PrepTest 150

[lcid:3696] Prep Test 150 LSAT — Reading Comp — S1 Reading comp

Passage

Questions 20-27  .       It might reasonably have been expected that the  . adoption of cooking by early humans would not Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • Old belief (cooking didn't change our anatomy) vs. new belief (our anatomy evolved to require cooking)
  • Views, minor Meta-Structures, and the author's attitude
    • Old view:
      • Cooking didn't lead to any anatomical changes because cooking doesn't require adaptations (first and second sentence)
      • Cooking didn't affect our evolution because the practice is too recent (sixth sentence)
    • New view
      • We can only subsist on raw food in unusual circumstances, which suggests we evolved to need cooking to consume high-calorie diets efficiently (third, fifth, eighth, and last sentences)
      • There's evidence of cooking 250,000 years ago, so cooking is ancient enough to affect our anatomy (seventh sentence)
    • Example of a rare situation in which we could subsist on a raw diet:
      • Relatively sedentary lifestyle in a well-supported urban environment (third sentence)
    • Cause-and-effect relationship:
      • Cooking caused humans to consume high-calorie diets efficiently (eighth sentence)
      • Natural selection for the humans who used high-calorie diets efficiently caused an inability to survive on raw-food diets (last sentence)
    • Author's attitude: "might reasonably have been expected" (first sentence); "Important theoretical obstacles" (fourth sentence); "so evolutionarily constrained" (fifth sentence); "appears to be wrong" (sixth sentence)

Paragraph 2

  • Paragraph note
    • Hypothesis: Cooking led to smaller tooth and jaw size
  • Views, minor Meta-Structures, and the author's attitude
    • Cause-and-effect relationships, according to the author:
      • Cooking caused smaller tooth and jaw sizes about 100,000 years ago (second through fourth sentences)
      • Also possible that the evolution of Homo ergaster 1.9 million years ago caused smaller tooth and jaw sizes, and new cooking techniques like boiling caused the reduction of tooth and jaw size 100,000 years ago (fifth and last sentences)
    • Author's attitude:
      • "Important questions" (first sentence); "we suggest" (third sentence); "brodly explicable" (fourth sentence); "also posssible" (fifth sentence); "may prove" (last sentence)

Paragraph 3

  • Paragraph note
    • Hypothesis: Cooking led to a different digestive system
  • Views, minor Meta-Structures, and the author's attitude
    • Comparison:
      • Humans' digestive systems are different from other great apes, traditionally explained as an adaptation to a diet high in raw meat (second sentence)
      • Examples of differences between human and ape digestive systems:
        • Humans have smaller guts, longer small intestines, and smaller colons than other great apes (third sentence)
      • Cause-and-effect relationship, according to the author:
        • A high-calorie diet caused the differences in humans' digestive systems (fourth sentence)
        • Therefore, cooking may have caused the differences in humans' digestive systems (fifth sentence)
      • Author's attitude: "harder to reconstruct" (first sentence); "may therefore be at least as well explained" (fourth sentence); "therefore warranted" (last sentence)

Main Point: Current evidence suggests that cooking changed humans' evolutionary history and led to an inability to survive on a raw-food diet in most circumstances.

Key Lines?

Paragraph 1, Sentences 8-9 (P1, S8-9) - Author's central hypothesis

P2, S3 - Author's sub-hypothesis #1

P3, S4 - Author's sub-hypothesis #2

Meta-Structure?

Proposing a Hypothesis: We think this passage best fits the Proposing a Hypothesis Meta-Structure. In such a passage, the author typically makes a prediction or offers an untested explanation of a phenomenon*. The author might also posit questions that need to be addressed before the explanation can be accepted or rejected.

