Passage Discussion

[hnadgauda]

Passage A

1st para: The old view of the effect of foreign plants and animal species on ecosystems is not complete. The old view, as exemplified by Charles Elton's view, says that habitats that are already disturbed are more susceptible to destruction by new arrivals because they have less native species to use as defense. This is not true! Even pristine habitats are susceptible to as much destruction as these disturbed habitats were believed to have been.

2nd para: Examples of how invasive plants affect ecosystems and threaten biodiversity.

Passage B

1st para: New species in an ecosystem isn't necessarily a bad thing. Sometimes, introducing a new species actually increases biodiversity!

2nd para: Builds on 1st para. New species can change ecosystems. This isn't always bad--the fact that they change ecosystems doesn't mean they destroy ecosystems.

3rd para: Introducing species to an ecosystem should be seen as a continuum rather than a choice between nature's life and nature's death.


Overall discussion/scale:

Passage A: Sees the introduction of new species to an ecosystem as a negative and as something that will potentially hurt biodiversity.

Passage B: Sees the introduction of new species to an ecosystem on a scale; it could be a good thing or a bad thing; this phenomenon will change the ecosystem--not for humans to decide if it will be for the better or for the worse.