Logical Reasoning

PT11 · S2 · Q1 Sea turtles nest only

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

Sea turtles nest only at their own birthplaces.

Curious Fact

How do sea turtles find their way back to their birthplace, 15 to 30 years later, after having migrated away?

Hypothesis (i.e. Explanation)

Newborn sea turtles learn the smell of their birth environment, and it is this smell that stimulates the turtles to return to nest.

Evaluate

As soon as we see the question stem use the word "hypothesis", we know that this will fit the Explain Curious Fact pattern.

To weaken this hypothesis, we either need an Alternate Explanation for how the sea turtles find their way back to their birthplace, or we need to hurt the Plausibility of the idea that they smell their way back.

Goal

Let's find an answer that suggests an alternate explanation for how turtles navigate back to their birthplaces or that undermines the idea that their navigation is driven by the smell of their birth environment.

Which one of the following, if true, would cast the most serious doubt on the hypothesis in the passage?

Beaches on which sea turtles
No Impact
The seclusion of the beaches where turtles nest does not inform us about whether smell is the mechanism guiding turtles back to their birthplaces, or something else.
4% picked this
Sea turtles exposed to a
No Impact
This fact seems to suggest that sea turtles have an attraction to the environment where they were born. But we already knew that. After all, they return there after 15-30 years. We're trying to figure out how they find their way back, and this isn't weighing in on whether it's via smell or via some other mechanism.
9% picked this
Electronic tags attached to sea
No Impact
The fact that electronic tags do not alter nesting patterns doesn't provide any information about whether the turtles rely on smell or something else to return to their birthplaces.
1% picked this
Unlike other types of turtles,
Opposite Impact
This would lend plausibility to the hypothesis that the turtles smell their way home, which is the opposite of what we're trying to do.
1% picked this
Correct
Sea turtles that had their
Why this is right
If sea turtles that had their sense of smell destroyed still returned to nest at their birthplaces, it undermines the idea that smell is the key factor guiding them back. It's essentially an Effect w/o Cause weakener (they're able to find their way home even though they're not capable of smelling home).. This suggests that other mechanisms must be responsible for their navigational abilities, casting doubt on the hypothesis.
Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.
86% 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