Neotropical coastal mangrove forests are usually zonal, with certain

Question

Practice Passage 
Passage No.: 12
Questions: 61 to 63
Page: 44, 45  
   Neotropical coastal mangrove forests are usually “zonal,” with certain mangrove species found predominantly in the seaward portion of the habitat and other mangrove species on the more landward portions of the coast. The earliest research on mangrove forests produced descriptions of species distribution from shore to land, without exploring the causes of the distributions.

The idea that zonation is caused by plant succession was first expressed by J. H. Davis in a study of Florida mangrove forests. According to Davis’ scheme, the shoreline is being extended in a seaward direction because of the “land-building” role of mangroves, which, by trapping sediments over time, extend the shore. As a habitat gradually becomes more inland as the shore extends, the “land-building” species are replaced. This continuous process of accretion and succession would be interrupted only by hurricanes or storm flushings.

Recently the universal application of Davis’ succession paradigm has been challenged. It appears that in areas where weak currents and weak tidal energies allow the accumulation of sediments, mangroves will follow land formation and accelerate the rate of soil accretion; succession will proceed according to Davis’ scheme. But on stable coastlines, the distribution of mangrove species results in other patterns of zonation; “land building” does not occur.

To find a principle that explains the various distribution patterns, several researchers have looked to salinity and its effects on mangroves. While mangroves can develop in fresh water, they can also thrive in salinities as high as 2.5 times that of seawater. However, those mangrove species found in freshwater habitats do well only in the absence of competition, thus suggesting that salinity tolerance is a critical factor in competitive success among mangrove species. Research suggests that mangroves will normally dominate highly saline regions, although not because they require salt. Rather, they are metabolically efficient (and hence grow well) in portions of an environment whose high salinity excludes plants adapted to lower salinities. Tides create different degrees of salinity along a coastline. The characteristic mangrove species of each zone should exhibit a higher metabolic efficiency at that salinity than will any potential invader, including other species of mangrove.   1 
 D 
1. The primary purpose of the passage is to

(A) refute the idea that the zonation exhibited in mangrove forests is caused by adaptation to salinity
(B) describe the pattern of zonation typically found in Florida mangrove forests
(C) argue that Davis’ succession paradigm cannot be successfully applied to Florida mangrove forests
(D) discuss hypotheses that attempt to explain the zonation of coastal mangrove forests
(E) establish that plants that do well in saline forest environments require salt to achieve maximum metabolic efficiency
 
 2 
 B 
2. According to the passage, the earliest research on mangrove forests produced which of the following?

(A) Data that implied random patterns of mangrove species distribution
(B) Descriptions of species distributions suggesting zonation
(C) Descriptions of the development of mangrove forests over time
(D) Reclassification of species formerly thought to be identical
(E) Data that confirmed the “land-building” role of mangroves
 
 3 
 E 
3. It can be inferred from the passage that Davis’ paradigm does NOT apply to which of the following?

(A) The shoreline of Florida mangrove forests first studied by Davis
(B) A shoreline in an area with weak currents
(C) A shoreline in an area with weak tidal energy
(D) A shoreline extended by “land-building” species of mangroves
(E) A shoreline in which few sediments can accumulate

4 
 C 
4. Information in the passage indicates that the author would most probably regard which of the following statements as INCORRECT?

(A) Coastal mangrove forests are usually zonal.
(B) Hurricanes interrupt the process of accretion and succession that extends existing shorelines.
(C) Species of plants that thrive in a saline habitat require salt to flourish.
(D) Plants with the highest metabolic efficiency in a given habitat tend to exclude other plants from that habitat.
(E) Shorelines in areas with weak currents and tides are more likely to be extended through the process of accumulation of sediment than are shorelines with strong currents and tides.

atl12688 · Accepted Answer

Here is my attempt at an explanation of my choices (these are not official nor have I seen OE):
Answers: 1) D 2) B 3) E
Q1 :- The primary purpose of the passage is to

(A) refute the idea that the zonation exhibited in mangrove forests is caused by adaptation to salinity --   Salinity principle is discussed in Para-4 and the author does not refute this principle  
(B) describe the pattern of zonation typically found in Florida mangrove forests --   Florida is merely the location where J.H. Davis conducted his research   
(C) argue that Davis’ succession paradigm cannot be successfully applied to Florida mangrove forests --   Author does not argue Davis' paradigm can't work in Florida. The author brings up other researchers challenging the paradigm in non-weak current/tidal energy locations  
(D) discuss hypotheses that attempt to explain the zonation of coastal mangrove forests --   General statement encompassing the entire passage and the discussion that takes place  
(E) establish that plants that do well in saline forest environments require salt to achieve maximum metabolic efficiency --   Only partial scope as this is mention in the fourth paragraph only

Q2 :- According to the passage, the earliest research on mangrove forests produced which of the following?

