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 in the past strongly suggests that the species will soon colonize all of North America.
Moreover, once zebra mussels are carried to a new habitat, they can 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 reading passage and lecture discuss whether the invasion of zebra mussel can be controlled or not. The former represents three reasons that it might not possible to stop the spread of the zebra mussel from Eastern Europe to North America, but the later refutes each of these three points.
First of all, the author of the passage claims that human trasnsportation might be the reason of expansion of the zebra mussel as it might bind itself to the bottom of the ship's or might be in the ballast water, and this way it might be the dominant species of the North America. However, the lecture contends that it is possible to stop the spread of this mussel through changing ballast water in the cargo. The cargo is required to emplty its whole water in the fresh water and again refilled with the ocean water. This would remove both the mussels which are attached in the ship's bottom along with ballast water.
Secondly, the text asserts that in the new environment, the zebra mussels might have not any predators and their forging rate is quite high. In contrast, the listening counters that at the beginning they might not have any predators. After a while, the sea aquatic bird might notice new species and change their food habit, and would prey the zebra mussels.
In third, the reading passage states that tas the zebra mussels are plankton eater, they might cause negative impact on the overall freshwater fish populations. On the other hand, the lecturer mentions that though it can diminish the certain fish type, it would help to increase bottom water fish through increasing nutrition of the water.
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Transition Words or Phrases used:
but, first, however, second, secondly, so, third, while, in contrast, first of all, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 9.0 10.4613686534 86% => OK
Auxiliary verbs: 14.0 5.04856512141 277% => Less auxiliary verb wanted.
Conjunction : 9.0 7.30242825607 123% => OK
Relative clauses : 8.0 12.0772626932 66% => More relative clauses wanted.
Pronoun: 23.0 22.412803532 103% => OK
Preposition: 33.0 30.3222958057 109% => OK
Nominalization: 3.0 5.01324503311 60% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1346.0 1373.03311258 98% => OK
No of words: 279.0 270.72406181 103% => OK
Chars per words: 4.82437275986 5.08290768461 95% => OK
Fourth root words length: 4.08696624509 4.04702891845 101% => OK
Word Length SD: 2.25415830991 2.5805825403 87% => OK
Unique words: 143.0 145.348785872 98% => OK
Unique words percentage: 0.512544802867 0.540411800872 95% => More unique words wanted or less content wanted.
syllable_count: 396.0 419.366225166 94% => OK
avg_syllables_per_word: 1.4 1.55342163355 90% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 3.0 3.25607064018 92% => OK
Article: 10.0 8.23620309051 121% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 3.0 1.51434878587 198% => OK
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 11.0 13.0662251656 84% => Need more sentences. Double check the format of sentences, make sure there is a space between two sentences, or have enough periods. And also check the lengths of sentences, maybe they are too long.
Sentence length: 25.0 21.2450331126 118% => OK
Sentence length SD: 52.059882875 49.2860985944 106% => OK
Chars per sentence: 122.363636364 110.228320801 111% => OK
Words per sentence: 25.3636363636 21.698381199 117% => OK
Discourse Markers: 9.18181818182 7.06452816374 130% => 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 : 2.0 4.45695364238 45% => More negative sentences wanted.
Sentences with neutral sentiment: 6.0 4.27373068433 140% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.192554698905 0.272083759551 71% => OK
Sentence topic coherence: 0.0763752623664 0.0996497079465 77% => OK
Sentence topic coherence SD: 0.0700226306445 0.0662205650399 106% => OK
Paragraph topic coherence: 0.123026994169 0.162205337803 76% => OK
Paragraph topic coherence SD: 0.0925842909707 0.0443174109184 209% => More connections among paragraphs wanted.
Essay readability:
automated_readability_index: 14.0 13.3589403974 105% => OK
flesch_reading_ease: 63.02 53.8541721854 117% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 10.7 11.0289183223 97% => OK
coleman_liau_index: 10.97 12.2367328918 90% => OK
dale_chall_readability_score: 8.44 8.42419426049 100% => OK
difficult_words: 63.0 63.6247240618 99% => OK
linsear_write_formula: 17.5 10.7273730684 163% => OK
gunning_fog: 12.0 10.498013245 114% => OK
text_standard: 11.0 11.2008830022 98% => OK
What are above readability scores?
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Rates: 78.3333333333 out of 100
Scores by essay e-grader: 23.5 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.