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 reading passage and lecture discuss whether living theories about agnostids are right or not. The former provides three evidence regarding these, but the later refutes each of these points.
first of all, the author of the passage claims that the agnostids might capture small animals while swimming in the sea, even small agnostids might able to prey a lot of small species. However, the lecture contends that free-swimming predators need large well developed eyes, which were absent in the agnostids. Therefore, their poor visions ruled out this idea as there was no further evidence of presence of any other sensory organisms, which they could use instead of eyesights.
Secondly, the text asserts that agnostids might live in the seafloor, where they could find available dead organisms and bacteria to survive. In contrat, the listening counters that seafloor dwellers do not have the ability to move faster and they tend to live in one single places throughout their lifetime. But agnostids originated and habitated in multiple places and could move with high speed, which were very unusual to the seafloors residence.
In third, the reading passage states that the agnostids might be parasites and lived on other ancient fish or big arthropods. On the other hand, the lecturer mentions that to be parasites, there might be the limit of the overall popoulation as larger population might kill the whole host organisms. Hence, the fossils records supported that the agnostids had abundant populations, which were the opposite of being parasites.
| Post date | Users | Rates | Link to Content |
|---|---|---|---|
| 2023-09-05 | YasamanEsml | 86 | view |
| 2023-06-19 | Vivian Chang | 76 | view |
| 2023-02-07 | reza_fattahi | 73 | view |
| 2023-01-30 | reza_fattahi | 86 | view |
| 2023-01-30 | reza_fattahi | 75 | view |
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Grammar and spelling errors:
Line 3, column 1, Rule ID: UPPERCASE_SENTENCE_START
Message: This sentence does not start with an uppercase letter
Suggestion: First
... later refutes each of these points. first of all, the author of the passage claim...
^^^^^
Line 5, column 431, Rule ID: POSSESIVE_APOSTROPHE[2]
Message: Possible typo: apostrophe is missing. Did you mean 'seafloors'' or 'seafloor's'?
Suggestion: seafloors'; seafloor's
...h speed, which were very unusual to the seafloors residence. In third, the reading pas...
^^^^^^^^^
Transition Words or Phrases used:
but, first, hence, however, if, regarding, second, secondly, so, therefore, third, well, while, first of all, on the other hand
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 9.0 10.4613686534 86% => OK
Auxiliary verbs: 10.0 5.04856512141 198% => OK
Conjunction : 10.0 7.30242825607 137% => OK
Relative clauses : 12.0 12.0772626932 99% => OK
Pronoun: 15.0 22.412803532 67% => OK
Preposition: 30.0 30.3222958057 99% => OK
Nominalization: 6.0 5.01324503311 120% => OK
Performance on vocabulary words:
No of characters: 1319.0 1373.03311258 96% => OK
No of words: 250.0 270.72406181 92% => More content wanted.
Chars per words: 5.276 5.08290768461 104% => OK
Fourth root words length: 3.97635364384 4.04702891845 98% => OK
Word Length SD: 2.51396420022 2.5805825403 97% => OK
Unique words: 157.0 145.348785872 108% => OK
Unique words percentage: 0.628 0.540411800872 116% => OK
syllable_count: 398.7 419.366225166 95% => 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: 0.0 1.25165562914 0% => More adverbial clause wanted.
Conjunction: 2.0 1.51434878587 132% => OK
Preposition: 3.0 2.5761589404 116% => OK
Performance on sentences:
How many sentences: 11.0 13.0662251656 84% => Need more sentences. Double check the format of sentences, make sure there is a space between two sentences, or have enough periods. And also check the lengths of sentences, maybe they are too long.
Sentence length: 22.0 21.2450331126 104% => OK
Sentence length SD: 27.9459336328 49.2860985944 57% => The essay contains lots of sentences with the similar length. More sentence varieties wanted.
Chars per sentence: 119.909090909 110.228320801 109% => OK
Words per sentence: 22.7272727273 21.698381199 105% => OK
Discourse Markers: 11.5454545455 7.06452816374 163% => OK
Paragraphs: 4.0 4.09492273731 98% => OK
Language errors: 2.0 4.19205298013 48% => OK
Sentences with positive sentiment : 2.0 4.33554083885 46% => More positive sentences wanted.
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: 0.170903247032 0.272083759551 63% => OK
Sentence topic coherence: 0.0673478230706 0.0996497079465 68% => OK
Sentence topic coherence SD: 0.0594962596556 0.0662205650399 90% => OK
Paragraph topic coherence: 0.0981860716473 0.162205337803 61% => OK
Paragraph topic coherence SD: 0.0348426573561 0.0443174109184 79% => OK
Essay readability:
automated_readability_index: 14.8 13.3589403974 111% => OK
flesch_reading_ease: 49.15 53.8541721854 91% => OK
smog_index: 8.8 5.55761589404 158% => OK
flesch_kincaid_grade: 11.9 11.0289183223 108% => OK
coleman_liau_index: 13.64 12.2367328918 111% => OK
dale_chall_readability_score: 9.28 8.42419426049 110% => OK
difficult_words: 72.0 63.6247240618 113% => OK
linsear_write_formula: 9.0 10.7273730684 84% => OK
gunning_fog: 10.8 10.498013245 103% => OK
text_standard: 9.0 11.2008830022 80% => OK
What are above readability scores?
---------------------
Rates: 90.0 out of 100
Scores by essay e-grader: 27.0 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.