Q18

[zainrizvi]

Hmmm... bit of an interesting question here. I'm primarily concerned with choices (C) and (E).

At first, C seems plausible -- there is a correlation which supports one of the other hypothesis. The only shortcoming of this choice is that it just shows a CORRELATION -- a more solid causation would be needed for this to be a valid answer choice.

E seems plausible too.. but I'm concerned with the fact that the answer choice only targets 1 aspect of the relationship (i.e. rate of extinction in tropical) versus targeting the entire relationship (i.e. rate of extinction in tropical AS COMPARED to rate of extinction in arctic) -- I am sure I have done questions in the past where this has been a trap answer choice. Who cares if "most" species end up dying in tropical area, as long as this rate is higher than the rate in the arctic?

Is there some other justification that I am missing? Or is this just a bad question?

Thanks!

[tommywallach]

Hey Zain,

This is a great question. Actually, it's a bit like an LR Weaken question. For funzies, let's solve it that way:

Conclusion: Regional speciation is the reason there are more species in the tropics

Premises: Subgroups generally develop at the edges of a geographical area, and tropical areas are more friendly to new isolated subgroups.

We want to weaken this argument.

(A) This doesn't weaken anything. In fact, the final paragraph tells us that this does happen.

(B) Again, this is supported by the passage. Tropical areas are able to support many species on the same resources.

(C) As you pointed out, the key word here is correlation. Correlation is something we already have (i.e. this is a premise booster). We already know that higher energy places seem to have larger populations/less extinction (generally). The question is what's causing this to happen?

(D) This is totally useless. Who cares about "undiscovered" species?

(E) Take a look back at our premise. We were told that tropical areas were friendly to new isolated subgroups. Suddenly, it seem like they're unfriendly. "Rapid extinction" is a serious problem!

The most important thing to note here is that (E) is simply more likely to be the answer than (C). What (C) does is it tries to ignore the rate-of-speciation hypothesis entirely, by simply saying "Maybe one of those other theories is good." But the LSAT doesn't do that. The correct answer should relate directly to the science of the rate-of-speciation (which requires much better reading on your part!).

Hope that helps!

-t