"Two studies of amphibians in Xanadu National Park confirm a significant decline in the numbers of amphibians. In 1975 there were seven species of amphibians in the park, and there were abundant numbers of each species. However, in 2002 only four species of amphibians were observed in the park, and the numbers of each species were drastically reduced. One proposed explanation is that the decline was caused by the introduction of trout into the park's waters, which began in 1975. (Trout are known to eat amphibian eggs.)"
Write a response in which you discuss one or more alternative explanations that could rival the proposed explanation and explain how your explanation(s) can plausibly account for the facts presented in the argument.
The author offers one explanation about the decline of amphibians in Xanadu National Park, according to which trouts are responsible for this event. In what follows, I shall offer a number of rival explanations.
The explanation mentioned by the author seems convincing at first glance. Indeed, trouts were first introduced in the park in 1975, when the population of amphibians was great. It is easy to suppose that the decline of those amphibians is due to trout: otherwise, it would have happened before 1975. However, this hypothesis would have been more compelling if other information had been provided. First, the two studies on which the explanation of the author is based do not explain what kinds of trouts were introduced. Of course, trouts are generally known as predators of amphibians. However, what if the trouts that were introduced had not been predators of amphibians? It is possible that animal belonging to the same species show different behaviours. Another question that needs to be answered concerns the number of trouts that were introduced. If that number had been low, it would have been difficult for the trouts to eat a great number of eggs of amphibians. Of couse, some people may object by arguing that since there was a suitable environment for trouts – there was no scarcity of food – the number of trouts increased. However, there is also the possibility that the rate of the increase of trouts was not so high. After all, 35 years is a short time for a species to completely replace another one.
It is worth considering other rival explanations. First, the decline of amphibians can be caused by the pollution of the water. Perhaps, the amphibians in the park could not tolerate certain substances that were damping in the water where they swam. Of course, some people may object that if this had been the case, other species would have been declined. However, we do not know if this was the case: the two studies only concern the population of amphibians. Second, it is possible that the substances in the water damaged only amphibians. Incidentally, this explanation is able to explain why the population of amphibians dramatically reduced in thirty years.
Another possible explanation is the presence of other predators. We can suppose that after introducing trouts the National Park also introduced a different predator of amphibians, which was more effective to capture eggs than trouts.
What about if the policy of National Park changed after 1975: perhaps they decided to reduce the temperature of water since they were at risk of bankruptcy. By reducing the temperature of the water, it was more difficult for baby amphibians to grow up.
To sum up, the author mentions an explanation which is seemingly convincing. However, it has different problems and other putative explanations – from those about the presence of other predators to those about a change of the temperature of water and pollution – seems to be suitable. In order to enhance the explanation mentioned, the author should provide other pieces of information and refute the other theories.
Comments
Essay evaluation report
Attribute Value Ideal
Final score: 3.5 out of 6
Category: Satisfactory Excellent
No. of Grammatical Errors: 0 2
No. of Spelling Errors: 0 2
No. of Sentences: 29 15
No. of Words: 510 350
No. of Characters: 2521 1500
No. of Different Words: 205 200
Fourth Root of Number of Words: 4.752 4.7
Average Word Length: 4.943 4.6
Word Length SD: 2.727 2.4
No. of Words greater than 5 chars: 175 100
No. of Words greater than 6 chars: 132 80
No. of Words greater than 7 chars: 97 40
No. of Words greater than 8 chars: 72 20
Use of Passive Voice (%): 0 0
Avg. Sentence Length: 17.586 21.0
Sentence Length SD: 6.077 7.5
Use of Discourse Markers (%): 0.655 0.12
Sentence-Text Coherence: 0.298 0.35
Sentence-Para Coherence: 0.481 0.50
Sentence-Sentence Coherence: 0.083 0.07
Number of Paragraphs: 6 5
Grammar and spelling errors:
Line 3, column 1104, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...trouts – there was no scarcity of food – the number of trouts increased. However,...
^^
Transition Words or Phrases used:
also, first, however, if, incidentally, may, second, so, after all, of course, to sum up
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 36.0 19.6327345309 183% => OK
Auxiliary verbs: 11.0 12.9520958084 85% => OK
Conjunction : 3.0 11.1786427146 27% => More conjunction wanted.
Relative clauses : 18.0 13.6137724551 132% => OK
Pronoun: 34.0 28.8173652695 118% => OK
Preposition: 77.0 55.5748502994 139% => OK
Nominalization: 19.0 16.3942115768 116% => OK
Performance on vocabulary words:
No of characters: 2610.0 2260.96107784 115% => OK
No of words: 514.0 441.139720559 117% => OK
Chars per words: 5.07782101167 5.12650576532 99% => OK
Fourth root words length: 4.76146701107 4.56307096286 104% => OK
Word Length SD: 2.81574982234 2.78398813304 101% => OK
Unique words: 214.0 204.123752495 105% => OK
Unique words percentage: 0.416342412451 0.468620217663 89% => More unique words wanted or less content wanted.
syllable_count: 807.3 705.55239521 114% => OK
avg_syllables_per_word: 1.6 1.59920159681 100% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 13.0 4.96107784431 262% => Less pronouns wanted as sentence beginning.
Article: 7.0 8.76447105788 80% => OK
Subordination: 3.0 2.70958083832 111% => OK
Conjunction: 0.0 1.67365269461 0% => OK
Preposition: 9.0 4.22255489022 213% => Less preposition wanted as sentence beginnings.
Performance on sentences:
How many sentences: 29.0 19.7664670659 147% => OK
Sentence length: 17.0 22.8473053892 74% => The Avg. Sentence Length is relatively short.
Sentence length SD: 36.6106551614 57.8364921388 63% => OK
Chars per sentence: 90.0 119.503703932 75% => OK
Words per sentence: 17.724137931 23.324526521 76% => OK
Discourse Markers: 3.03448275862 5.70786347227 53% => More transition words/phrases wanted.
Paragraphs: 6.0 5.15768463074 116% => OK
Language errors: 1.0 5.25449101796 19% => OK
Sentences with positive sentiment : 12.0 8.20758483034 146% => OK
Sentences with negative sentiment : 6.0 6.88822355289 87% => OK
Sentences with neutral sentiment: 11.0 4.67664670659 235% => Less facts, knowledge or examples wanted.
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.24611276336 0.218282227539 113% => OK
Sentence topic coherence: 0.0697658977399 0.0743258471296 94% => OK
Sentence topic coherence SD: 0.0585402191324 0.0701772020484 83% => OK
Paragraph topic coherence: 0.129207007339 0.128457276422 101% => OK
Paragraph topic coherence SD: 0.0705646551943 0.0628817314937 112% => OK
Essay readability:
automated_readability_index: 11.4 14.3799401198 79% => Automated_readability_index is low.
flesch_reading_ease: 54.22 48.3550499002 112% => OK
smog_index: 8.8 7.1628742515 123% => OK
flesch_kincaid_grade: 9.9 12.197005988 81% => OK
coleman_liau_index: 11.89 12.5979740519 94% => OK
dale_chall_readability_score: 7.34 8.32208582834 88% => OK
difficult_words: 93.0 98.500998004 94% => OK
linsear_write_formula: 8.5 12.3882235529 69% => OK
gunning_fog: 8.8 11.1389221557 79% => OK
text_standard: 9.0 11.9071856287 76% => OK
What are above readability scores?
---------------------
Rates: 58.33 out of 100
Scores by essay e-grader: 3.5 Out of 6
---------------------
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.