TPO 39 Integrated Writing Task

The reading passage talks about why there was a mass extinction of species at the end of the Triassic, and several theories are given in support of this statement. Although these points seem reasonable, the lecturer casts doubt on them for the following reasons.
To begin with, the lecturer concurs with the article that the sea level indeed fluctuated and declined at that time. Nevertheless, she points out that these impacts of fluctuating sea posed on the coast and the shallow ocean were gradual. In addition, she indicates that the coastal and shallow water ecosystems were capable of adapting to the gradual environmental change. Thereby, the lecturer disagrees with the author that the decline of sea levels would eventually lead to mass extinction.
Second, even though the author suggests that the sulfur dioxide released from the volcanoes could lower the temperature and give rise to mass extinctions, the lecturer argued that it can only occur in a relatively short time. Furthermore, since sulfur dioxide can combine with water and fall back to the ground as rain, the lecturer believes that the sulfur dioxide that appeared at the end of the Triassic was unlikely to remain long enough to induce mass extinctions.
Last but not least, the author proposed that the impacts of asteroids might bring about extinction by covering the atmosphere and blocking the sunlight with lots of dust and debris. Conversely, the lecturer acutely identifies the weakness in this asteroid theory, showing that we can’t find craters that can be dated back to the time when the extinction took place. Accordingly, she dismisses this asteroid theory.