LSAT Explanation PT 22, S2, Q22: Biologist: Some speculate that the unusually

LSAT Question Stem

The biologist's view, if true, provides the most support for which one of the following? 

Logical Reasoning Question Type

This is a Must Be False question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

This LSAT problem presents a Must Be True (MBT) question type, which asks us to identify the answer choice that is most supported by the information provided in the passage. The passage presents two different explanations for the high frequency of small goats in island populations: 1) evolutionary pressure to ensure a diverse gene pool, and 2) greater reproductive success of small goats. The biologist supports the second explanation, stating that only reproductive success can influence the frequency of a trait in a population. Now let's analyze each answer choice:

a) The evolutionary pressure to ensure a diverse gene pool could have the effect of increasing the frequency of a gene for small size.

This answer choice aligns with the first explanation, which the biologist is arguing against. Since the biologist's view supports the second explanation (greater reproductive success of small goats), this answer choice does not receive support from the biologist's view and is incorrect.

b) The unusual frequency of small goats in island populations is not a result of the greater reproductive success small goats possess when space is limited.

This answer choice contradicts the biologist's view, which states that the greater reproductive success of small goats is the cause of the high frequency of small goats in island populations. Therefore, this answer choice is incorrect.

c) Contrary to what some believe, large goats achieve greater reproductive success than small goats even when space is limited.

This answer choice, if true, would not support the biologist's view and would present a paradox because smaller goats are more frequent in island populations. It does not align with the biologist's argument that the greater reproductive success of small goats is the cause of their high frequency in island populations. Thus, this answer choice is incorrect.

d) The evolutionary pressure to ensure a diverse gene pool does not have the effect of increasing the frequency of a gene for small size.

This answer choice is consistent with the biologist's view, which supports the idea that greater reproductive success of small goats, rather than evolutionary pressure for a diverse gene pool, is the cause of the high frequency of small goats in island populations. By stating that the evolutionary pressure for a diverse gene pool does not increase the frequency of a gene for small size, this answer choice aligns with the biologist's argument and is the correct answer.

e) A diverse gene pool cannot be achieved in a goat population unless the average size of its members is reduced.

This answer choice is irrelevant to the question of whether evolutionary pressure could have led to the size reduction in goats. It does not align with the biologist's view, which focuses on the greater reproductive success of small goats as the cause of their high frequency in island populations. Therefore, this answer choice is incorrect.

In summary, the correct answer is (d) because it aligns with the biologist's view and is supported by the information provided in the passage.