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The lecture rejects the ideas presented in the reading passage that the zebra mussel's invasion cannot be stopped and will threat to other fish populations .In the professor's idea, the zebra mussel's inviasion (invasion) is able to control, and it is still not clear that if sebra (Zebra) mussel is a serious threat to other fish sepiecies. (species)
In the first place, the lecture does not agree with the first point made in the reading that mussel arrived and colonize around North America by surviving in the fresh water used to balance cargos. The professor contends that with knowledges (knowledge) required for now, people can empty those fresh water and fullfill (fulfill) ocean (ocean)water, and the salt of occean (ocean) can kill mussels. Therefore, human transportation would not take mussels to North America, as what it did to Europe.
In the second place, the lecture goes on to refute the claim in the reading that mussel will dominate a new hababit (habitat) after arriving. Actually, the professor argues, what happened in Europe was, mussels reproduce rapidly in the begining (beginning), but those natrual sepieces (species) quickly found mussel as good food and changed their habitats to predate mussels. Those mussels ate a lot of mussels, and stop likely trend of mussels' domination.
In the third place, the lecture challenges that mussels leads to a decline in overall fish population. On the contrary, the lecture reminds us the overall fish population is likely to increase in entirely possibilities. For example, mussels produce new generations in bottom of the river, and many fish species living there feed on those new generations of mussels, thus increase the population of those species. Although, the population of plankton eaters will decerase.(decrease)
All the information above point zebra mussles (mussels) as an unlike threat to other species.
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发表于 2013-9-28 11:21:32
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