Agnostids were a group of marine animals that became extinct about 450 million years ago. Agnostid fossils can be found in rocks in many areas around the world. From the fossil remains, we know that agnostids were primitive arthropods-relatives of modern-day insects. However, the fossil information does not allow paleontologists to determine with certainty what agnostids ate or how they behaved. There are several different theories about how agnostids may have lived.
Free-Swimming Predators
First, the agnostids may have been free-swimming predators that hunted smaller animals. It is known that other types of primitive arthropods were strong swimmers and active predators, so it is reasonable that the agnostids may have lived that way as well And while the agnostids were small, sometimes just six millimeters long, there were plenty of smaller organisms in the ancient ocean for them to prey on.
Seafloor Dwellers
Second, they may have dwelled on the seafloor. Again, there are examples of other types of primitive arthropods living this way, so it is possible that agnostids did too. On the seafloor they would have survived by scavenging dead organisms or by grazing on bacteria.
Parasites
Third, there is the possibility that the agnostids were parasites, living on and feeding off larger organisms. One reason that this seems possible is that there are many species of modern-day arthropods that exist as parasites, such as fleas, ticks, and mites. The agnostids might have lived on primitive fish or even on other, larger arthropods.
Both the article and the professor discuss about how agnostids, a group of marine animals which became extinct about 450 million years ago, may have lived. The writer puts forward three
hypotheses, which are contradicted by the following passage.
Firstly, the writer claims that agnostids may be strong swimmers and active predators. On the contrary, the speaker refutes the argument by stating that all arthropods have highly-developed
eyes, because vision plays an important role in tracking preys for predators. However, agnostids only had tiny poor eyes and some of them were even blind, which suggests that they can't be predators.
Secondly, the writer believes that agnostids may be dwellers on the seafloor. Nevertheless, the speaker explains that marine animals living on the seafloor usually can't move fast, and they
always live within a localized area. Agnostids, however, were able to inhabited multiple geographic areas that spread across a large distance, showing that they had ability to move fast. So they can't be seafloor dwellers.
Thirdly, the writer says that agnostids may also be parasites living on and feeding off larger organisms such as primitive fish and larger arthropods. Again, the speaker disagrees by pointing out that the population of parasites can't be large since too many parasites can kill the host organism they live on. But fossils of agnostids suggested they had a large population before. As a result, they couldn't be parasites.
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| 2023-09-05 | YasamanEsml | 86 | view |
| 2023-06-19 | Vivian Chang | 76 | view |
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| 2023-01-30 | reza_fattahi | 75 | view |
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Grammar and spelling errors:
Line 5, column 181, Rule ID: CANT[1]
Message: Did you mean 'can't' or 'cannot'?
Suggestion: can't; cannot
...re even blind, which suggests that they cant be predators. Secondly, the writer b...
^^^^
Line 7, column 165, Rule ID: CANT[1]
Message: Did you mean 'can't' or 'cannot'?
Suggestion: can't; cannot
... animals living on the seafloor usually cant move fast, and they always live within...
^^^^
Line 8, column 196, Rule ID: CANT[1]
Message: Did you mean 'can't' or 'cannot'?
Suggestion: can't; cannot
... they had ability to move fast. So they cant be seafloor dwellers. Thirdly, the w...
^^^^
Line 10, column 230, Rule ID: CANT[1]
Message: Did you mean 'can't' or 'cannot'?
Suggestion: can't; cannot
...ng out that the population of parasites cant be large since too many parasites can k...
^^^^
Line 10, column 399, Rule ID: EN_CONTRACTION_SPELLING
Message: Possible spelling mistake found
Suggestion: couldn't
...ge population before. As a result, they couldnt be parasites.
^^^^^^^
Transition Words or Phrases used:
also, but, first, firstly, however, may, nevertheless, second, secondly, so, third, thirdly, well, such as, as a result, on the contrary
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 10.0 10.4613686534 96% => OK
Auxiliary verbs: 5.0 5.04856512141 99% => OK
Conjunction : 7.0 7.30242825607 96% => OK
Relative clauses : 12.0 12.0772626932 99% => OK
Pronoun: 17.0 22.412803532 76% => OK
Preposition: 23.0 30.3222958057 76% => OK
Nominalization: 4.0 5.01324503311 80% => OK
Performance on vocabulary words:
No of characters: 1252.0 1373.03311258 91% => OK
No of words: 233.0 270.72406181 86% => More content wanted.
Chars per words: 5.37339055794 5.08290768461 106% => OK
Fourth root words length: 3.90696013833 4.04702891845 97% => OK
Word Length SD: 2.66801635304 2.5805825403 103% => OK
Unique words: 141.0 145.348785872 97% => OK
Unique words percentage: 0.605150214592 0.540411800872 112% => OK
syllable_count: 378.0 419.366225166 90% => 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: 8.0 8.23620309051 97% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 2.0 1.51434878587 132% => OK
Preposition: 1.0 2.5761589404 39% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 17.0 21.2450331126 80% => The Avg. Sentence Length is relatively short.
Sentence length SD: 46.6796966875 49.2860985944 95% => OK
Chars per sentence: 96.3076923077 110.228320801 87% => OK
Words per sentence: 17.9230769231 21.698381199 83% => OK
Discourse Markers: 10.4615384615 7.06452816374 148% => OK
Paragraphs: 7.0 4.09492273731 171% => Less paragraphs wanted.
Language errors: 5.0 4.19205298013 119% => OK
Sentences with positive sentiment : 4.0 4.33554083885 92% => OK
Sentences with negative sentiment : 4.0 4.45695364238 90% => OK
Sentences with neutral sentiment: 5.0 4.27373068433 117% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.24173875121 0.272083759551 89% => OK
Sentence topic coherence: 0.0824031400265 0.0996497079465 83% => OK
Sentence topic coherence SD: 0.0595555973821 0.0662205650399 90% => OK
Paragraph topic coherence: 0.100493280849 0.162205337803 62% => OK
Paragraph topic coherence SD: 0.0557323216534 0.0443174109184 126% => OK
Essay readability:
automated_readability_index: 12.8 13.3589403974 96% => OK
flesch_reading_ease: 54.22 53.8541721854 101% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 9.9 11.0289183223 90% => OK
coleman_liau_index: 13.57 12.2367328918 111% => OK
dale_chall_readability_score: 9.02 8.42419426049 107% => OK
difficult_words: 67.0 63.6247240618 105% => OK
linsear_write_formula: 10.5 10.7273730684 98% => OK
gunning_fog: 8.8 10.498013245 84% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
---------------------
Maximum four paragraphs wanted.
Rates: 75.0 out of 100
Scores by essay e-grader: 22.5 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.