TPO 39 Integrated

Both the reading and the lecture discuss the explanations of the mass extinction at the end of the Triassic period. While the reading provides three possible theories, the lecturer expresses an opposite view and gives several reasons to support her refutation.

First of all, the writer points out that the extinction may be affected by the decline of sea levels. Although the speaker agrees that the sea levels were fluctuating, it needs to be much more sudden for causing the extinction. The fact that this decline happens gradually allows the environment to adapt to this change, striking out the possibility of destroying habitats for species.

Secondly, the author claims that the widespread volcanic activity may have caused massive climate cooling and led to the extinction. However, the professor argues that the volcanoes released large amounts of SO2 in a relatively short period, the mechanism of Earth can clear out SO2 so that the global temperatures will not decrease. As a result, such activities did not devastate species.

Last but not least, the third theory in the passage states that the long-term insufficient sunlight caused by a massive asteroid may be the reason. The scholar once again opposes this idea by proposing the searching of where and when the asteroid hit. Researchers only found one asteroid that is big enough to cause the mass extinction, but it did not happen at the end of the Traissic period. Therefore, this hypothesis is implausible, too.