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 and lecture both deal with how agnostids my have lived. Whilst the author proposes three possible hypotheses and provides evidence to support them, the lecturer contradicts his arguments respectively.
First, the author states that agnostids may have lived as strong swimmers and active predators, and there are plenty of smaller organisms in the ancient ocean for them to hunt. In contrast, the professor argues that predators usually have large eyes and well developed vision, while agnostids have tiny eyes and poor visions, and some even are blind. Furthermore, she also rule out the possibility that agnostids may use other sensory organs instead of eyes, as there is no evidence has been obtained so far.
Second, according to the article, agnostids might live on the seafloor, and feed on dead organisms or bacteria. However, the lecturer again questions this argument by pointing out that agnostids live in multiple geological areas, indicating that they may move very fast. This is on contrary to seafloor dwellers, which usually move very slow and live in very small geological area.
Last, the author posits that agnostids could be parasites and lived on fish or other larger organisms because many types of arthropods live this way. As opposed to the writer, the speaker mentions that the population of parasites is often very small, so they would not kill the hosts. Unlike parasites, agnostids lived in large group.
As we can see, the author and lecturer hold very different views on possible ways that agnostids may have lived.
Comments
Essay evaluations by e-grader
Grammar and spelling errors:
Line 1, column 93, Rule ID: CD_NN[1]
Message: Possible agreement error. The noun 'hypothesis' seems to be countable, so consider using: 'hypotheses', 'hypothesises'.
Suggestion: hypotheses; hypothesises
...ilst the author proposed three possible hypothesis that agnostids my have lived, the lectu...
^^^^^^^^^^
Line 3, column 492, Rule ID: HE_VERB_AGR[3]
Message: The pronoun 'she' must be used with a third-person verb: 'rules'.
Suggestion: rules
...e even are blind. Furthermore, she also rule out the possibility that agnostids may ...
^^^^
Transition Words or Phrases used:
also, first, furthermore, however, if, may, second, so, therefore, well, while, in contrast
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 10.0 10.4613686534 96% => OK
Auxiliary verbs: 8.0 5.04856512141 158% => OK
Conjunction : 9.0 7.30242825607 123% => OK
Relative clauses : 11.0 12.0772626932 91% => OK
Pronoun: 19.0 22.412803532 85% => OK
Preposition: 27.0 30.3222958057 89% => OK
Nominalization: 3.0 5.01324503311 60% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1417.0 1373.03311258 103% => OK
No of words: 268.0 270.72406181 99% => OK
Chars per words: 5.28731343284 5.08290768461 104% => OK
Fourth root words length: 4.04607285448 4.04702891845 100% => OK
Word Length SD: 2.57717535561 2.5805825403 100% => OK
Unique words: 153.0 145.348785872 105% => OK
Unique words percentage: 0.570895522388 0.540411800872 106% => OK
syllable_count: 442.8 419.366225166 106% => OK
avg_syllables_per_word: 1.7 1.55342163355 109% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 3.0 3.25607064018 92% => OK
Article: 8.0 8.23620309051 97% => OK
Subordination: 4.0 1.25165562914 320% => Less adverbial clause wanted.
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 3.0 2.5761589404 116% => OK
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 65.3465952808 49.2860985944 133% => OK
Chars per sentence: 109.0 110.228320801 99% => OK
Words per sentence: 20.6153846154 21.698381199 95% => OK
Discourse Markers: 7.0 7.06452816374 99% => OK
Paragraphs: 5.0 4.09492273731 122% => 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 : 7.0 4.45695364238 157% => 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: 0.165641031514 0.272083759551 61% => OK
Sentence topic coherence: 0.0654006831743 0.0996497079465 66% => OK
Sentence topic coherence SD: 0.0496375463029 0.0662205650399 75% => OK
Paragraph topic coherence: 0.0977483724267 0.162205337803 60% => OK
Paragraph topic coherence SD: 0.0296654785055 0.0443174109184 67% => OK
Essay readability:
automated_readability_index: 13.8 13.3589403974 103% => OK
flesch_reading_ease: 42.72 53.8541721854 79% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 12.3 11.0289183223 112% => OK
coleman_liau_index: 13.4 12.2367328918 110% => OK
dale_chall_readability_score: 8.75 8.42419426049 104% => OK
difficult_words: 70.0 63.6247240618 110% => OK
linsear_write_formula: 13.5 10.7273730684 126% => OK
gunning_fog: 10.0 10.498013245 95% => OK
text_standard: 14.0 11.2008830022 125% => OK
What are above readability scores?
