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 article discuses the Agnostids, a group of marine animals who became extinct 450 million years ago, and the way they lived which is a controversy topic among researchers since the fossil formation does not inform them about it. The author proposes three possible theories about how they may have lived. However, the professor refutes each of these theories.
First, the passage claims that there exist other primitive arthropods who were free-swimming predators and they may have lived that way since there were plenty of smaller organisms on which they may have preyed. However, the lecturer claims that in order to be a predators they had to have well-developed eyes or other types of sensory organs which was not observable in the fossils.
Second, the reading states that since there are other types of primitive arthropods who are living on the seafloor feeding on dead animals, the Agnostides may have been seafloor dwellers as well. However, the professor avers that the dwellers cannot spread in large areas because of their slow dislocation. They are commonly spreaded in small areas where they have originate, however, Agnostides were living in multiple areas.
Third, the article claims that they may have lived like parasites, who live on larger animals. There are other species of arthropods and Agnostids might have been similar and living on primitive fish. The professor avers that the there is a limitation in the population of parasites and otherwise they will kill the host animal. Vast amounts of fossils however suggests that there were abundant in the sea, hence could not be parasites.
| Post date | Users | Rates | Link to Content |
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| 2020-01-24 | jewel | 76 | view |
| 2020-01-03 | jason_linnil | 76 | view |
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| 2019-12-04 | shatealabo1110 | 70 | view |
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Grammar and spelling errors:
Line 3, column 262, Rule ID: A_PLURAL[1]
Message: Don't use indefinite articles with plural words. Did you mean 'a predator' or simply 'predators'?
Suggestion: a predator; predators
...the lecturer claims that in order to be a predators they had to have well-developed eyes or...
^^^^^^^^^^^
Line 5, column 366, Rule ID: HAVE_PART_AGREEMENT[1]
Message: Use past participle here: 'originated'.
Suggestion: originated
...spreaded in small areas where they have originate, however, Agnostides were living in mul...
^^^^^^^^^
Transition Words or Phrases used:
first, hence, however, may, second, so, third, well
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 15.0 10.4613686534 143% => OK
Auxiliary verbs: 9.0 5.04856512141 178% => OK
Conjunction : 6.0 7.30242825607 82% => OK
Relative clauses : 16.0 12.0772626932 132% => OK
Pronoun: 21.0 22.412803532 94% => OK
Preposition: 30.0 30.3222958057 99% => OK
Nominalization: 4.0 5.01324503311 80% => OK
Performance on vocabulary words:
No of characters: 1359.0 1373.03311258 99% => OK
No of words: 263.0 270.72406181 97% => OK
Chars per words: 5.16730038023 5.08290768461 102% => OK
Fourth root words length: 4.02706775958 4.04702891845 100% => OK
Word Length SD: 2.49570464754 2.5805825403 97% => OK
Unique words: 141.0 145.348785872 97% => OK
Unique words percentage: 0.536121673004 0.540411800872 99% => OK
syllable_count: 424.8 419.366225166 101% => 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: 11.0 8.23620309051 134% => OK
Subordination: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 1.0 1.51434878587 66% => OK
Preposition: 0.0 2.5761589404 0% => More preposition wanted as sentence beginning.
Performance on sentences:
How many sentences: 12.0 13.0662251656 92% => OK
Sentence length: 21.0 21.2450331126 99% => OK
Sentence length SD: 53.5721216886 49.2860985944 109% => OK
Chars per sentence: 113.25 110.228320801 103% => OK
Words per sentence: 21.9166666667 21.698381199 101% => OK
Discourse Markers: 4.25 7.06452816374 60% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 2.0 4.19205298013 48% => OK
Sentences with positive sentiment : 1.0 4.33554083885 23% => More positive sentences wanted.
Sentences with negative sentiment : 3.0 4.45695364238 67% => 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: 0.186680903057 0.272083759551 69% => OK
Sentence topic coherence: 0.069538434411 0.0996497079465 70% => OK
Sentence topic coherence SD: 0.0658768424416 0.0662205650399 99% => OK
Paragraph topic coherence: 0.120932215638 0.162205337803 75% => OK
Paragraph topic coherence SD: 0.0356672874994 0.0443174109184 80% => OK
Essay readability:
automated_readability_index: 13.9 13.3589403974 104% => OK
flesch_reading_ease: 50.16 53.8541721854 93% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 11.5 11.0289183223 104% => OK
coleman_liau_index: 12.71 12.2367328918 104% => OK
dale_chall_readability_score: 8.7 8.42419426049 103% => OK
difficult_words: 67.0 63.6247240618 105% => OK
linsear_write_formula: 9.0 10.7273730684 84% => OK
gunning_fog: 10.4 10.498013245 99% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
---------------------
Rates: 85.0 out of 100
Scores by essay e-grader: 25.5 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.