TPO 39 EXTINCTION

The reading passage and lecture both are about an enormous extinction event which led extinction to many living species. The author of the passage strongly suggests that there are various possible reasons that eliminated species in a short time. On the other hand, the listening adamantly delineates that none of the author's reasons are of good explanations of extinction at the end of the Triassic period.

First, according to the author of the excerpt, extinction of many species involves decrease in sea levels. It is states in the article that when sea levels decline, the habitats and land species, live on the coast are destroyed. However, the professor explains that coastal and shallow water is capable of adapting to environmental changes. In other words, fall in sea levels was quite gradual. So, change would have to be much more sudden on the species living in the ecosystems.

Next, the author contends that extinction also involves huge climate cooling. In contrast, the lecturer states that it is true that the sulfur dioxide can decrease global temperatures, but that can happen during a short period of time. Moreover, the sulfur dioxide releases by volcanoes, still present in the atmosphere. Basically, the sulfur dioxide mixes with water in the atmosphere but it is not likely that volcanic sulfur dioxide released at the end of the Triassic period, it stayed in the atmosphere long enough to cause extinction.

Finally, the author claims that asteroids collide with Earth. When it hits the surface of the Earth, it displaces extensive amounts of soil and crushed rock, leaves behind crater. Nevertheless, the lecturer asserts that nobody found any asteroid crater dated back when massive extinction occurred. They did find a crater, but twelve million years before the extinction took place. It is too long before the extinction to have anything to do with it.