Reading part:A fossil skeleton of a dinosaur called Sinosauropteryx, preserved in volcanic ash, was discovered in Liaoning, China, in 1996. Interestingly, the fossil included a pattern of fine lines surrounding the skeletal bones. Some paleontologists int

Essay topics:

Reading part:

A fossil skeleton of a dinosaur called Sinosauropteryx, preserved in volcanic ash, was discovered in Liaoning, China, in 1996. Interestingly, the fossil included a pattern of fine lines surrounding the skeletal bones. Some paleontologists interpret the lines as evidence that Sinosauropteryx had feathers. However, critics have opposed the idea that Sinosauropteryx was a feathered dinosaur, citing several reasons.

First, the critics points out that the fine lines may not even represent functional structures of a living dinosaur, but rather structures that were formed after the animal’s death. After the animal died and was buried in volcanic ash, its skin may have decomposed into fibers. The skin fibers then became preserved as lines in the fossil; the lines were misinterpreted as evidence of feathers.

Second, even if the fine lines are remains of real structures of a Sinosauropteryx, scientists cannot tell with certainty what part of the dinosaur’s anatomy the structures were. Many dinosaurs had frills, ornamental fan-shaped structures growing out of some parts of their bodies. Some of the critics argue that the lines surrounding the skeleton are much more likely to be fossilized remains of frills than remains of feathers.

A third objection is based on the fact that the usual functions of feathers are to help animals fly or regulate their internal temperature. However, the structures represented by the lines in the Sinosauropteryx fossil were mostly located along the backbone and the tail of the animal. This would have made the structures quite useless for flight and of very limited use in thermoregulation. This suggests that the lines do not represent feathers.

Listening part:

The evidence that the lines in the Sinosauropteryx fossil represent feathers is very strong. The arguments of the critics are unconvincing.

First, it is unlikely that the lines are a result of the decomposition of the dinosaur’s skin, because we don’t see any such decomposition in the fossils of other animals buried at the same site. In fact, the fossils of many other animals buried at the site show evidence that their functional skin structures have been beautifully preserved in volcanic ash. The well-preserved condition of the other fossils makes it likely that the Sinosauropteryx’s lines are also well-preserved functional structures, possibly feathers, and that they are not fibers caused by decomposition.

Second, the idea that the lines represent frills… well, there is an important chemical difference between feathers and frills. Feathers contain a great deal of a protein called Beta-keratin. Frills, on the other hand, do not contain beta-keratin. Our chemical analyses suggest that the Sinosauropteryx structures did contain beta-keratin. So that indicates that the structures were feathers, not frills.

Third, feathers can be used for other functions than flight and thermoregulation. Think of a bird, like peacock, for example. The peacock has long, colorful feathers in its tail. And it displays its tail in order to attract a mate. That’s a distinct function of feathers called the display function. Recently, we have been able to do analyses on the Sinosauropteryx structures that show us that the structures were colorful. They were orange and white. The fact that they were colorful strongly supports the idea that they were feathers that this dinosaur use for display.

According to the reading passage, the author proposed three objections that the fine lines surrounding the Sinosauropteryx skeletal bones didn't indicate that Sinosauropteryx had feathers. Nevertheless, the lecturer disagreed with these idea for several reasons.

First, while the critics claimed that the fine lines were possibly formed after the dinosaurs' death, the lecturer thought that this was not convincing. She argued that other fossil skeletons around the same area had well preserved skin structure owing to the protection by the volcanic ash, so it is quite possible that the fine lines found on Sinosauropteryx skeletons were functional skin remains rather than decomposed fibers.

Second, critics maintained that even the fine lines are functional structure of Sinosauropteryx, scientists were still not sure where these structures belonged to. However, the lecturer pointed out that chemical analysis had revealed that those fine lines were composed of beta-keratins which was often found in remains of feathers. On the other hand, beta-keratins were not discovered in frills.

Third, eventhough the fine lines were only noticed on the backbone and tail of the Sinosauropteryx, it didn't nessessarily mean that these structures were not feathers. Feathers could have functions other than flying and thermoregulation. The lecturer further used an example of peacock to explain her view. The long, colorful tail of peacock was used to display rather than fly. They used their tail to attract mates. Since scientists had found out that those fine lines were originally orange and white in color, it was quite possible that Sinosauropteryx used these colorful feathers for other purposes.

Votes
Average: 7.5 (4 votes)
Essay Categories

Comments

beta-keratins which was often found
beta-keratins which were often found

Sentence: Third, eventhough the fine lines were only noticed on the backbone and tail of the Sinosauropteryx, it didn't nessessarily mean that these structures were not feathers.
Error: nessessarily Suggestion: necessarily
Error: eventhough Suggestion: No alternate word

Sentence: Feathers could have functions other than flying and thermoregulation.
Error: thermoregulation Suggestion: No alternate word

Attribute Value Ideal
Score: 24 in 30
Category: Good Excellent
No. of Grammatical Errors: 1 2
No. of Spelling Errors: 3 2
No. of Sentences: 13 12
No. of Words: 260 250
No. of Characters: 1411 1200
No. of Different Words: 140 150
Fourth Root of Number of Words: 4.016 4.2
Average Word Length: 5.427 4.6
Word Length SD: 2.935 2.4
No. of Words greater than 5 chars: 92 80
No. of Words greater than 6 chars: 80 60
No. of Words greater than 7 chars: 60 40
No. of Words greater than 8 chars: 35 20
Use of Passive Voice (%): 0 0
Avg. Sentence Length: 20 21.0
Sentence Length SD: 10.4 7.5
Use of Discourse Markers (%): 0.538 0.12
Sentence-Text Coherence: 0.376 0.35
Sentence-Para Coherence: 0.577 0.50
Sentence-Sentence Coherence: 0.142 0.07
Number of Paragraphs: 4 4