------------------
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.