LSAT 107 – Section 3 – Question 22

LSAT 107 - Section 3 - Question 22

October 1999

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT107 S3 Q22
+LR
+Exp
Most strongly supported +MSS
A
33%
164
B
5%
161
C
2%
159
D
55%
169
E
5%
160
154
164
174
 +Hardest 148.579 +SubsectionMedium

Biologist: Some speculate that the unusually high frequency of small goats found in island populations is a response to evolutionary pressure to increase the number of goats so as to ensure a diverse gene pool. However, only the reproductive success of a trait influences its frequency in a population. So, the only kind of evolutionary pressure that can reduce the average size of the members of a goat population is that resulting from small goats achieving greater reproductive success than their larger cousins.

Summary

The biologist refutes the view that the high frequency of small goats on islands is due to evolutionary pressure to increase the number of goats. Why is this wrong? The only way a trait can increase in frequency is through reproductive success, Therefore, the only evolutionary pressure that could cause this phenomenon is small goats achieving greater reproductive success.

Strongly Supported Conclusions

The biologist considers the speculations she refers to to be incorrect.

Small goats have greater reproductive success in island populations than larger goats.

Ensuring a diverse gene pool does not qualify as evolutionary pressure.

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

Anti-supported. The biologist refutes this point. She says only reproductive success would qualify as evolutionary pressure.

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.

Anti-supported. The biologist claims that the only thing that can reduce the average size of the population is greater reproductive success for small goats. This may or may not be due to the small space.

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

Unsupported. There is no support for the actual reproductive success rates by goat size. The biologist is advocating the point that the smaller goats must achieve greater reproductive success in order to decrease the average size of the goats.

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.

Strongly supported. The author dismisses this claim on the grounds that it does not impact reproductive success, the only way to influence frequency. Therefore, ensuring a diverse gene pool cannot have the effect of increasing the frequency of the gene for small size.

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

Unsupported. There is no information as to how a diverse gene pool can or cannot be achieved. That was only part of a theory that was dismissed.

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LSAT PrepTest 107 Explanations

Section 1 - Logical Reasoning

Section 2 - Reading Comprehension

Section 3 - Logical Reasoning

Section 4 - Logical Reasoning

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