Animal fossils usually provide very little opportunity to study the actual animal tissues, because in fossils the animals' living tissues have been largely replaced by minerals. Thus, scientists were very excited recently when it appeared that a 70-million-year-old fossil of Tyrannosaurus rex (T. rex), a dinosaur, might still contain remains of the actual tissues of the animal. The discovery was made when researchers deliberately broke open the T. rex’s leg bone, thereby exposing its insides to reveal materials that seem to be remains of blood vessels, red blood cells, and collagen matrix.
First, the breaking of the fossilized leg bone revealed many small branching channels inside, which probably correspond to hollows in the bones where blood vessels were once located. The exciting finding was the presence of a soft, flexible organic substance inside the channels. This soft substance may very well represent the remains of the actual blood vessels of T. rex.
Second, microscopic examination of the various parts of the inner bone revealed the presence of spheres that could be the remains of red blood cells. Tests showed that the spheres contained iron-a material vital to the role of red blood cells in transporting oxygen to tissues. Moreover, the spheres had dark red centers (substances with iron tend to be reddish in color) and were also about the size of red blood cells.
Third, scientists performed a test on the dinosaur leg bone that showed that it contained collagen. Collagen is a fibrous protein that is a main component of living bone tissue, in which it forms a so-called collagen matrix. Collagen (or its chemical derivatives) is exactly the kind of biochemical material that one would expect to find in association with bone tissue.
The reading states that although fossils do not give much information to scientists, but recently one fossil of one animal from millions years ago reveal materials as same as blood tissues and providing three reasons in the reading the author support this observation. However, the professor in the lecture says some skeptical identification exist against the reasons mentioned in the reading.
First of all, the professor in the lecture posits that the soft tissue remained in the bones of the fossil of this animal, is not remnant of blood tissues but it is the moist residue left by bacteria colony. She explains that these bacteria colonize on the empty places such as holes of the bone, so the soft tissue is something like bacteria lived long inside organism. Although, the reading claims that this soft tissue is remained of blood vessels.
Secondly, according to the professor, the reddish substances in the bone are something different of blood cells. He adds that they can be reddish mineral. Besides, the fossils of other animals in same place reveal the iron, thus it strengthen the reason that this reddish spheres are not blood cells. On the contrary the reading ascertains that this spheres present the blood cell in the bones.
Finally, the professor goes on to refute the last claim in the reading by explaining that Collagen cannot be found in defunct which are older than thousands of years, and thus, this Collagens has been found in this fossils is from another source like the human skin like researcher handling the bone. Yet the author confirms the Collagen found in the bone corroborates the bone tissue, because this protein just associated with living bone tissue and he is negligible about the age of bones, which is millions of years .
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| 2018-11-28 | Mohammed AlKhars | 3 | view |
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although fossils do not give much information to scientists, but recently one
Description: Don't put 'although' 'but' in one sentence.
one fossil of one animal from millions years ago reveal...
one fossil of one animal from millions years ago reveals...
providing three reasons in the reading the author support this observation.
providing three reasons in the reading to support this observation.
thus it strengthen the reason that this reddish spheres are not blood cells.
thus it strengthens the reason that this reddish spheres are not blood cells.
ascertains that this spheres present the blood cell in the bones.
ascertains that these spheres present the blood cell in the bones.
Sentence: Finally, the professor goes on to refute the last claim in the reading by explaining that Collagen cannot be found in defunct which are older than thousands of years, and thus, this Collagens has been found in this fossils is from another source like the human skin like researcher handling the bone.
Description: A determiner/pronoun, singular is not usually followed by a noun, plural, common
Suggestion: Refer to this and fossils
flaws:
No. of Grammatical Errors: 6 2
Same grammar issues.
Attribute Value Ideal
Score: 22 in 30
Category: Good Excellent
No. of Grammatical Errors: 6 2
No. of Spelling Errors: 0 2
No. of Sentences: 11 12
No. of Words: 296 250
No. of Characters: 1439 1200
No. of Different Words: 148 150
Fourth Root of Number of Words: 4.148 4.2
Average Word Length: 4.861 4.6
Word Length SD: 2.386 2.4
No. of Words greater than 5 chars: 104 80
No. of Words greater than 6 chars: 80 60
No. of Words greater than 7 chars: 45 40
No. of Words greater than 8 chars: 26 20
Use of Passive Voice (%): 0 0
Avg. Sentence Length: 26.909 21.0
Sentence Length SD: 13.447 7.5
Use of Discourse Markers (%): 0.727 0.12
Sentence-Text Coherence: 0.407 0.35
Sentence-Para Coherence: 0.652 0.50
Sentence-Sentence Coherence: 0.193 0.07
Number of Paragraphs: 4 4