Logical Reasoning

PT101 · S2 · Q16 The answer to which one of the

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

The authors of a recent article examined warnings of an impending wave of extinctions of animal species within the next 100 years.

Conclusion

They are wrong rephrase: There is some evidence that the rate of extinction of animal species is accelerating.

Evidence

13 species of fish were lost from 1900-1950, while 27 were lost from 1950-2000.

Evaluate

In order to argue that the rate of extinction is accelerating we need a comparison between the current rate of extinctions and the previous rates of extinctions.

We know that during the 1900's the rate of extinction among North American fish is accelerating (the last fifty years are worse than the previous fifty years).

But how many did we lose in the 1800's? More or less than 40? If we lost more than 40 North American fish species in the 1800's and only 40 in the 1900's, then the rate of extinctions is not accelerating for them.

Furthermore, why are we only talking about North American fish? When we talk about the rate of extinctions of animal species, we're talking about ALL species, not just fish.

Goal

Look for an answer comparing , or for an answer comparing "North American fish to other species".

On Evaluate, we want to pick an answer choice whose question can be answered in a way that weakens the argument.

So we'll pick whatever answer choice we could answer in a way that helps us argue .

16.

The answer to which one of the following questions would contribute most to an evaluation of the argument?

  1. Correct

    Were the fish species and

    Why this is right

    If we say, "Yes, the North American fish that went extinct in the 1900s were unrepresentative of animal species in general with regard to extinction", then we can undermine the generalization the author is making as he goes from evidence to conclusion. His evidence is about North American fish, but his conclusion is about the extinction rate of all animal species. Even if North American fish had an accelerating rate of extinctions in the 1900s, if all other animal species didn't have that accelerating rate, then the author's conclusion is super dubious. It's be like saying, "The price of Pop Tarts has gone up; therefore the price of items in the grocery store overall has gone up." What if Pop Tarts are the exception and all the other items are selling the same or worse than before?

    Skill tested: Evaluate · how this choice captures the argument's function is the move to repeat next time.

    75% picked this

  2. How numerous were the populations

    Irrelevant Distinction

    It doesn't matter what number we answer this question with. It won't change the fact that these species went extinct. The author's argument is just about the rate of extinctions, and clearly 27 in the last fifty years is a bigger number than 13 in the previous fifty.

    13% picked this

  3. Did any of the species

    Irrelevant Quality

    Whether we say yes or no, it doesn't change the fact that these species went extinct, which is all the author's argument cares about. We know and accept that the rate of extinctions among North American fish species is increasing. What we don't know is whether the rate of extinctions for animal species overall is increasing, and this answer doesn't discuss any other animal species.

    3% picked this

  4. What proportion of North American

    Weaker Impact

    It doesn't matter what percentage we supply as an answer. We might think a high number like "90% of the species that were endangered in 1950 are now thriving" weakens the argument by making it seem like North American fish are actually doing a lot better now than the author is portraying. But ultimately the argument only cares about extinctions, not whether they're thriving vs. endangered. No matter how much better these North American fish species would be doing, it won't change the fact that the rate of extinctions for North American fish species accelerated during the 1900s. It might help us argue that the 2000s are going to be a better century for North American fish species, but this is a weaker objection we get than with (A).

    7% picked this

  5. Were any of the species

    Irrelevant Quality

    It doesn't matter what traits the now-extinct species had. All the author's argument cares about is that the rate of extinction increased over the 1900s. Whether they were important or beautiful or delicious or any other trait is irrelevant to the claim we're discussing about rate of animal extinctions.

    3% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free