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.
The reading passage discusses agnostids, which were a group of marine animals that became extinct about 450 million years ago. The author proposes three theories to show agnostids' possible behaviors. However, the speaker holds these arguments questionable.
First of all, the article claims that agnostids may have been free-swimming predators. Nevertheless, the lecture points out that to be free-swimming predators, their eyes must be good so that they can track the prey. In contrast, agnostids' eyes are poor, showing by the fossil. If agnostids are really free-swimming predators, they have to own other special organs to help them as the predators. Unfortunately, there is no evidence to show that.
Secondly, the writer states that agnostids may have dwelled on the seafloor and scavenge dead organisms or graze on bacteria. On the other hand, the lecturer argues that most creatures living on the seafloor usually assemble on the relatively small place because they are moving slowly. Nonetheless, the evidence shows that the agnostids occupy many areas. In other words, they could move fast.
Furthermore, the author says agnostids may be parasites. However, the speaker contends that the populations of parasites usually are limited because the host organisms cannot sustain too many parasites parasitize on them. Yet, according to the findings, the agnostids consists of large populations.
To sum up, all the points mentioned in the reading passages are not plausible according to the speaker.
Transition Words or Phrases used:
first, furthermore, however, if, may, nevertheless, nonetheless, really, second, secondly, so, well, in contrast, first of all, in other words, to sum up, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 11.0 10.4613686534 105% => OK
Auxiliary verbs: 7.0 5.04856512141 139% => OK
Conjunction : 2.0 7.30242825607 27% => More conjunction wanted.
Relative clauses : 10.0 12.0772626932 83% => OK
Pronoun: 17.0 22.412803532 76% => OK
Preposition: 25.0 30.3222958057 82% => OK
Nominalization: 2.0 5.01324503311 40% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1284.0 1373.03311258 94% => OK
No of words: 233.0 270.72406181 86% => More content wanted.
Chars per words: 5.51072961373 5.08290768461 108% => OK
Fourth root words length: 3.90696013833 4.04702891845 97% => OK
Word Length SD: 2.84013828107 2.5805825403 110% => OK
Unique words: 144.0 145.348785872 99% => OK
Unique words percentage: 0.618025751073 0.540411800872 114% => OK
syllable_count: 384.3 419.366225166 92% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 3.0 3.25607064018 92% => OK
Article: 11.0 8.23620309051 134% => OK
Subordination: 1.0 1.25165562914 80% => OK
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 5.0 2.5761589404 194% => OK
Performance on sentences:
How many sentences: 16.0 13.0662251656 122% => OK
Sentence length: 14.0 21.2450331126 66% => The Avg. Sentence Length is relatively short.
Sentence length SD: 38.6235335482 49.2860985944 78% => OK
Chars per sentence: 80.25 110.228320801 73% => OK
Words per sentence: 14.5625 21.698381199 67% => OK
Discourse Markers: 10.75 7.06452816374 152% => OK
Paragraphs: 5.0 4.09492273731 122% => OK
Language errors: 0.0 4.19205298013 0% => OK
Sentences with positive sentiment : 3.0 4.33554083885 69% => OK
Sentences with negative sentiment : 5.0 4.45695364238 112% => 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: 0.24948849038 0.272083759551 92% => OK
Sentence topic coherence: 0.0780654722114 0.0996497079465 78% => OK
Sentence topic coherence SD: 0.0811239227396 0.0662205650399 123% => OK
Paragraph topic coherence: 0.121252007432 0.162205337803 75% => OK
Paragraph topic coherence SD: 0.0886786025298 0.0443174109184 200% => More connections among paragraphs wanted.
Essay readability:
automated_readability_index: 11.8 13.3589403974 88% => Automated_readability_index is low.
flesch_reading_ease: 57.27 53.8541721854 106% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 8.8 11.0289183223 80% => OK
coleman_liau_index: 14.09 12.2367328918 115% => OK
dale_chall_readability_score: 8.46 8.42419426049 100% => OK
difficult_words: 61.0 63.6247240618 96% => OK
linsear_write_formula: 6.5 10.7273730684 61% => OK
gunning_fog: 7.6 10.498013245 72% => OK
text_standard: 9.0 11.2008830022 80% => 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.