integrated tpo 26

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The article and the lecture are both contradicting each other, in terms of the invasion of the zebra mussel. More specifically, the author of the article presented three theories to prove that it is hard to stop the invasion of mussels into North America that in turn causes a serious impact on the fish population living in the freshwater. However, the lecturer casts doubt about the hypothesis presented in the article and provides some evidence to refute them.

According to the article, the first dispute focuses on the history of overtaking the habitat in Europe by mussels whereby these mussels attach to the ship's bottom and carry themselves through the ballast water to the new habitat where they will start growing. This same situation will happen to North America very soon through human transportation. Nonetheless, the professor undermines the theory presented in the article. Furthermore, he declares that the invasion of mussels happened before since people did not have enough knowledge about it. But now, people can stop this invasion by emptying fresh water before the ship enters North America, and mussels cannot survive in the saltwater. Thus, their population cannot grow in the new habitat.

Moreover, another topic highlights that since there are no predators available to prey mussels, it is very likely that their population would dominate soon in the new habitat. Nevertheless, the speaker negates this by asserting that it is fact that initially, the mussels population can dominate in the new area, however, as soon as birds in that area would know about the presence of mussels, they would start eating mussels. Hence, their population will decline again.

Finally, the text explains that mussels feed on plankton easters which is the food source of the fish who live in the same habitat, and thereby, the fish population would gradually decline. On the contrary, the penman rebuts this point and describes that the presence of mussels has a positive effect on the fish population because they produce organic nutrients from the food they eat which accumulate at the bottom surface. In fact, this food seems to have good nutrients for the fish who live at the bottom of the habitat. Therefore, the positive effect outweighs the negative sides of living mussels in the new habitat.