(A) Data that implied random patterns of mangrove species distribution --   No random pattern mentioned  
(B) Descriptions of species distributions suggesting zonation --   "The earliest research on mangrove forests produced descriptions of species distribution from shore to land, without exploring the causes of the distributions"    
(C) Descriptions of the development of mangrove forests over time --   Described distribution, not development  
(D) Reclassification of species formerly thought to be identical --   Out of Scope  
(E) Data that confirmed the “land-building” role of mangroves --   No data given

Q3 :- It can be inferred from the passage that Davis’ paradigm does NOT apply to which of the following?

(A) The shoreline of Florida mangrove forests first studied by Davis --   Davis' paradigm does apply to the shoreline of Florida  
(B) A shoreline in an area with weak currents --   Davis' paradigm does apply to areas with weak currents  
(C) A shoreline in an area with weak tidal energy --   Davis' paradigm does apply to areas with weak tidal energy  
(D) A shoreline extended by “land-building” species of mangroves --   if the paradigm occurs then "land-building" takes place  
(E) A shoreline in which few sediments can accumulate --   Combining "But on stable coastlines, the distribution of mangrove species results in other patterns of zonation; “land building” does not occur." and "“land-building” role of mangroves, which, by trapping sediments over time, extend the shore" we can infer that with few accumulated sediments, the paradigm will not work (this is precisely why the paradigm was challenged by other researchers)

AndrewN · Answer

I would be happy to give it a go,  shabuzen102 . I did choose (C) because I could not find a way to disprove it, based on the same line from the passage that  TarunTilokani  quoted above. If you look carefully at the last line of the passage, though, the other part that mentions  metabolic efficiency , you can see how, combined with the line you quoted above, it really does not justify choice (D). Again, that line:

The characteristic mangrove species of each zone should exhibit a higher metabolic efficiency at that salinity than will any potential invader, including other species of mangrove.

Notice that the passage is comparing the metabolic efficiency of the  mangrove species of each zone  with that of  any potential invader , specifically at whatever  salinity  that zone exhibits. Thus, the well-adapted mangrove keeps other  invaders  at bay, but that is all we can tell. Now look at choice (D) again, in the context of the question:

Q :  Information in the passage indicates that the author would most probably regard which of the following statements as INCORRECT?

(D) Plants with the highest metabolic efficiency in a given habitat tend to include other plants from that habitat.

Do we know that, to quote the passage,  the characteristic mangrove species of each zone  will NOT, to borrow from the answer,  include other plants from that habitat ? Not at all. Whether "dominant" mangroves, as I will call them, tolerate other well-adapted,  high-salinity  plants in a zone with high salinity is beyond the scope of the passage. Again, all we can ascertain is that such mangroves are adapted well to that environment metabolically and prevent other invasive species from playing the dominant role. Other plants could or could not be present, but the author does not take a stance either way.

I hope that helps. If you have further questions, let me know. Good luck with your studies.

- Andrew

warrior1991 · Answer

4. Information in the passage indicates that the author would most probably regard which of the following statements as INCORRECT?

(A) Coastal mangrove forests are usually zonal.
(B) Hurricanes interrupt the process of accretion and succession that extends existing shorelines.
(C) Species of plants that thrive in a saline habitat require salt to flourish.
(D) Plants with the highest metabolic efficiency in a given habitat tend to include other plants from that habitat.
(E) Shorelines in areas with weak currents and tides are more likely to be extended through the process of accumulation of sediment than are shorelines with strong currents and tides.

workout   adkikani   JarvisR   abhimahna   Skywalker18 
Guys I know C is correct as it is clearly mentioned in the passage but what about D??

How come D is correct? 
Please help!!

Nikhil · Answer

I don't think we can evaluate the correctness of option D based on the passage. We can certainly do for option C.

Now option D which states "Plants with the highest metabolic efficiency in a given habitat tend to include other plants from that habitat".

This statement may be true that plants with the highest metabolic efficiency in a given habitat tend to include other plants from that habitat but the salinity of the water might be hurting the growth of the other plants

or

The plants with the highest metabolic efficiency themselves do not allow the growth of other plants.

