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.
According to the lecturer and the reading, there are several positive points about animal fossils and several negative points about animal fossils. The lecturer explains that is no longer remnant inside a dinosaur bones. However, the reading passage contends that a dinosaur, might still contain remains of the actual tissues of the animal.
The first point that the lecturer makes it that the soft flexible substance inside channels of bone is not remnant of red blood cell. According to the professor, It maybe bacteria, that colonize the channels. And the blood vessels might be the traces of soft and moist that left by bacteria. This point from the lecturer contrasts with the reading because the reading only says that This soft substance inside channels may very well represent the remains of the actual blood vessels of T. rex leg bone.
Another point that the lecturer uses to cast doubt on the reading is that the spheres is just remnant of reddish minerals, However the reading only states that spheres that could be the remains of red blood cells.
Finally, the professor stated that, on the contrary of the reading, there is no remnant of collagen. In other words, remnant in collagen cannot last long than one hundred thousand years. The most exact reason that the collagen
is present is not from T. rex's but from human skin.
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However the reading only states that spheres that could be the remains of red blood cells.
However the reading only states that spheres could be the remains of red blood cells.
that the collagen is present is not from
that the collagen presents is not from
Attribute Value Ideal
Score: 24 in 30
Category: Good Excellent
No. of Grammatical Errors: 2 2
No. of Spelling Errors: 0 2
No. of Sentences: 11 12
No. of Words: 227 250
No. of Characters: 1090 1200
No. of Different Words: 111 150
Fourth Root of Number of Words: 3.882 4.2
Average Word Length: 4.802 4.6
Word Length SD: 2.132 2.4
No. of Words greater than 5 chars: 82 80
No. of Words greater than 6 chars: 66 60
No. of Words greater than 7 chars: 32 40
No. of Words greater than 8 chars: 8 20
Use of Passive Voice (%): 0 0
Avg. Sentence Length: 20.636 21.0
Sentence Length SD: 8.563 7.5
Use of Discourse Markers (%): 0.636 0.12
Sentence-Text Coherence: 0.401 0.35
Sentence-Para Coherence: 0.627 0.50
Sentence-Sentence Coherence: 0.106 0.07
Number of Paragraphs: 4 4