The zebra mussel, a freshwater shellfish native to Eastern Europe, has long been spreading out from its original habitats and has now reached parts of North America. There are reasons to believe that this invasion cannot be stopped and that it poses a serious threat to freshwater fish populations in all of North America.
First, the history of the zebra mussel's spread suggests that the invasion might be unstoppable. It is a prime example of an invasion made possible by human transportation. From the zebra mussel，s original habitats in Eastern Europe, ships helped spread it out along new canals built to connect Europe’s waterways. The mussel can attach itself to a ship’ s bottom or can survive in the water—called "ballast water"—that the ship needs to take on to properly balance its cargo. By the early nineteenth century, the mussel had spread to the whole of Europe. It was later carried to the east coast of North America in the ballast water of ships traveling from Europe. The way ships have spread the zebra mussel inthe past strongly suggests that the species will soon colonize all of North America.
Moreover, once zebra mussels are carried to a new habitat, theycan dominate it. They are a hardy species that does well under a variety of conditions, and they have a high rate of reproduction. Most important, however, zebra mussels often have no predators in their new habitats, and species without natural predators are likely to dominate their habitats.
Finally, zebra mussels are likely to cause a decline in the overall fish population in habitats where they become dominant. The mussels are plankton eaters, which means that they compete for food with many freshwater fish species
Both the article and the lecture discuss the possibility of controlling the spread of the zebra mussel. The article suggested that zebra mussels cannot be controlled once they spread and provided three reasons to support his argument. The lecturer, on the other hand, responded that invasion of zebra mussels can be controlled and eliminated.
To begin with, the article stated that the history of zebra mussels indicated that population of mussels cannot be controlled. The article explained that in the past the zebra mussels have spread in the whole Europe and the ships were the carriers of them. However, the lecturer acknowledged that people in the past could not control the mussels, but he mentioned that people did not have the proper knowledge that allow them to solve this problem. The lecturer suggested that one way to eliminate this problem is by letting ships empty from fresh water to salt water.
Second, the article said that zebra mussels do not have predators, have high reproduction rate, and can live in different environment. According to the writer of the article all of these conditions make the spreading of zebra mussels unstoppable. In contrast, the lecturer pointed out that zebra mussels do not have predators only at the beginning of their life cycle, however aquatic birds will feed on zebra mussels. Therefore, zebra mussels are less likely to be dominant in their ecosystem.
Finally, the author of article emphasized that zebra mussels compete with other fish species for food, which might cause reduction in the fish population. The lecturer, however, argued that zebra mussels might have negative influence on some species in the ocean, on the other hand, it has positive impacts on others. According to the lecturer, zebra mussels generate nutrients, which are crucial to some species.
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Transition Words or Phrases used:
but, finally, however, if, second, so, therefore, in contrast, to begin with, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 8.0 10.4613686534 76% => OK
Auxiliary verbs: 8.0 5.04856512141 158% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 15.0 12.0772626932 124% => OK
Pronoun: 24.0 22.412803532 107% => OK
Preposition: 41.0 30.3222958057 135% => OK
Nominalization: 7.0 5.01324503311 140% => OK
Performance on vocabulary words:
No of characters: 1531.0 1373.03311258 112% => OK
No of words: 296.0 270.72406181 109% => OK
Chars per words: 5.1722972973 5.08290768461 102% => OK
Fourth root words length: 4.14784890444 4.04702891845 102% => OK
Word Length SD: 2.54165219713 2.5805825403 98% => OK
Unique words: 152.0 145.348785872 105% => OK
Unique words percentage: 0.513513513514 0.540411800872 95% => OK
syllable_count: 474.3 419.366225166 113% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 1.0 3.25607064018 31% => OK
Article: 10.0 8.23620309051 121% => OK
Subordination: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 2.0 1.51434878587 132% => OK
Preposition: 6.0 2.5761589404 233% => Less preposition wanted as sentence beginnings.
Performance on sentences:
How many sentences: 14.0 13.0662251656 107% => OK
Sentence length: 21.0 21.2450331126 99% => OK
Sentence length SD: 30.487618765 49.2860985944 62% => OK
Chars per sentence: 109.357142857 110.228320801 99% => OK
Words per sentence: 21.1428571429 21.698381199 97% => OK
Discourse Markers: 6.78571428571 7.06452816374 96% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 3.0 4.33554083885 69% => OK
Sentences with negative sentiment : 3.0 4.45695364238 67% => OK
Sentences with neutral sentiment: 8.0 4.27373068433 187% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.200150076571 0.272083759551 74% => OK
Sentence topic coherence: 0.0866595171783 0.0996497079465 87% => OK
Sentence topic coherence SD: 0.0417187096471 0.0662205650399 63% => OK
Paragraph topic coherence: 0.133462039303 0.162205337803 82% => OK
Paragraph topic coherence SD: 0.0426344068977 0.0443174109184 96% => OK
Essay readability:
automated_readability_index: 13.5 13.3589403974 101% => OK
flesch_reading_ease: 50.16 53.8541721854 93% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 11.5 11.0289183223 104% => OK
coleman_liau_index: 12.71 12.2367328918 104% => OK
dale_chall_readability_score: 8.52 8.42419426049 101% => OK
difficult_words: 72.0 63.6247240618 113% => OK
linsear_write_formula: 11.0 10.7273730684 103% => OK
gunning_fog: 10.4 10.498013245 99% => OK
text_standard: 11.0 11.2008830022 98% => OK
What are above readability scores?
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Rates: 80 out of 100
Scores by essay e-grader: 24 Out of 30
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Note: the e-grader does NOT examine the meaning of words and ideas. VIP users will receive further evaluations by advanced module of e-grader and human graders.