I see two possible cases and hence I went with option C

aragonn · Answer

P1- M; diff species; a study on distribution.
P2- t1 jhd - on distribution
P3- t1 challenged, t2
P4- defining mangrove properties related to saline.

Main Point - Different species for defining mangrove distribution.

1. The primary purpose of the passage is to

(A) refute the idea that the zonation exhibited in mangrove forests is caused by adaptation to salinity - no
(B) describe the pattern of zonation typically found in Florida mangrove forests - no
(C) argue that Davis’ succession paradigm cannot be successfully applied to Florida mangrove forests - no
(D) discuss hypotheses that attempt to explain the zonation of coastal mangrove forests - This one seems like the best choice. covering all para graphs.
(E) establish that plants that do well in saline forest environments require salt to achieve maximum metabolic efficiency - no

----------------------------------------------------

2. According to the passage, the earliest research on mangrove forests produced which of the following?
anchor - the earliest research on mangrove forests
given in p1 - The earliest research on mangrove forests produced descriptions of species distribution from shore to land, without exploring the causes of the distributions.

(B) Descriptions of species distributions suggesting zonation
----------------------------------------------------
4. Information in the passage indicates that the author would most probably regard which of the following statements as INCORRECT?

(C) Species of plants that thrive in a saline habitat require salt to flourish. - Research suggests that mangroves will normally dominate highly saline regions, although not because they require salt.

-----------------------------------------------------

workout  - can you give me a hand for q3. I selected option D over E. here is my reason.
(D) A shoreline extended by “land-building” species of mangroves ---But on stable coastlines, the distribution of mangrove species results in other patterns of zonation; “land building” does not occur. --- if “land building” does not occur. then we can not apply Davis’ paradigm. Also this line suggest it does. "According to Davis’ scheme, the shoreline is being extended in a seaward direction because of the “land-building” role of mangroves,"
(E) A shoreline in which few sediments can accumulate - According to Davis’ scheme, the shoreline is being extended in a seaward direction because of the “land-building” role of mangroves, which, by trapping sediments over time, extend the shore.

Salsanousi · Answer

aragonn

For q3

Refer to this line "Recently the universal application of Davis’ succession paradigm has been challenged.  It appears that in areas where weak currents and weak tidal energies allow the accumulation of sediments , mangroves will follow land formation and accelerate the rate of soil accretion; succession will proceed according to Davis’ scheme"

We are asked about the cases in which Davis' Paradigm does not apply.

If it applies to an area that allows the accumulation of sediments (there must be enough sediments to accumulate). It would be safe to infer that it would not happen if there were fewer sediments.

I hope this helps.

TarunTilokani · Answer

4. Information in the passage indicates that the author would most probably regard which of the following statements as INCORRECT?

(A) Coastal mangrove forests are usually zonal.

(B) Hurricanes interrupt the process of accretion and succession that extends existing shorelines.

(C) Species of plants that thrive in a saline habitat require salt to flourish.

(D) Plants with the highest metabolic efficiency in a given habitat tend to include other plants from that habitat.

(E) Shorelines in areas with weak currents and tides are more likely to be extended through the process of accumulation of sediment than are shorelines with strong currents and tides.

Answer C
portion from the passage : Research suggests that mangroves will normally dominate highly saline regions,  although not because they require salt .

shabuzen102 · Answer

Would someone please explain why Option D in Question 4 is incorrect? 
Here's the relevant information in the passage:
"Rather, they are metabolically efficient (and hence grow well) in portions of an environment whose high salinity excludes plants adapted to lower salinities"

Thank you!

gmatway · Answer

While I don't have any doubt on your approach . I have one small problem . Can anyone confirm that in such EXCEPT questions may be the passage supports the line can the options stay NEUTRAL? Is this possible that we need to got for options which passage supports clear truth or lie no grey areas like in CR ?

AndrewN · Answer

Hello,  gmatway . I am having a little trouble grasping what you intend to say, but I think you mean to ask whether there  must be  direct textual evidence to support or refute an answer choice in RC questions, as opposed to preserving a little mystery, a so-called grey area, similar to what you may find in some CR questions. To be sure, I do think RC and CR questions often rely on the same skillset to break down what the questions are asking and how to use the information presented in the passage to weigh the pros and cons of each answer choice. It seems to me as if RC questions lean a little more on direct textual evidence, but there are, on occasion, inference questions that may require the reader to piece together different parts of the text in such a way that someone could say the answer to that question fell in a sort of grey area. Do you have any particular questions in mind from either CR or RC to illustrate what you may mean, re these EXCEPT questions? I might understand your point a little better by way of such an illustration.