---------------------
Rates: 80.0 out of 100
Scores by essay e-grader: 24.0 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.
Grammar and spelling errors:
Line 1, column 93, Rule ID: CD_NN[1]
Message: Possible agreement error. The noun 'hypothesis' seems to be countable, so consider using: 'hypotheses', 'hypothesises'.
Suggestion: hypotheses; hypothesises
...ilst the author proposed three possible hypothesis that agnostids my have lived, the lectu...
^^^^^^^^^^
Line 3, column 492, Rule ID: HE_VERB_AGR[3]
Message: The pronoun 'she' must be used with a third-person verb: 'rules'.
Suggestion: rules
...e even are blind. Furthermore, she also rule out the possibility that agnostids may ...
^^^^
Transition Words or Phrases used:
also, first, furthermore, however, if, may, second, so, therefore, well, while, in contrast
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on Part of Speech:
To be verbs : 10.0 10.4613686534 96% => OK
Auxiliary verbs: 8.0 5.04856512141 158% => OK
Conjunction : 9.0 7.30242825607 123% => OK
Relative clauses : 11.0 12.0772626932 91% => OK
Pronoun: 19.0 22.412803532 85% => OK
Preposition: 27.0 30.3222958057 89% => OK
Nominalization: 3.0 5.01324503311 60% => More nominalizations (nouns with a suffix like: tion ment ence ance) wanted.
Performance on vocabulary words:
No of characters: 1417.0 1373.03311258 103% => OK
No of words: 268.0 270.72406181 99% => OK
Chars per words: 5.28731343284 5.08290768461 104% => OK
Fourth root words length: 4.04607285448 4.04702891845 100% => OK
Word Length SD: 2.57717535561 2.5805825403 100% => OK
Unique words: 153.0 145.348785872 105% => OK
Unique words percentage: 0.570895522388 0.540411800872 106% => OK
syllable_count: 442.8 419.366225166 106% => OK
avg_syllables_per_word: 1.7 1.55342163355 109% => OK
A sentence (or a clause, phrase) starts by:
Pronoun: 3.0 3.25607064018 92% => OK
Article: 8.0 8.23620309051 97% => OK
Subordination: 4.0 1.25165562914 320% => Less adverbial clause wanted.
Conjunction: 0.0 1.51434878587 0% => OK
Preposition: 3.0 2.5761589404 116% => OK
Performance on sentences:
How many sentences: 13.0 13.0662251656 99% => OK
Sentence length: 20.0 21.2450331126 94% => OK
Sentence length SD: 65.3465952808 49.2860985944 133% => OK
Chars per sentence: 109.0 110.228320801 99% => OK
Words per sentence: 20.6153846154 21.698381199 95% => OK
Discourse Markers: 7.0 7.06452816374 99% => OK
Paragraphs: 5.0 4.09492273731 122% => 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 : 7.0 4.45695364238 157% => 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: 0.165641031514 0.272083759551 61% => OK
Sentence topic coherence: 0.0654006831743 0.0996497079465 66% => OK
Sentence topic coherence SD: 0.0496375463029 0.0662205650399 75% => OK
Paragraph topic coherence: 0.0977483724267 0.162205337803 60% => OK
Paragraph topic coherence SD: 0.0296654785055 0.0443174109184 67% => OK
Essay readability:
automated_readability_index: 13.8 13.3589403974 103% => OK
flesch_reading_ease: 42.72 53.8541721854 79% => OK
smog_index: 3.1 5.55761589404 56% => Smog_index is low.
flesch_kincaid_grade: 12.3 11.0289183223 112% => OK
coleman_liau_index: 13.4 12.2367328918 110% => OK
dale_chall_readability_score: 8.75 8.42419426049 104% => OK
difficult_words: 70.0 63.6247240618 110% => OK
linsear_write_formula: 13.5 10.7273730684 126% => OK
gunning_fog: 10.0 10.498013245 95% => OK
text_standard: 14.0 11.2008830022 125% => OK
What are above readability scores?
---------------------
Rates: 80.0 out of 100
Scores by essay e-grader: 24.0 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.