▶ Your Answer :
In the lecture, the lecturer
cast doubts on the idea of the reading passage that a
new species transported to a new area can cause several negative effects on the
area. The lecturer argues
that not only does a new species always have bad effects on an area, but
also it may lead to good consequences.
First, the lecturer contradicts the idea that a new
species always upset the local ecological balance. Specifically, whereas the reading passage
indicates that a new species, which is unsuitable as food in the food
chain of a new area, may necessarily ruin the ecological balance of the area displacing
native competitors, the
lecturer maintains that some species can make a contribution to the
ecological balance of a new area. The lecturer gives an example of wheat transported
to Kansas.
Second, according to the reading passage, a new species
usually destroy the local environment. On the contrary, the lecturer contradicts this idea by
giving an example of cane toads which also supports the idea of the reading as an example. Whereas the reading passage
indicates that cane toads transported from South Africa to Australia
killed a lot of native species, and the venom in their bodies posed threats to children
and pets in Australia, the
lecturer points out the fact that cane toads played a pivotal role in
reducing the number of garden insects and rats.
Finally, the idea of the reading passage that a new species
can become an economic burden to a given area is rebutted by the lecturer. The lecturer argues that it
depends on which part of economy you look at. For example, whereas the reading passage pays
attention to the fact that mesquites introduced to Africa displaced native
species, which led the government to put a great amount of their resources into
control of the ecological balance, the lecturer points out that mesquites also brought about
significant benefits to Africa as they became a great source of valuable
multi-purpose productions such as fire wood and high quality timber. |