TOEFL Sample essay : integrated essay from TPO 15

In this set of materials, the reading passage introduces three different ways to prevent the spread of cane toad in Australia because the cane toad threatens small native animals which are not pests. However, the lecturer believes that it is not as easy to get rid of the cane toad as it is mentioned in the passage and provides some evidence to refute all methods.

First of all, it is mentioned in the passage that a national fence can prevent the toads moving into the places that they have not yet entered. On the contrary, the professor states that national fence is not an effective way to enclose the toads' colonized areas since young toads and their eggs are usually existing in rivers and streams which will flow and carry the toads to the other side of the river. Therefore, the toads will establish their population in the other side of the fence.

Furthermore, the author of the reading passage declares that volunteer people can catch and destroy the toads and their eggs and, by inference, avoid increasing population of the toads. In contrast, the speaker asserts that it is difficult to distinguish between a toad's egg and some native frogs in Australia which, in turn, may damage the ecosystem of the Australia. Although massive volunteers could devastate toads, the untrained people may inadvertently eradicate some endangered frogs in Australia.

Finally, the reading passage touches on researches on disease-causing virus to manage the cane toad populations. Conversely, the professor is totally at odds with virus diffusing through cane toads because diseases can have terrible consequences in their original environment in the Central and South America. The virus will be conveyed to the areas that cane toads hail from by pet collectors and researchers. As the toads are the native species of the America, eliminating them will affect the whole ecosystem and will pose an ecological disaster.