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#21 - Essayist: When the first prehistoric migrations of

reop6780
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I really had no idea how answer C weakened the stimuli.

The stimuli states that only because the migrants carried certain microorganism, it is the primary cause for the extinctions of animals 2000 years later.

I looked for an answer that suggests a different cause for the extinctions other than the microorganism.

There was none that I was expecting.

I really do not know what C does. Does it matter to know "very few species" were extinct instead of "many species" for example?

:-?
Adam Tyson
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Remember the five classic ways to weaken a causal argument - 1) alternate cause, 2) cause without effect, 3) effect without cause, 4) the alleged cause and effect may be reversed, and 5) data attack (some problem with the underlying data, study, experiment, whatever that led to the causal conclusion).

Our author argues that it was probably the microorganisms, not hunting, that caused the extinctions. Answer choice C gives us an example of "cause without effect" - we are told that some animals, who would have presumably been exposed to the same microorganisms, did not become extinct. It's actually better than that, though, because answer C also strengthens the alternate cause, hunting, by showing that where that cause was absent (animals that were not hunted) the effect (extinction) was also absent. By strengthening the alternate cause we also weaken the proposed cause. It's a two-fer answer!

Hope that helps. Best of luck!
Adam M. Tyson
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MBG13
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I went back to analyze this one and I select C the second time around and I understand why its correct.

I initially chose A because I was frustrated with choice E and I didn't see what I was expected (i.e., a third cause for the phenomenon and I completely forgot that if there is no cause, then there is no effect.) and decided to just pick an answer and move on.

I became really frustrated with E because I trying to figuring out what the heck choice E was getting at and I burned a lot of time. I was perplexed because E seemed to repeat the premise in the stimulus and I thought it was a trick answer. I know I'm over thinking this incorrect answer...but I gotta know so I can stop thinking about this silly question and move on ... what's up with E.
Nikki Siclunov
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Hi MBG13,

Thanks for your question!

Answer choice (E) simply states that some other species in North America became extinct after the aforementioned 2,000 year period. This is entirely irrelevant to the argument, which is only concerned with the cause for the extinction of species that became extinct in the first 2,000 years after humans migrated from Asia to North America. The fact that other species became extinct later than that has no bearing on the conclusion of the argument.

Hope this helps! :)

Thanks,
Nikki Siclunov
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nutcracker
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Hello,

It took me a long time to realize that I completely misinterpreted the wording in answer choice (C). I understood it as saying that except the "very few species" that were extinct 2000 years after the first migrations, all the other species had become extinct within 2000 years, instead of staying extant beyond 2000 years!

However, now that I see what (C) is really saying, I can't seem to find a qualitative difference between (C) and (E). Both are essentially saying that some species managed to survive more than 2000 years after the first migrations. Is (C) better because it mentions the hunting aspect? Thank you very much!
Eric Ockert
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Hey nutcracker!

I wouldn't say that (C) is better than (E) so much as (E) just doesn't really have any effect on the argument.

If you really think about answer (E), it is almost certainly true in the real world. But so what? Without any other information than that, this does not point towards or away from any particular cause.

In the stimulus, you are given the fact that the new arrivals "encountered" these soon-to-be extinct animals. The author seems to rule out hunting as the cause, and points to microorganisms brought by the migrants as the cause of these extinctions. (C) really points back to hunting as the cause. This weakens the author's explanation.

(E) on the other hand doesn't really point to anything. Did these animals encounter the migrants? Were they hunted? We would need to know a bit more information about these extinct animals for (E) to have an impact on this argument.

Hope that helps!
Eric Ockert
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nutcracker
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That's helpful. Thanks Eric!
LSAT2018
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Adam Tyson wrote:Our author argues that it was probably the microorganisms, not hunting, that caused the extinctions. Answer choice C gives us an example of "cause without effect" - we are told that some animals, who would have presumably been exposed to the same microorganisms, did not become extinct. It's actually better than that, though, because answer C also strengthens the alternate cause, hunting, by showing that where that cause was absent (animals that were not hunted) the effect (extinction) was also absent. By strengthening the alternate cause we also weaken the proposed cause. It's a two-fer answer!

Hope that helps. Best of luck!


So when given Very few species of North American animals not hunted by the new arrivals from Asia were extinct 2,000 years after the first migrations are you supposed to assume from the information that most species were hunted? (by the way, I thought that because this isn't allowed in Must Be True questions, this shouldn't be allowed here as well)

So is this a different approach from the one Adam mentioned above? What are your thoughts on this?
akanshalsat
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The premise says: "It is implausible that hunting could have had such an effect" which is the premise, and C points to Hunting being the cause of the extinction - so are we not here attacking the premise? which is something we shouldn't do? as in we should believe in the truth of the premises given by the arguments and think of conclusions as suspicious?
Michaeltinti22
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I understand on BR why C is correct; I'm just now trying to fully understand why D is wrong (other than the fact that C is clearly better). Is it because 1.) "individual" animals would have very little impact on the survival of the species in general, and 2.) we'd have to assume that the animals attributed with extinction via microorganism fall under the category talked about in D?