Logical Reasoning

PT17 · S3 · Q25 By examining fossilized beetles

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

By examining fossilized beetles, a research team has produced the most detailed description yet of temperatures in Britain over the past 22,000 years.

Goal of Procedure

Determine the maximum summer temperature that could have existed at a given location and period.

Procedure

The team selected and dated fossils of beetle species that still exist today.

They assumed that when several species dated to the same period were found together, the known modern temperature tolerances of those species could be used to infer the maximum summer temperature at that time and place.

Evaluate

We're not reading an argument here. We're just judging a Plan, so instead of skeptically thinking, , we're thinking,

If we see that species X, Y, and Z were all in the same place at the same time, and we know that X tolerates temps as high as 80 degrees, Y tolerates temps as high as 90 degrees, and Z tolerates temps as high 100 degrees, then we'll think .

How could this go wrong?

Goal

We might have a hard time predicting how to object to this plan, but we'll want an answer that, when negated, gives us a way to say,

25.

The procedure of the researchers assumes which one of the following?

  1. Beetles can tolerate warm weather

    Irrelevant Comparison

    This plan is just about calculating max temperature, so we're only discussing the beetles' heat tolerance. It doesn't matter whether they prefer cold, prefer warm, or like them equally.

    1% picked this

  2. Fossils of different species found

    Opposite (if anything)

    The method is not banking on the idea that if we find different species in the same place, they're from DIFFERENT periods. To the contrary, we are only hearing about how the method works when diff species in the same place are from the SAME period.

    5% picked this

  3. The process of dating is

    Irrelevant Comparison (other organisms)

    The argument does not compare the reliability of dating methods between species, so this is not required for the conclusion.

    3% picked this

  4. The highest actual summer temperature

    Opposite

    The way the method is described, they are taking the HIGHEST temperature tolerance and using that number, not averaging the different temperature tolerance numbers. In our example before (three species with tolerances of 80, 90, and 100 degrees), they would calculate 100 degrees as the max summer temp, whereas this answer is saying it should be 90 degrees, which is the average. So this answer would mean the method DOESN'T work. It would weaken.

    19% picked this

  5. Correct

    The temperature tolerances of the

    Why this is right

    This has that lovable Defender "not". When we negate this, it says that the temperature tolerances DID change significantly. So when we look at beetle species X, Y, and Z today and see that they tolerate 80 / 90 / 100 degrees respectively, we'd be failing to consider that 22,000 years ago they tolerated 70 / 80 / 90 degrees respectively. So using Z's modern tolerance of 100 degrees to calculate the max summer temperature 22,000 years ago would be giving us the wrong number!

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

    72% 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