Q9 - Members of large-animal species

[tamwaiman]

I don't know how to eliminate (C). Can someone explain?

(C) no small-animal species will become extinct unless some large-animal species also becomes extinct.
= IF small species extincts, some large will extinct as well.

Doesn't it indicate that the large species are more vulnerable to extinction than small species?

Thanks.

[giladedelman]

Thanks for posting!

It does indicate that larger species are more vulnerable to extinction than smaller species, but that doesn't mean that if any small species goes extinct, some large ones will too! By way of analogy, imagine that you are more susceptible to allergies than I am. Does that mean that if I have an allergic reaction, you are guaranteed to be having one as well? No! It just means that on average, you're more likely to have one.

(And hey, maybe we're not even allergic to the same things! Same with the animals in question: answer (C) says "when conditions deteriorate," but doesn't specify how. Maybe all the weevil-food disappears, but there are still bananas for the orangutans.)

(B), on the other hand, is supported, because the stimulus makes it clear that the amount of food a species requires affects its susceptibility to extinction: larger species are more at risk because they need way more food.

(A) is incorrect because "maximum population size" is totally out of scope, and we don't know what the main factor in excinction is. We just know size and food are factors.

(D) is incorrect because we only have information comparing the size of species as a whole; we have no idea whether individual members of the same species can be compared in this way.

(E) is incorrect because it could certainly the case that there's not enough food for anybody, large or small.

Does that answer your question?

[tamwaiman]

Hi giladedelman

I appreciate your reply and recognize (B) as the best now.
However, would you mind explain me more about "but that doesn't mean that if any small species goes extinct, some large ones will too!" ?

Because I just translate the LSAT logic from rule:
A unless/without B = IF ~A ---> B

Is there anything wrong?

[giladedelman]

My point was that (C) is unsupported; we have no basis to say that no small species will go extinct unless some larger ones do, too. You did translate it properly, though. So it's not that you have the wrong conditional statement, it's that that conditional statement is unsupported.

[maryadkins]

Here's my take on it

9. (B)
Question Type: Inference
We are told that when large animals are unable to find enough food, it makes them more vulnerable to extinction than small animals whose populations need less food. We can infer that the risk of extinction has to have something"”however small"”to do with how much food is available to animals. (B) correct choice.

(A) is incorrect. The stimulus tells us that not having enough food helps make them more vulnerable to extinction, not that it’s the main factor.
(C) is incorrect. Stating that large-species animals are more vulnerable is not the same as stating that every single large-animal that becomes extinct means a small one also does. Keep an eye out for extreme language that doesn’t match the stimulus.
(D) is incorrect. Like (A), we don’t know anything about whether food is "primarily" a factor, or not, only that it’s a factor.
(E) is incorrect. Be wary of how this choice twists the logic in the stimulus. Just because deteriorating conditions have a lesser effect on small animals does not mean they are A-OK. It just means what it says"”that they’re less susceptible to extinction than the large animals.

[marykatemoller]

Could (D) also be wrong because of a detail creep? The stimulus is speaking about the extinction of a species whereas answer choice (D) is speaking about the survival of an individual.

[ohthatpatrick]

Yeah, you're right about (D).

I think Gilad's original explanation took the same angle you were thinking. He said:
"D is incorrect because we only have information comparing the size of species as a whole; we have no idea whether individual members of the same species can be compared in this way."

There's definitely more than one problem with this answer.

[contropositive]

I elimated (D) because it talked about "any given species" but we only know about small & large animal species