The outermost layer of skin, the epidermis, produces a variety of growths in animal and bird species. Because dinosaurs were reptiles, and modern reptiles have scales and armor plates on their skin, it was long assumed that dinosaurs had the same type of skin coverings. However, dinosaurs had many traits that modern reptiles lack, and evidence gathered by paleontologists indicates that dinosaurs may have, in fact, possessed feathers like modern birds.
Descendants
One reason for believing that dinosaurs possessed feathers is that they are a defining trait of their descendants: modern birds. All modern birds have feathers that cover their bodies to some degree, and this is true of all birds in the fossil record as well. Therefore, it is reasonable to assume that they inherited this trait from their ancestors.
Fossil Feathers
There is physical evidence that some dinosaurs did certainly have feathers. Feathers are clearly visible on fossils ranging from the duck-sized Mei Long to the largest known feathered dinosaur, the Yutyrannus huali, a Tyrannosaurus cousin that weighed more than 3,000 pounds.The feathered fossils belong to species that are unrelated and include both predator and prey animals. This strongly suggests that feathers were common to all dinosaurs.
Need for Feathers
While feathers are most commonly associated with flight, they almost certainly evolved first as a way of regulating temperature. Many of the feathers that have left fossil imprints look more like the downy fluff of a modern chick or hatchling than the stiff plumes of adult birds. Such filament-like feathers would likely have been helpful in trapping body heat. Warm-blooded modern birds use feathers to insulate themselves in colder climates and it is reasonable to assume that dinosaurs would have put feathers to the same use.
The reading and the lecture both discuss the possibility that many dinosaur species possessed feathers like modern birds. The reading offers many arguments in favor of this opinion, while the lecture disputes those claims.
First, the reading claims that since all modern and extinct bird species had feathers, it is reasonable to assume that they inherited this trait from their dinosaur ancestors. The lecture agrees that birds probably did inherit their feathers from their ancestors, however, their ancestors were predatory theropod dinosaurs. Plant eating dinosaurs have no living relatives to compare them to, so we cannot assume that they had feathers.
Second, the reading states that there is physical evidence of feathers in many fossils from unrelated dinosaur species, including plant and meat-eaters. The professor admits that some fossils show feathers, however, he points out that many skin impressions show no evidence of feathers at all. In fact, many well-known plant-eating species had scales and armor plates, but no feathers.
Third, the reading says that feathers most likely evolved as a way to stay warm and that many dinosaurs had these filament-like feathers. The professor says that feathers are a good way to stay warm, however, he says that larger dinosaur species probably had another characteristic called gigantothermy. Animals can be so large that their internal temperature does not change much compared to their environment. Large dinosaurs could have used this method over feathers, which would have blocked the sun from their skin.
| Post date | Users | Rates | Link to Content |
|---|---|---|---|
| 2021-10-08 | devvratjoshi | 90 | view |
| 2021-10-03 | devvratjoshi | 71 | view |
| 2021-10-03 | New_account | 81 | view |
| 2021-07-06 | Cookiedough | 90 | view |
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Comments
Essay evaluations by e-grader
Transition Words or Phrases used:
but, first, however, second, so, third, well, while, in fact
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 5.0 10.4613686534 48% => More to be verbs wanted.
Auxiliary verbs: 4.0 5.04856512141 79% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 14.0 12.0772626932 116% => OK
Pronoun: 32.0 22.412803532 143% => Less pronouns wanted
Preposition: 22.0 30.3222958057 73% => OK
Nominalization: 4.0 5.01324503311 80% => OK
Performance on vocabulary words:
No of characters: 1335.0 1373.03311258 97% => OK
No of words: 243.0 270.72406181 90% => More content wanted.
Chars per words: 5.49382716049 5.08290768461 108% => OK
Fourth root words length: 3.94822203886 4.04702891845 98% => OK
Word Length SD: 2.59946179931 2.5805825403 101% => OK
Unique words: 141.0 145.348785872 97% => OK
Unique words percentage: 0.58024691358 0.540411800872 107% => OK
syllable_count: 393.3 419.366225166 94% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 4.0 3.25607064018 123% => OK
Article: 8.0 8.23620309051 97% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 1.0 2.5761589404 39% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 12.0 13.0662251656 92% => OK
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 25.892405579 49.2860985944 53% => The essay contains lots of sentences with the similar length. More sentence varieties wanted.
