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.
The reading claims that the invasion of the zebra mussel cannot be stopped and it is a threat to freshwater fish populations in all of North America. However, the lecturer finds all the ideas dubious and provides some evidence to refute them all.
The reading holds the view that the history of the zebra mussel's spread shows that the invasion cannot be stopped because ships help them spreading out along new canals. In contrast, the speaker brings up the idea that this phenomenon can be stopped through an effective mechanism. For example, the ships can be refilled with ocean water instead of fresh water and in this way, the zebra fishes will be killed by the salt in the water.
Furthermore, the reading passage argues that zebra mussels can dominate a new habitat due to their characteristics. On the contrary, the lecturer underlines the fact that in the beginning, it might be true, but soon after that, some marine creatures realize that a new source of food is available and the leave their current source of food and start feeding on the zebra mussel. Therefore, the zebra mussels are not so lucky to dominate the new habitat.
Finally, the author asserts that zebra mussels compete for food with other fish species since they eat planktons and as zebra mussels dominants the habitat, it leads to a decline in the fish population. Conversely, the professor dismisses this issue due to the fact that at first glance it might be true, but there are sea bottom fish which feed on wastes which are generated by the zebra mussels and consequently when their source food increases, the population of these bottom fishes increase too. The more plankton the zebra mussels eat, the more food is available for the bottom fishes. As a result, the overall fish population in habitat increases.
| Post date | Users | Rates | Link to Content |
|---|---|---|---|
| 2019-08-20 | Shayooooon | 80 | view |
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Grammar and spelling errors:
Line 3, column 139, Rule ID: ADVISE_VBG[9]
Message: The verb 'help' is used with infinitive: 'to spread' or 'spread'.
Suggestion: to spread; spread
...nnot be stopped because ships help them spreading out along new canals. In contrast, the ...
^^^^^^^^^
Transition Words or Phrases used:
but, consequently, conversely, finally, first, furthermore, however, so, therefore, for example, in contrast, as a result, on the contrary
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 13.0 10.4613686534 124% => OK
Auxiliary verbs: 8.0 5.04856512141 158% => OK
Conjunction : 9.0 7.30242825607 123% => OK
Relative clauses : 13.0 12.0772626932 108% => OK
Pronoun: 24.0 22.412803532 107% => OK
Preposition: 34.0 30.3222958057 112% => OK
Nominalization: 4.0 5.01324503311 80% => OK
Performance on vocabulary words:
No of characters: 1498.0 1373.03311258 109% => OK
No of words: 307.0 270.72406181 113% => OK
Chars per words: 4.87947882736 5.08290768461 96% => OK
Fourth root words length: 4.18585898806 4.04702891845 103% => OK
Word Length SD: 2.46838490979 2.5805825403 96% => OK
Unique words: 156.0 145.348785872 107% => OK
Unique words percentage: 0.508143322476 0.540411800872 94% => More unique words wanted or less content wanted.
syllable_count: 456.3 419.366225166 109% => OK
avg_syllables_per_word: 1.5 1.55342163355 97% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 15.0 8.23620309051 182% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 2.0 1.51434878587 132% => OK
Preposition: 2.0 2.5761589404 78% => OK
Performance on sentences:
How many sentences: 12.0 13.0662251656 92% => OK
Sentence length: 25.0 21.2450331126 118% => OK
Sentence length SD: 70.5220119301 49.2860985944 143% => OK
Chars per sentence: 124.833333333 110.228320801 113% => OK
Words per sentence: 25.5833333333 21.698381199 118% => OK
Discourse Markers: 11.5 7.06452816374 163% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 1.0 4.19205298013 24% => OK
Sentences with positive sentiment : 5.0 4.33554083885 115% => OK
Sentences with negative sentiment : 5.0 4.45695364238 112% => OK
Sentences with neutral sentiment: 2.0 4.27373068433 47% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.225626071699 0.272083759551 83% => OK
Sentence topic coherence: 0.0968461866361 0.0996497079465 97% => OK
Sentence topic coherence SD: 0.0750988416681 0.0662205650399 113% => OK
Paragraph topic coherence: 0.145467052363 0.162205337803 90% => OK
Paragraph topic coherence SD: 0.0405796958532 0.0443174109184 92% => OK
Essay readability:
automated_readability_index: 14.3 13.3589403974 107% => OK
flesch_reading_ease: 54.56 53.8541721854 101% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 11.9 11.0289183223 108% => OK
coleman_liau_index: 11.32 12.2367328918 93% => OK
dale_chall_readability_score: 8.22 8.42419426049 98% => OK
difficult_words: 65.0 63.6247240618 102% => OK
linsear_write_formula: 10.5 10.7273730684 98% => OK
gunning_fog: 12.0 10.498013245 114% => OK
text_standard: 12.0 11.2008830022 107% => OK
What are above readability scores?
---------------------
Rates: 80 out of 100
Scores by essay e-grader: 24 Out of 30
---------------------
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.