Reading Passage
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.
Summarize the points made in the lecture, being sure to explain how they support/contradict specific points made in the reading passage.
阅读要点概括
1. Some paleontologists interpret the lines as evidence that Sinosauropteryx had feathers. However, critics have opposed this idea.
2. First, the fine lines may not even represent functional structures of a living dinosaur, but rather structures that were formed after the animal’s death.
3. Second, the lines surrounding the skeleton are much more likely to be fossilized remains of frills.
4. A third objection is that the structures represented by the lines in the Sinosauropteryx fossil would have made the structures quite useless for flight and of very limited use in thermoregulation.
听力要点概括
1. The critics’ arguments are not so convincing.
2. First, it is unlikely that the lines are the 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.
3. Second, chemical analysis suggests that the Sinosauropteryx do not contain beta-keratin that frills do not contain, but feathers do.
4. Feathers have other functions, like display function.
