Q23

[danielalfino]

Hello ATLAS,

I had a lot of trouble with this whole passage. I ran out of time which is why I got a few wrong, but I'm still not able to fully understand the questions and answers.

On 23, I had originally crossed out each answer choice, and I simply was forced to guess at the end. I understand in the untreated plots, nothing would change, and thus, that cyclamen would be controlled. But beyond that, answer choice A seemed just as much as a stretch as answer choice D. Nothing in the passage concerned additional environmental changes except for the mention of seasonal change. If this is the part of the passage from which we are supposed to draw the answer, I am unable to make sense of A as the correct answer because this change is cyclical and thus, populations ought to revert to the same levels in the Winter, Spring, etc. Thus, I crossed both answers out. B and E are wrong because the answers are relative, and thus I chose C, though I had originally crossed it out. I just didn't like any of these answers, and I thought the scenario asked us to assume way too much if A is the correct answer.

Thanks.

[giladedelman]

Thank you for the questions. This is an extremely challenging passage, indeed!

Let's look at Q23 first. What could we expect to happen if the experiments used a pesticide that slows the reproduction of cyclamen mites and has no other effects? Well, we already know that Typhlodromus (hereafter to be referred to as Big T) effectively controls cyclamen mites, and that one of the reasons for its effectiveness it that it is highly responsive to changes in the mites' population. So, if Big T ordinarily controls the mites, and now we're adding a pesticide that slows the mites' reproduction down, we can bet that the mites will still be under control!

(A) is correct. This is what we just said: we know that the mites will be under control in the untreated plots, and since the only difference in the treated plots is that the mites reproduce more slowly, they should be under control there, too.

(B) is a disaster. First, it's out of scope: the experiments don't involve plots from which Big T is absent. Second, it's a contradictory interpretation: if Big T were absent, we would expect more mites, not fewer.

(C) is an unsupported interpretation. We don't know how slower rates of mite reproduction would affect the seasonal synchrony between the two species.

(D) is an unsupported interpretation. I found it tempting, because we might expect Big T populations to decrease as the mites' reproduction rate slows; but we have no way to know whether they'll eventually increase.

(E) is another unsupported interpretation. We have no basis to judge either of these two claims.

Okay, does that make Q23 any clearer?

[opulence2001]

Hello.
I'm still a bit confused as to why A is the correct answer to Q23. I think what's throwing me off is the way the answer is phrased. It says: in plots inhabited by both T and C the latter would have been effectively controlled.

This is what's throwing me off since I thought that either way the C population would be under control. C and T with no pesticide will be under control, and C and T with pesticide will slow down reproduction of C, but T will adjust thus resulting in no change, and the C still being in check. But A says the latter would.

I eliminated A because it compares the two plots and says only the latter would be effective. Please advise! My brain hurts...

[giladedelman]

Careful. Answer (A) says:

In both treated and untreated plots inhabited by both Typhlodromus and cyclamen mites, the latter would have been effectively controlled.

"The latter" refers to cyclamen mites, not to untreated plots. (It wouldn't make any sense to say that a plot was controlled.) So this is saying that in both settings, the population of C would be controlled, which is exactly how you correctly described what we should expect.

(P.S. this answer never says "only" the latter is controlled, so even if it were comparing the two plots in the way you thought, it wouldn't be wrong. Saying that the population is controlled in the latter doesn't mean it isn't controlled in the former.)

[opulence2001]

"I see! I see!" said the blind man...

I get it now...thanks so much! The tip about not assuming "only" is of great help especially for other questions.

[ymcho2013]

but wouldn't answer choice C have some validity because in the passage, lines 23-25 seem to indicate that they do have reproductive synchrony. And so if you added a pesticide that slowed down the mites' reproductive rate, wouldn't that break its synchrony with the predators?

[niohelang]

but wouldn't answer choice C have some validity because in the passage, lines 23-25 seem to indicate that they do have reproductive synchrony. And so if you added a pesticide that slowed down the mites' reproductive rate, wouldn't that break its synchrony with the predators?

Yeah I have the same problem, can someone explain that? THX

[jasonshaffer0]

but wouldn't answer choice C have some validity because in the passage, lines 23-25 seem to indicate that they do have reproductive synchrony. And so if you added a pesticide that slowed down the mites' reproductive rate, wouldn't that break its synchrony with the predators?

