Pterosaurs were an ancient group of winged reptiles that lived alongside the dinosaurs. Many pterosaurs were very large, some as large as a giraffe and with a wingspan of over 12 meters. Paleontologists have long wondered whether large pterosaurs were capable of powered flight (flying by flapping their wings) or whether they were able only to glide. Several arguments have been made against powered flight.
Doubters point out that since modern reptiles are cold-blooded, ancient reptiles such as pterosaurs were probably cold-blooded as well. Cold-blooded animals typically have a slow metabolism and are unable to produce a lot of energy. Powered flight is an activity requiring a lot of energy, which is why all modern vertebrates that fly are warm-blooded, not cold-blooded. It seemed unlikely that pterosaurs would have been able to generate the energy needed to fly.
Second, there is a limit to the weight of animals that can be kept airborne by powered flight. Pterosaurs that were as large as a giraffe were probably so heavy that they would not have been able to flap their wings fast enough to stay aloft for any length of time.
Third, all animals with powered flight are able to take off from the ground. For example, birds take off by jumping from their legs or running to gain speed and then jumping. But these methods would not have worked for large pterosaurs. Large pterosaurs would have needed big, powerful muscles in their back legs to launch themselves into the air, and we know from fossilized bones that their back leg muscles were too small and weak to allow the pterosaurs to run fast enough or jump high enough to launch themselves into the air.
Now listen to part of a lecture on the topic you just read about.
Recent research has revealed that pterosaurs may, in fact, have been capable of powered flight.
First, the issue of pterosaur metabolism. Some recently discovered pterosaur fossils indicate that pterosaurs had a dense, hairlike covering, somewhat similar to fur. Hair or fur covering is typical of warm-blooded animals because those animals need to maintain a high body temperature when external conditions are cold. So, if the metabolism of pterosaurs was more like that of warm-blooded animals, and so faster than the reading suggests, then it would have supplied them with the energy needed for powered flight.
Second, the idea that large pterosaurs couldn’t use powered flight because they were too heavy. We now know that pterosaurs had anatomical features that made them unusually light for their size. For example, the bones of pterosaurs were hollow instead of solid. Hollow, lightweight bones would have kept the pterosaurs’ weight low despite their large body frames. The pterosaurs’ weight was probably low enough to allow them to keep themselves airborne by flapping their wings. Third, takeoff would indeed be a problem for pterosaurs—if they took off the way birds do. But there are important differences between birds and pterosaurs. Birds only use their hind limbs—their legs—for walking on the ground, so they only have two limbs to push off from when they launch. But pterosaurs walked on all four limbs while on the ground.
There are modern flying animals that walk on all four limbs—bats, for example—and they use all four limbs to push off the ground, not just the back ones. Studies indicate that even the largest pterosaurs would’ve had no trouble using all four limbs to run fast enough or jump high enough to launch themselves into the air.
Summarize the points made in the lecture, being sure to explain how they oppose the specific points made in the reading passage.
The reading and lecture are both about the powered flight ability of pterosaurs. The author of the passage feels that the winged reptiles could not fly by flapping their wings. The lecturer challenges the claims made by the writer. He is of the opinion that these explanations are faulty.
To begin with, the author argues that ancient reptiles were cold-blooded. The article mentions that they are unable to generate sufficient energy to fly. This specific argument is challenged by the lecturer. He claims that the recent discovery of pterosaurs' fossil reveals that they have dense fur or hair. As a result, these reptiles could probably maintain a high body temperature. Accordingly, he said that they would have supplied enough energy to fly.
Secondly, the writer suggests that the ancient reptiles are too massive to able to fly. The lecturer, however, refutes this by mentioning that bones of pterosaurs are hollow instead of solid. He elaborates on this by bringing up the point that these structures enable them to be very light despite their big size. Consequently, their weight is low enough to fly.
Finally, the author posits that pterosaurs' back leg muscles were significantly small and weak to allow them to run and jump to launch to the air. In contrast, the lecturer's position is that pterosaurs used all four back legs to launch into the sky, unlike birds that can take off by jumping two legs. Hence, they did not need high powerful muscles in their back legs to fly.
| Post date | Users | Rates | Link to Content |
|---|---|---|---|
| 2020-05-30 | thichngaodu27 | 73 | view |
| 2020-05-30 | thichngaodu27 | 78 | view |
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Grammar and spelling errors:
Line 1, column 178, Rule ID: ENGLISH_WORD_REPEAT_BEGINNING_RULE
Message: Three successive sentences begin with the same word. Reword the sentence or use a thesaurus to find a synonym.
... could not fly by flapping their wings. The lecturer challenges the claims made by ...
^^^
Transition Words or Phrases used:
accordingly, consequently, finally, hence, however, if, second, secondly, so, in contrast, as a result, to begin with
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 12.0 10.4613686534 115% => OK
Auxiliary verbs: 5.0 5.04856512141 99% => OK
Conjunction : 4.0 7.30242825607 55% => More conjunction wanted.
Relative clauses : 13.0 12.0772626932 108% => OK
Pronoun: 33.0 22.412803532 147% => Less pronouns wanted
Preposition: 35.0 30.3222958057 115% => 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: 1245.0 1373.03311258 91% => OK
No of words: 251.0 270.72406181 93% => More content wanted.
Chars per words: 4.96015936255 5.08290768461 98% => OK
Fourth root words length: 3.98032404683 4.04702891845 98% => OK
Word Length SD: 2.54213239312 2.5805825403 99% => OK
Unique words: 145.0 145.348785872 100% => OK
Unique words percentage: 0.577689243028 0.540411800872 107% => OK
syllable_count: 376.2 419.366225166 90% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 8.0 3.25607064018 246% => Less pronouns wanted as sentence beginning.
Article: 9.0 8.23620309051 109% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 2.0 2.5761589404 78% => OK
Performance on sentences:
How many sentences: 17.0 13.0662251656 130% => OK
Sentence length: 14.0 21.2450331126 66% => The Avg. Sentence Length is relatively short.
Sentence length SD: 29.7237569985 49.2860985944 60% => OK
Chars per sentence: 73.2352941176 110.228320801 66% => OK
Words per sentence: 14.7647058824 21.698381199 68% => OK
Discourse Markers: 6.88235294118 7.06452816374 97% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 5.0 4.33554083885 115% => OK
Sentences with negative sentiment : 6.0 4.45695364238 135% => OK
Sentences with neutral sentiment: 6.0 4.27373068433 140% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.137277806698 0.272083759551 50% => OK
Sentence topic coherence: 0.0394596910643 0.0996497079465 40% => Sentence topic similarity is low.
Sentence topic coherence SD: 0.0484618210278 0.0662205650399 73% => OK
Paragraph topic coherence: 0.0757572353253 0.162205337803 47% => OK
Paragraph topic coherence SD: 0.0344209537428 0.0443174109184 78% => OK
Essay readability:
automated_readability_index: 9.3 13.3589403974 70% => Automated_readability_index is low.
flesch_reading_ease: 65.73 53.8541721854 122% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 7.6 11.0289183223 69% => OK
coleman_liau_index: 10.9 12.2367328918 89% => OK
dale_chall_readability_score: 8.29 8.42419426049 98% => OK
difficult_words: 63.0 63.6247240618 99% => OK
linsear_write_formula: 5.5 10.7273730684 51% => Linsear_write_formula is low.
gunning_fog: 7.6 10.498013245 72% => OK
text_standard: 8.0 11.2008830022 71% => OK
What are above readability scores?
---------------------
Rates: 75.0 out of 100
Scores by essay e-grader: 22.5 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.