Chars per sentence: 111.25 110.228320801 101% => OK
Words per sentence: 20.25 21.698381199 93% => OK
Discourse Markers: 5.0 7.06452816374 71% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 5.0 4.33554083885 115% => OK
Sentences with negative sentiment : 4.0 4.45695364238 90% => OK
Sentences with neutral sentiment: 3.0 4.27373068433 70% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.222625263065 0.272083759551 82% => OK
Sentence topic coherence: 0.0867166581557 0.0996497079465 87% => OK
Sentence topic coherence SD: 0.0475899730903 0.0662205650399 72% => OK
Paragraph topic coherence: 0.131051848238 0.162205337803 81% => OK
Paragraph topic coherence SD: 0.0523557736191 0.0443174109184 118% => OK
Essay readability:
automated_readability_index: 14.6 13.3589403974 109% => OK
flesch_reading_ease: 51.18 53.8541721854 95% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 11.1 11.0289183223 101% => OK
coleman_liau_index: 14.56 12.2367328918 119% => OK
dale_chall_readability_score: 8.53 8.42419426049 101% => OK
difficult_words: 60.0 63.6247240618 94% => OK
linsear_write_formula: 11.0 10.7273730684 103% => OK
gunning_fog: 10.0 10.498013245 95% => OK
text_standard: 15.0 11.2008830022 134% => OK
What are above readability scores?
---------------------
Rates: 90.0 out of 100
Scores by essay e-grader: 27.0 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.
Transition Words or Phrases used:
but, first, however, second, so, third, well, while, in fact
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 5.0 10.4613686534 48% => More to be verbs wanted.
Auxiliary verbs: 4.0 5.04856512141 79% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 14.0 12.0772626932 116% => OK
Pronoun: 32.0 22.412803532 143% => Less pronouns wanted
Preposition: 22.0 30.3222958057 73% => OK
Nominalization: 4.0 5.01324503311 80% => OK
Performance on vocabulary words:
No of characters: 1335.0 1373.03311258 97% => OK
No of words: 243.0 270.72406181 90% => More content wanted.
Chars per words: 5.49382716049 5.08290768461 108% => OK
Fourth root words length: 3.94822203886 4.04702891845 98% => OK
Word Length SD: 2.59946179931 2.5805825403 101% => OK
Unique words: 141.0 145.348785872 97% => OK
Unique words percentage: 0.58024691358 0.540411800872 107% => OK
syllable_count: 393.3 419.366225166 94% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 4.0 3.25607064018 123% => OK
Article: 8.0 8.23620309051 97% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 1.0 2.5761589404 39% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 12.0 13.0662251656 92% => OK
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 25.892405579 49.2860985944 53% => The essay contains lots of sentences with the similar length. More sentence varieties wanted.
Chars per sentence: 111.25 110.228320801 101% => OK
Words per sentence: 20.25 21.698381199 93% => OK
Discourse Markers: 5.0 7.06452816374 71% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 5.0 4.33554083885 115% => OK
Sentences with negative sentiment : 4.0 4.45695364238 90% => OK
Sentences with neutral sentiment: 3.0 4.27373068433 70% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.222625263065 0.272083759551 82% => OK
Sentence topic coherence: 0.0867166581557 0.0996497079465 87% => OK
Sentence topic coherence SD: 0.0475899730903 0.0662205650399 72% => OK
Paragraph topic coherence: 0.131051848238 0.162205337803 81% => OK
Paragraph topic coherence SD: 0.0523557736191 0.0443174109184 118% => OK
Essay readability:
automated_readability_index: 14.6 13.3589403974 109% => OK
flesch_reading_ease: 51.18 53.8541721854 95% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 11.1 11.0289183223 101% => OK
coleman_liau_index: 14.56 12.2367328918 119% => OK
dale_chall_readability_score: 8.53 8.42419426049 101% => OK
difficult_words: 60.0 63.6247240618 94% => OK
linsear_write_formula: 11.0 10.7273730684 103% => OK
gunning_fog: 10.0 10.498013245 95% => OK
text_standard: 15.0 11.2008830022 134% => OK
What are above readability scores?
---------------------
Rates: 90.0 out of 100
Scores by essay e-grader: 27.0 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.