Yeah I have the same problem, can someone explain that? THX

I believe "reproductive synchrony" is described in lines 32 and 33: "They do not reproduce except when feeding on cyclamen mites." Therefore the rate at which the C mites reproduce is irrelevant. Synchrony is achieved, just at a slower rate. As the C mite reproduction decreases, there is less food for the T mites, which slows the reproduction rates of the T mites as well, and we still have synchrony.

[T.J.]

I was in the same shoes with many of you as I also chose C. After going back to the passage, I found out that only SEASONAL synchrony is mentioned (Line 23); then the passage goes on how the T-bug would survive under the harsh winter. It's about their seasonal adaptation. I am dubious on whether there is a reproductive synchrony. First, the passage does not mention it. Second, even if there is one, it is introduced under the umbrella of the seasonal synchrony. This is my rationale for not choosing C, as it is largely unsupported and drawing invalid inferences. Hope you guys find this helpful.

[christine.defenbaugh]

Absolutely beautiful discussion here guys! T.J. and jasonshaffer0 are rocking out on this!

The critical 'synchrony' described in the passage is the "seasonal synchrony" in lines 23-24. This synchrony matches up the reproduction of the Typhlodromus with the population size of the cyclamen mite. So, you're both spot on that slowing down the cyclamen reproduction would not break this synchrony. (Presumably, as jasonshaffer0 notes, the cyclamen population would drop, which would then reduce the Typhlodromus reproduction, and the original synchrony is easily maintained.)

I do think T.J. has the right of it that there is no reproductive synchrony, though. Technically, reproductive synchrony would mean that that two populations are spawning at nearly the same time. There's no evidence in the passage that this relationship exists between the two mites' reproductive cycles. It is entirely possible, for instance, that when the cyclamen mite population is very low, and thus Typhlodromus has stopped reproducing, that the small population of cyclamen is still reproducing. If that were true, there could not be a general case of reproductive synchrony between the two species.

Awesome work, you two. Keep it up!

[seychelles1718]

Could someone provide some advice on how to approach this question?
So when I solved this question during PT, I realized the question stem refers to the experiments in the passage (3rd Paragraph). So I quickly re-read the paragraph because the question asks us what would occur in the experiments mentioned in the passage.
But turns out understanding the experiments were not that helpful to pick the right answer. In my opinion, the question is asking us to reinforce the main point/ central idea of the passage: the predator T is effective at controlling its prey, cyc, which is what A says.

So I wonder how the LSAT Geeks approached this question?

Thanks!

[ManhattanPrepLSAT1]

The right answer can still be reached from the information in the 3rd paragraph, but you do need to understand the importance of the last sentence in the 3rd paragraph. Generally, when a question directs you to a specific part of the passage, it's best to work within the information presented in that part. Patrick Tyrrell (another forum warrior) calls this the proof window, which I find to be a very helpful way of thinking about where to go looking in the passage for information to a question like this.

The study involves comparing two plots: one using an insecticide (parathion) to eliminate the predator Typhlodromus, which should have the impact of allowing cyclamen mite populations to grow unchecked and the other using Typhlodromus to control cyclamen mite populations. If pesticide X would control cyclamen mite populations and that were to replace the pesticide that allowed cyclamen mite populations to grow unchecked, then cyclamen mite populations would be controlled in that plot as well--best expressed in answer choice (A).

Sure, this reasoning does involve understanding that the experiment was intended to support the main idea of the passage and so we should keep the main idea in mind, I don't think we need to look outside of Paragraph 3 to answer this question.

INCORRECT ANSWERS
(B) contradicts the passage. Typhlodromus control cyclamen mite populations.
(C) is unsupported. This speculates on what would happen to the reproductive synchrony between Typhlodromus and cyclamen mite populations.
(D) is unsupported. While Typhlodromus populations might decrease as the cyclamen mite population decreases, it is not supported that the Typhlodromus population would eventually increase.
(E) is unsupported. The passage does not provide information to support the claim that cyclamen mite populations in the treated plots would reach damaging levels.

[renata.gomez]

Hi!

I don't know if anyone made the same flaw in reasoning as I did, but I got it down to A and E and chose E because I thought A couldn't be possible since there wasn't a treated plot with both the prey and predator in the experiment detailed in the third paragraph. The only treated plot was predator free; however, by substituting it with a pesticide that has no effect on the predator, then the scenario of a treated plot with both predator and prey becomes viable.

I guess this demonstrates the importance of remember and applying the question stem