Q15 - Seemingly inconsequential changes in sea

[ManhattanPrepLSAT1]

The conclusion of the argument is that "seemingly inconsequential changes in sea temperature due to global warming eventually result in declines in fish and seabird populations."

The evidence for this is that a rise in temperature restricts the upwelling that brings phytoplankton to zooplankton. and that zooplankton is the source of food for the rest of the food chain.

We are asked to describe the role of the claim that zooplankton feed upon phytoplankton. This is evidence in support of the conclusion of the argument.

(A) misrepresents the role of the claim. The claim is evidence, whereas, this answer choice suggests that it serves as a conclusion - either intermediary or primary. But the claim from the question stem is not supported by any other claim in the argument.
(B) is not quite accurate. It is not an example of how vertical mixing of seawater affects feeding habits. For this answer choice to be correct, the claim from the question stem would need to be about a change in behavior of feeding habits based on differences in the vertical mixing of seawater.
(C) is correct. The claim does help support the conclusion of the argument, and the conclusion of the argument is that changes in sea temperature can affect larger sea animals.
(D) is way off track. This would require the additional assumption that the author actually wants us to take measures against global warming. This feeds off of our everyday common sense. Sure we want to curtail global warming, but that is not ever mentioned in the argument.
(E) is close but stretches it a bit too far when it says that "global warming poses a threat to all animals." We know this is true because zooplankton feed the rest of the food chain. But the conclusion of the argument is strictly about fish and seabird populations.

[geverett]

Hey Matt,
Do you think answer choice B more accurately describes sentence 3 in this stimulus? I picked answer choice C, but I am trying to definitely disprove answer choices in my quest to go deeper with the content.

[ManhattanPrepLSAT1]

That will pay huge dividends as you go. So definitely go the extra mile on each question. You can study only a third of the questions that someone else studies and learn more, if you really dig into what makes a great "wrong" answer choice.

Great "wrong" answer choices are ones that play off an easily followed misunderstanding of the argument. There are frequently several common misreads of an argument that lead students to very specific wrong answer choices. Try and categorize incorrect answers as well, as being wrong for specific but generic reasons - detail creep, issue of degree, reversed logic, etc.

The more you see that the wrong answers are wrong for consistently the same reasons, the easier time you will have in making some of those final eliminations you'll need to make under tons of pressure.

To your point though, answer choice (B) does represent the the role of the third sentence very well, so yes! Good work!

[vik]

Ans B should say...."part of an example of the way in which the prevention of mixing of sea water..."

[eapetrilli]

(B) is also incorrect because the point about vertical mixing in the second sentence is an unsupported premise. If we break the argument down as (B) would have us then we get: conclusion-support-example of that support. However, the second sentence is not the extent of the author's intended support. The conclusion derives from how the following sentences complement one another and none of the sentences can stand apart.

[acechaowang]

The way how i ruled out B is that first of all, this argument does not talk anything about change of feeding habits. It just talked about zoopankton will die due to the rise in temperature. Second, the subject in the second sentence is the rise fo just two degrees, so it is talking about how the rise of two degrees will affect the food chain, nothing about the vertical mixing of the seawater.

[beonica]

This may seem like a silly question but I there is no mention of larger sea animals.
This completely threw me off. I thought we were not suppose to select word changes

[Shea.y.schneider]

Without knowing what zooplanktons and phytoplanktons are one can assume that if zooplanktons feed upon phytoplanktons their larger of the two. However, I was still thrown off by the answer choice C mentionn of larger sea animals. On the other, through the process of elimination and logical assumptions, answer choice c makes the best fit.

[samjcg]

Without knowing what zooplanktons and phytoplanktons are one can assume that if zooplanktons feed upon phytoplanktons their larger of the two. However, I was still thrown off by the answer choice C mentionn of larger sea animals. On the other, through the process of elimination and logical assumptions, answer choice c makes the best fit.

This may seem like a silly question but I there is no mention of larger sea animals.
This completely threw me off. I thought we were not suppose to select word changes

Larger sea animals in this context are referring to sea animals that are larger than zooplankton.

[Mab6q]

Honestly, I was thrown off by the large animals in C. I think it's a bad answer, but I'll give it the sight nod over B.

[ohthatpatrick]

This is definitely a question in which the correct answer is easier with the outside knowledge that "fish and seabirds" are larger than plankton.

Despite the fact that on many questions, LSAT forces us to spell out common sense, that doesn't mean there's no such thing as outside knowledge on LSAT.

After all, we need to know the definitions of the words used. There will be questions on RC that ask about the author's tone, and if you don't know the meaning of 'tacit' or 'vituperative', then the question will be harder (but still possible through process of elimination).

As others have indicated, if we're not aware that plankton are incredibly small organisms, we might still infer the size continuum from our common sense notions of "higher on the food chain generally means bigger".

Part of what helps me like (C) is knowing that most Describe the Function questions involve affirming the overall conclusion of the argument.

The conclusion of this argument is the first sentence. Everything that follows is support/explanation for that. So when they ask me about the claim that "zooplankton feed on phytoplankton", I want something that sounds like "it helps provide support for the first sentence".

"Global temp changes affect larger sea animals indirectly" is the closest any of these answer choices get to saying "small changes in sea temp eventually result in declines in fish and seabird population".

(B) got a lot of love/confusion in this thread, but I would encourage us to spell out whether it makes any sense.

Here's how (B) describes the argument:
The vertical mixing of seawater affects feeding habits.
For example, zooplankton feed up phytoplankton.

Huh?

=== other answers ===
(A) Z's feeding on P's is a fact, not a hypothesis. Also it is providing support, not being supported.

(D) "global warming MUST BE curtailed" is not a thought we were given in this argument. This is the trap of "going beyond the argument / assuming what this author might ALSO believe/say"

(E) "global warming poses a threat to ALL organisms" is also not a thought we were given in this argument. Granted, this is closer to what we heard than (D), and you might INFER that global warming threatens all organisms from the idea that Z's feed the rest of the food chain, and Z's are negatively impacted by global warming. But, the conclusion is strictly about declines in fish and seabird populations, so (C) is a much tighter fit.

Hope this helps.