This passage follows this progression closely. The author relays some recent evidence that has overturned old beliefs about cooking and the human anatomy before offering the central hypothesis: cooking changed humans' evolutionary history and led to an inability to survive on a raw-food diet in most circumstances (P1, S5-9). The author uses the remaining paragraphs to describe two sub-hypotheses. The author thinks that cooking may have caused smaller tooth and jaw sizes (P2, S3) and changed the human digestive system (P3, S4). The author also describes some questions that still need to be addressed (P2, S6; P3, S5).

In a Proposing a Hypothesis passage, the main point is generally the author's central hypothesis. This author summarizes the central hypothesis at the end of the first paragraph. We further condensed that main point to: "Current evidence suggests that cooking changed humans' evolutionary history and led to an inability to survive on a raw-food diet in most circumstances."

*Some test-takers may believe this is a Phenomenon/Explanation passage. Such a designation would be OK if they didn't conclude that the author is certain of the explanations in this passage. Typically, we want to reserve the Phenomenon/Explanation Meta-Structures for passages that describe one or more tested explanations that have been accepted or rejected. Note how, in this passage, the author qualifies the explanations with phrases that reveal the explanations have not yet been fully tested or accepted ("we suggest" (P1, S9); "also possible" (P2, S5); "may prove to" (P2, S6); "may therefore be at least as well explained" (P3, S4)).

Causality: As is the case in many science-themed passages, Causality is the predominant minor Meta-Structure in this passage. In fact, the author's main point is causal: cooking caused changes in humans' ability to subsist on raw food. When the main point is causal, we can expect several other causal premises to bolster that main point. We've summarized all the cause-and-effect relationships in the Passage Summary. However, to answer questions quickly and confidently, it's helpful to understand the three central relationships:

  • Cooking caused humans to eat high-calorie diets efficiently, which caused an inability to subsist on raw diets (P1, S8-9)
  • Cooking may have also caused smaller tooth and jaw sizes around 100,000 years ago (P2, S3)
  • Cooking may have also caused changes in humans' digestive systems (P3, S4).

Last Thoughts?

Like the diet that cooking enabled, the first paragraph is dense and hearty. The author gives us a lot of information in that paragraph. If we didn't stop to consider how each of the pieces fit together, we may have had trouble understanding the rest of the passage, which would affect our ability to discern the main point, author's attitude, and Meta-Structure. If you had trouble understanding how the evidence about raw food and "earth ovens" related to the old beliefs about cooking and evolution or to the author's hypothesis, you may have read the first paragraph too quickly.

Remember, these passages want to convey a lot of information in as little space as possible. Each sentence has a vital role in the passage's overall argument. While we don't need to be an expert in every sentence, we should at least understand how the sentences form a coherent whole. If you had trouble appreciating the big-picture in this passage, consider slowing down and pausing to reflect on the passage's overall after each sentence or when you reach "pivot" words (like "However" in the third sentence or "Furthermore" in the sixth).

Question prompt

Which one of the Remaining source text redacted.
Why the credited answer is right

Credited answer: B

The notes below walk through why it fits the stem and how to eliminate the rest.

Question Type

Social Science

Strategy Overview

Review the sentence immediately before the parenthetical sentence in the first paragraph, determine weaknesses in that claim to anticipate how to improve it, and select the answer choice that makes the claim more convincing