- Andrew

Cellchat · Answer

Seem to be a lone wolf on this one but I had trouble on Q2.

Q2 :- According to the passage, the earliest research on mangrove forests produced which of the following?

(A) Data that implied random patterns of mangrove species distribution
(B) Descriptions of species distributions suggesting zonation

A and B were my favourites, and each relies on the quote --  "The earliest research on mangrove forests produced descriptions of species distribution from shore to land, without exploring the causes of the distributions" . I just thought B went a little too far by mentioning 'zonation', as you have to be super careful with trap answer choices etc.
I chose A because without knowing the causes of the distribution, to the researchers the pattern must have looked random. Tbh, A seems flawed now I think about it but so does B.

Can someone help me with why we can suggest zonation in B?

Thelionking1234 · Answer

How can we eliminate option E from question 4?

Because no comparison is given in passage between weak and strong currents. Only about weak is mentioned.

GMATNinja  @e-gmat Please help

GMATNinja · Answer

Let's take a look at the passage before examining (E) to see why it is not the correct answer.

I think you're referring to this part of the passage:
 
You're right that strong currents are not mentioned here. However, we are told that  "weak currents and weak tidal energies"   allow  the sediment to accumulate. The author CONTRASTS these areas to  "stable coastlines,"  where  ""land building” does not occur."

While we're not told anything about areas with strong currents or strong tidal energies, the suggestion is that strong currents and strong tidal energies  would not allow  the accumulation of sediment.

(E) tells us:
 
While the author never EXPLICITLY states that strong currents and tides would prevent the accumulation of sediment, the part of the passage quoted above suggests  "the author would most probably regard"  (E) as CORRECT.

This means (E) cannot be the correct answer to this question.

Compare this to what is written in (C):
 
There are two parts of the passage we can use to show that (C) is the correct answer. The first is given early in the final paragraph:

While mangroves can develop in fresh water, they can also thrive in salinities as high as 2.5 times that of seawater.

This paragraph goes on to say:

Research suggests that mangroves will normally dominate highly saline regions, although not because they require salt.

Mangroves are the only saltwater plant mentioned in this passage so we can use them to answer this question. We can see from these parts of the passage that a plant that  thrives in a saline habitat  does not  require salt .

This is sufficient evidence for us to say the author would see the information in (C) as INCORRECT -- (C) is our answer to this question.

I hope that helps!

nikitamaheshwari · Answer

Can someone please explain option D of Q4 - Plants with the highest metabolic efficiency in a given habitat tend to include other plants from that habitat.

The last line mentions that Mangrove species exhibit a higher metabolic efficiency at that salinity than will any potential invader, including other species of mangrove and also they survive best with no competition. So, why will they include other plants ? should n't this be incorrect too?

GMATNinja   karishma

Thanks
Nikita

bM22 · Answer

Hi nikitamaheshwari , Please refer this answer: https://gmatclub.com/forum/neotropical- ... l#p2457044 Let me know if you still have doubts. Thanks.

shirishgupta77 · Answer

All 4 correct, Time : 10min.
Can anyone please suggest me how do i increase my speed in RC(or in Verbal section in general).
Current approach : I read the whole passage in about 2 min. and then answer each question and mostly i can mark the correct answer, but it does me about 2 min., to attempt each question.

jcerdae · Answer

Thanks god you also had the same problem!
I also was between A & B, being B less correct because of the "Zonation" word which is mentioned in the 2nd paragraph, which I interpret as a term which didnt come from the earliest research on mangover forests.

Sneha2021 · Answer

jcerdae

Summary of first para: 
Neotropical coastal mangrove forests are usually “zonal,” with certain mangrove species found predominantly in the seaward portion of the habitat and other mangrove species on the more landward portions of the coast
The earliest research on mangrove forests produced descriptions of species distribution from shore to land, without exploring the causes of the distributions.

1) Definition of "Zonal" is defined as distribution from shore to land.
2) Research has produced descriptions of species distribution basis shore to land.

A is incorrect because we don't have information whether distribution is uniform or random. This is out of scope. Combining 1 and 2, we can clearly say that distributions suggesting zonation (refer to 1)

jcerdae · Answer

Thank you very much for your explanation!!!

Neotropical coastal mangrove forests are usually zonal, with certain

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Neotropical coastal mangrove forests are usually zonal, with certain

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