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There are a great many symbiotic relationships in the marine

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There are a great many symbiotic relationships in the marine  [#permalink]

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New post 04 Sep 2018, 17:39
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There are a great many symbiotic relationships in the marine environment. A popular one, often noted for the striking beauty of the juxtaposition, is that of the sea anemone and the clown fish. The
anemone has poison tentacles which—when they contact passing fish— paralyze the fish and drag the prey in for a meal. The clown fish uses the anemone‘s tentacle "garden" as a safe haven while attracting prey for the anemone to capture, for it alone is immune to the sting of the anemone.

Another symbiotic relation that remains the subject of scientific puzzlement concerns the relationship between Scleractinia, the coral type 10 whose colonization produces reefs, and their symbiotic partners the zooxanthellae, the unicellular algae present in the corals‘ endodermic tissues. It is known that each symbiont plays an integral part in the formation of a reef‘s protective limestone foundation. The coral polyps secrete calceous exoskeletons which cement themselves into an 15 underlayer of rock, while the algae deposit still more calcium carbonate,which reacts with sea salt to create an even tougher limestone layer.

It is also known that, due to the algal photosynthesis, the reefenvironment is highly oxygen-saturated, while the similarly high amounts of carbon dioxide are carried off rapidly. All this accounts for the amazing 20 renewability of coral reefs despite the endless erosion caused by wave
activity. However, the precise manner in which one symbiont stimulates the secretion of calcium carbonate by the other remains unclear.

Scientists have also proposed various theories to explain thetransformation of "fringing reefs," those connected above sea level to land masses, into "barrier reefs" that are separated from shorelines by wide lagoons, and then into free-floating atolls. Though the theory postulated by Charles Darwin is considered at least partially correct, some scientists today argue that the creation of the reef forms has more to do with the rise of sea level that accompanied the end of the Ice Age. However, recent drillings at Enewetak atoll have uncovered a large underlay of volcanic rock, which suggests that Darwin‘s explanation may have been more valid after all.

Even the name given to the reefs is something of a misnomer. The Scleractinia themselves generally comprise no more than 10 percent of the biota of the average reef community: zooxanthellae can account for up to 90 percent of the reef mass, along with foraminifera, annelid worms, and assorted mollusks. Moreover, reefs can flourish only in shallow, highly saline waters above 70°F., because the algae require such circumstances; yet non-reef-building corals occur worldwide under various environmental conditions, from the Arctic to the Mediterranean, home of the red coral prized for jewellery. The most likely reason that the term "coral reefs" persists is that the brilliant variety of coral shapes and colours makes aesthetic considerations more vivid than biological ones.

1. According to the author, some scientists consider the term "coral reef" a misnomer because:

A. the beautiful shapes and colours of reefs are produced by the Scleractinia rather than the zooxanthellae.

B. the coral portion of a reef has little to do with the reef‘s survival.

C. "non-reef-building" corals are found throughout the world.

D. the majority of a reef‘s substance comprises zooxanthellae, foraminifera, annelid worms, and assorted molluscs while a small portion comprises the Scleractinia.

E. the reef does not have any coral whatsoever


2. Based on the passage, which of the following is probably an assumption of scientists studying coral reefs?

A. The theories of reef evolution through glacial melting and through volcanic subsidence are mutually exclusive.

B. The three main types of coral reefs did not develop independently of one another.

C. Zooxanthellae are always found in coral reefs.

D. Intense calcification single-handedly protects reefs from destruction by waves and other natural causes.

E. Coral reefs are always blue in colour


3. The passage mentions the recent drillings at the Enewetak atoll. This reference serves to:

A. stengthen the claims made by scientists today concerning reef transformation.

B. weaken the claims made by scientists today concerning reef transformation.

C. strengthen the claims made by Darwin concerning reef transformation.

D. weaken the claims made by Darwin concerning reef transformation.

E. has no impact on the claims made by Darwin concerning reef transformation.


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Re: There are a great many symbiotic relationships in the marine  [#permalink]

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New post 12 Sep 2018, 05:27
OEs..
1) Your map will remind you that a full paragraph discusses the misnomer ―coral reef.‖ Summarize the main reason why this is true: Reefs have lots of algae, not much coral. (D) matches the prediction.

(A): Faulty Use of Detail. The author argues at the end of ¶5 that this is why the term persists, but it doesn‘t explain the misnomer. (B): Distortion. While the reef‘s conditions for growth depend on the algae, the coral could also play a major role in determining survival.

(C): Faulty Use of Detail. While true as described in ¶5, this doesn‘t explain why the term ―coral reef‖ would be misleading.

(D): The correct answer

(E): Extreme language. The reef does have coral.

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Re: There are a great many symbiotic relationships in the marine  [#permalink]

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New post 12 Sep 2018, 05:28
2) A difficult question to predict; review the main points of the passage in your map. Remember to eliminate while looking for the correct answer, using the denial test as needed. (B) must be an assumption of the scientists since they study the different types of reefs with the intent of understanding how they transformed from to another. Denying (B) and arguing that the three types developed independently destroys the transformation theories that the author discusses.

(A): Opposite. The author argues in ¶4 that Darwin‘s theory may be ―partially true,‖ suggesting that the two theories can coexist to some extent.

(B): The correct answer

(C): Opposite. The author mentions corals without algae in the last part of ¶5.

(D): Opposite. The author shows in ¶s2 and 3 that a variety of factors influence reef renewal.

(E):This could be a conclusion but doesn‘t have to be an assumption


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There are a great many symbiotic relationships in the marine  [#permalink]

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New post 12 Sep 2018, 05:29
3) How does the Enewetak atoll fit into the passage? Mentioned in ¶4, the author argues that it supports Darwin‘s theories about barrier reef formation. (C) matches the prediction exactly.

(A): Out of Scope. While it strengthens the claims of some scientists, it can‘t strengthen the claims scientists in general since there are competing theories.

(B): Out of Scope. As above.

(C): The correct answer

(D): Opposite. The author states explicitly that the evidence strengthens Darwin‘s theory.

(E): Incorrect, as described above

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There are a great many symbiotic relationships in the marine &nbs [#permalink] 12 Sep 2018, 05:29
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There are a great many symbiotic relationships in the marine

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