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 passage and the lecture hypothesize of the possible theories about how agnodtids ate or behaved. The author provids three theories, but the lecturer contradicts each one of them.
First, the author claims that agnostids may have been free swimming predators, because there is evidence that other types of arthropods were infact predators. However, the pforessor casts doubts on this theory by pointing out that all of these arthropods had big eyes, because vision is very important for hunting, and this big eyes help predators to hunt. In contrast it is found out that agnostids had small eyes, with poor vision, which can't be used for hunting. Moreover, no other features of agnostids could have helped them to hunt. Considering this argument agnostids being predators is contradicted.
Second, the passage conducts agnostids to be seafloor dwellers. However, the professor rebuts this idea by observing geographical area which agnostids spread on. He elaborates that, usually seafloor dwellers move slowly and stay on a local area, neverthless, evidences shows that agnostids spread on a large geographically large area, and this shows that they should have been very fast moving, which is very unusual for seafloor dwellers.
Third, the reading comes up with the idea on agnostids being parasites, but the professor reckons that considering large population of them this seems impossible. Furthermore, he elaborates that to be able to feed from larger organisms, population should be limited, but there is evidence of very large population of agnostids. Considering this population this theory is about refuted.
| Post date | Users | Rates | Link to Content |
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| 2020-01-24 | jewel | 76 | view |
| 2020-01-03 | jason_linnil | 76 | view |
| 2019-12-20 | jewel | 80 | view |
| 2019-12-04 | shatealabo1110 | 70 | view |
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Grammar and spelling errors:
Line 2, column 1, Rule ID: WHITESPACE_RULE
Message: Possible typo: you repeated a whitespace
Suggestion:
...lecturer contradicts each one of them. First, the author claims that agnostids...
^^^
Line 3, column 362, Rule ID: SENT_START_CONJUNCTIVE_LINKING_ADVERB_COMMA[2]
Message: Did you forget a comma after a conjunctive/linking adverb?
Suggestion: contrast,
...his big eyes help predators to hunt. In contrast it is found out that agnostids had smal...
^^^^^^^^
Line 3, column 442, Rule ID: CANT[1]
Message: Did you mean 'can't' or 'cannot'?
Suggestion: can't; cannot
...had small eyes, with poor vision, which cant be used for hunting. Moreover, no other...
^^^^
Transition Words or Phrases used:
but, first, furthermore, however, may, moreover, second, so, third, well, in contrast
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 16.0 10.4613686534 153% => OK
Auxiliary verbs: 4.0 5.04856512141 79% => OK
Conjunction : 8.0 7.30242825607 110% => OK
Relative clauses : 12.0 12.0772626932 99% => OK
Pronoun: 25.0 22.412803532 112% => OK
Preposition: 32.0 30.3222958057 106% => OK
Nominalization: 7.0 5.01324503311 140% => OK
Performance on vocabulary words:
No of characters: 1382.0 1373.03311258 101% => OK
No of words: 254.0 270.72406181 94% => More content wanted.
Chars per words: 5.44094488189 5.08290768461 107% => OK
Fourth root words length: 3.99216450694 4.04702891845 99% => OK
Word Length SD: 2.7694828651 2.5805825403 107% => OK
Unique words: 144.0 145.348785872 99% => OK
Unique words percentage: 0.566929133858 0.540411800872 105% => OK
syllable_count: 413.1 419.366225166 99% => OK
avg_syllables_per_word: 1.6 1.55342163355 103% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 2.0 3.25607064018 61% => OK
Article: 6.0 8.23620309051 73% => OK
Subordination: 2.0 1.25165562914 160% => OK
Conjunction: 5.0 1.51434878587 330% => Less conjunction wanted as sentence beginning.
Preposition: 4.0 2.5761589404 155% => OK
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 19.0 21.2450331126 89% => OK
Sentence length SD: 62.1303268525 49.2860985944 126% => OK
Chars per sentence: 106.307692308 110.228320801 96% => OK
Words per sentence: 19.5384615385 21.698381199 90% => OK
Discourse Markers: 6.53846153846 7.06452816374 93% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 3.0 4.19205298013 72% => OK
Sentences with positive sentiment : 2.0 4.33554083885 46% => More positive sentences wanted.
Sentences with negative sentiment : 7.0 4.45695364238 157% => OK
Sentences with neutral sentiment: 4.0 4.27373068433 94% => OK
What are sentences with positive/Negative/neutral sentiment?
Coherence and Cohesion:
Essay topic to essay body coherence: 0.173695015362 0.272083759551 64% => OK
Sentence topic coherence: 0.0717085152824 0.0996497079465 72% => OK
Sentence topic coherence SD: 0.0440318937548 0.0662205650399 66% => OK
Paragraph topic coherence: 0.0930601961059 0.162205337803 57% => OK
Paragraph topic coherence SD: 0.0504743685197 0.0443174109184 114% => OK
Essay readability:
automated_readability_index: 14.0 13.3589403974 105% => OK
flesch_reading_ease: 52.19 53.8541721854 97% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 10.7 11.0289183223 97% => OK
coleman_liau_index: 14.27 12.2367328918 117% => OK
dale_chall_readability_score: 8.56 8.42419426049 102% => OK
difficult_words: 64.0 63.6247240618 101% => OK
linsear_write_formula: 9.0 10.7273730684 84% => OK
gunning_fog: 9.6 10.498013245 91% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
---------------------
Rates: 80.0 out of 100
Scores by essay e-grader: 24.0 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.