Earthworms, Writing, Test 4, Delta

In the passage, the author mainly talks about the positive effects that earthworms can have on forest ecosystem and in gardens. However, the speaker of the speech casts doubt on that proclamation in several aspects.

Firstly, according to the speaker, earthworms can induce to substantial damage to forest ecosystem in respect that earthworms destroy the cover of soil, which causes native organisms to disappear from that place. In the passage, the author writes that worms are beneficial for forests, which is contrary to what is said by the speaker. Moreover, the speaker says that earthworms can have huge repellant effects on forest ecosystem.

Secondly, when it comes to the matter of forest duff, the speaker and the author also disagree about the influences that earthworms pose when they bring duff deeper into the soil. In the article, the author believes that, in such process, earthworms move organic matter from the surface deeper into soil, which is beneficial for the production of organic fertilizer. Nevertheless, the speaker opposes this perspective and points out that this phenomenon will cause soil losing nutrients more rapidly. Furthermore, the speaker cites a scientific experiment led by a ecologist as evidence. In that experiment, earthworms that live near a fish lake are examined. When earthworms bring duff deeper into soil, the thick and abundant layer becomes disappeared.

Finally, the speaker also refers to the point that other animals are also harmfully influenced by earthworms, which is not mentioned in the passage. In the speaker's opinion, because earthworms have eaten the entire duff on the surface of the soil, other animals, such as spiders, birds, do not have enough food to feed on. As a result, the quantities of these animals decrease.