Q19

[bermudask8er7]

Let me start off by thanking you. I've been a big fan of this board.

I don't completely understand why the answer is E. Is it because E suggests that fungi usually cannot successfully turn back toward parasitism (therefore cannot "evolve" toward parasitism)?

[ManhattanPrepLSAT2]

Glad to hear you like the board! It's fun for us to write answers for you all --

I think your understanding is right --

The assumption that the author criticizes is in lines 47 - 50 -- that over time parasitic relationships will become symbiotic (things evolve to work for the mutual benefit of one another) --

The specific criticism he makes is that mushrooms evolve to be both symbiotic and parasitic --

We know that evolution works through a weeding process -- those who develop certain traits survive, and those that develop other traits don't --

If we learn that mushrooms which evolve to being parasitic die off, that would significantly weaken how his criticism affects the assumption (because, as you said, they would not evolve, in general, to become parasitic).

[yoohoo081]

I'm still confused after reading the explanation.

Can you clarify why outside info on dieshortly after is relevant and why choiceA is wrong please?

[ManhattanPrepLSAT2]

I think (A) is most tempting if you misread the question stem.

We are looking for an answer that would weaken the author's criticism of the assumption, rather than weaken the assumption.

The initial assumption is that parasitic interactions evolve towards symbiosis.

The author states that they could evolve to symbiosis or parasitism.

Answer choice (A) , you could argue, weakens the original assumption, but it doesn't weaken the author's criticism -- if anything, it could strengthen it, by showing how wrong the initial assumption was.

I hope that helps clear up the issue, but please follow up if it doesn't, and I'll be happy to continue the conversation.

[yoohoo081]

Ah, I got it now.

THANK YOU MIKE FOR THE EXPLANATION!

I misunderstood the question stem like you said. I missed the "author's criticism o the assumption".

[adarsh.murthy]

But I think the question that was posted is still not answered:
"Can you clarify why outside info on dieshortly after is relevant ?"
The passage never says that turning back to parasitism must be "succesful". I think the word "easily" could be interpreted so as to apply to successful turn to parasitism. What do you think?

But, anyways I think this is the best option; as is the case with many lsat options, the option E is the one we can best rationalize .

[bbirdwell]

I think it helps to state this relevant pieces in explicit terms.

The assumption:
parasitic interactions INEVITABLY evolve to symbiosis

The author:
sometimes, parasites evolve to mutualism (symbiosis).

Our job is to weaken the author's position here.

(E) says, when parasites turn back to mutualism, they go extinct.

What does that mean? It means that INEVITABLY, parasitic interactions do evolve to symbiosis, because the ones that don't, die.

[T.J.]

Hey guys, thanks for the good work posted above.

Would you all agree that the difficulty of this question lies in the question stem, specifically "weakens the author's criticism of the assumption that ..."?

I had a hard time digesting what it means, but now I think I have clarified the meaning. The phrase "weakens the author's criticism of the assumption that ..." is the same as [strengthens the assumption that...]. The reason is because we could supposedly strengthen one's claim given that the criticism of that claim is weakened.

Following the logic, answering this question is like breeze. Let me know what you guys think.

[tommywallach]

Hey T.J.,

Yeah, that totally makes sense for me. It's basically a double negative in the form of a question! Good catch!

-t