TPO-24 - Integrated Writing Task 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

Reading and lecture are both debating whether or not the material founded in a rex's leg bone is animal tissues. On the one hand, the writer states that it is animal tissues and provides three reasons of support. However, the lecturer cast doubts on the claims made by the writer, saying that his arguments make him be skeptical when compares them with real facts. First, the presence of the soft flexible substance can have another explanation. When an organism dies, its hallow places such as bones are colonized by bacteria colonies. In other words, this small organism lives insides the bones and leave behind the organic material, which is as soft as the one from the bones the researcher found. Therefore, this standpoint is directly contradicted by the lecturer. Second, there are numerous other fossils which show that primitive animals didn't have the red blood cells while they were alive. Thereby, the red blood mark must represent something else such as reddish materials. As a result, this also gainsays the passage. Third, it is absolutely impossible to find collagen in those fossils because they are 75 million years old. The writer states that researchers found collagen over the bones, and this proves that they are dealing with animal tissues. Anyway, the speaker refutes this statement, adding that collagen can resist maximum 100 000 years, whereas the fossils are much older. In short, if this theory is authentic, everything people know about collagen is not true. One possible explanation for the presence of collagen is that this might come from the hands of people who handled the bones. Thus, the author's reason is once again dismantled by solid proof.