Answer Anticipation

We'll approach Strengthen questions in Reading Comprehension similarly to how we would in Logical Reasoning. We can review the claim from the passage, just like we'd carefully read an argument in LR. We'll then interrogate the claim for any weaknesses since the correct answer on both RC and LR will probably strengthen the claim by fixing a problem. Additionally, causation flaws are commonplace on Strengthen questions in both RC and LR, so we'll be especially mindful of those.In this case, we're asked to strengthen the claim right before the parenthetical sentence in the first paragraph. In that sentence, the author says that the "widespread assumption that cooking could not have any impact on biological evolution because its practice is too recent appears to be wrong" (P1, S5). The author uses the next sentence to show why — we see evidence of the use of fire and "earth ovens" from 250,000 years ago (P1, S6).This argument isn't overtly causal, so we'll have to look for other issues. So, what's wrong with this argument? What does the author overlook? A few issues might come to mind.First, are we sure that 250,000 years is enough time for a practice to alter human evolution? What if our last known adaptation occurred more than 250,000 years ago? This would suggest that cooking, even if it is a 250,000-year-old practice, might be too recent to alter our evolutionary history. Therefore, the correct answer might fix this problem by declaring that 250,000 years is plenty of time for a biological adaption or that we have much more recent biological adaptions.Second, do we know that fire and "earth ovens" provide evidence of cooking? What if early humans used these ovens to make something else, like clay pots to store their raw food? In that case, we wouldn't even have recent evidence of cooking. The correct answer could fix this problem by confirming that the earth ovens were used for cooking.That said, many things could feasibly strengthen the claim that cooking isn't too recent a practice to impact humans' biological evolution. So, we should keep an open mind as we progress through the answer choices. We'll start by asking ourselves, "Does this make the claim that cooking isn't too recent a practice to impact humans' biological evolution more convincing?"

Answer choices

  1. A
    Evidence from cut marks Remaining source text redacted.
    Why choice A is not credited

    (A) Does this make the claim that cooking isn't too recent a practice to impact humans' biological evolution more convincing?

    No. This just provides evidence that hominid ancestors of early humans butchered animals. The test-writers want us to assume that this provides evidence that these ancient humans cooked animals, which would strengthen the author's contention that cooking is old enough to affect our biological evolution. However, this answer choice doesn't suggest that these hominid ancestors cooked the animals after butchering them. These ancestors may have butchered the animals for their raw meat, fur, or bones.

  2. B
    Human populations are estimated Remaining source text redacted.
    Why choice B matches the stem

    (B) Does this make the claim that cooking isn't too recent a practice to impact humans' biological evolution more convincing?

    Yes. This addresses one weakness we noted in the Answer Anticipation section — whether 250,000 years is enough time for a practice to alter human evolution. This answer choice shows that a biological adaptation to drinking animal milk can occur in 5,000 years. In other words, it shows that once we started drinking animal milk, it took 5,000 years before we developed a biological reliance on animal milk. In that case, 250,000 years should be plenty of time to become biologically adapted to cooked food. This strengthens the author's contention that cooking isn't too recent a practice to impact humans' biological evolution, and it is the correct answer.

  3. C
    Archaeological evidence indicates that Remaining source text redacted.
    Why choice C is not credited

    (C) Does this make the claim that cooking isn't too recent a practice to impact humans' biological evolution more convincing?

    Nope. This only says that humans used fire during the ice ages. The test-writers want us to assume that this provides evidence that humans cooked animals over flames even more than 250,000 years ago, strengthening the author's stance that cooking is an ancient practice. However, this answer choice does not support that assumption. We don't know when the last ice age occurred — perhaps it occurred less than 250,000 years ago. (In fact, the last glacial period began about 115,000 years ago and ended about 11,550 years ago.) Even if this answer choice referred to an ice age that was more than 250,000 years ago, it doesn't say that humans used fires to cook food. These humans could use fire for light and warmth exclusively.

  4. D
    An increase in the Remaining source text redacted.
    Why choice D is not credited

    (D) Does this make the claim that cooking isn't too recent a practice to impact humans' biological evolution more convincing?

    Negative. This just shows that early humans began eating more plant material. The test-writers want us to assume that this evidence shows that these humans were consuming cooked plants, since we know that cooking allows humans to consume more calories efficiently (P1, S7). However, such an assumption isn't warranted. These humans could simply have eaten more raw plants.

  5. E
    The fossil record indicates Remaining source text redacted.
    Why choice E is not credited

    (E) Does this make the claim that cooking isn't too recent a practice to impact humans' biological evolution more convincing?

    Nope. This is irrelevant to that claim. We're not strengthening the claim that we got smarter or grew bigger crania once we started cooking food.

What this tests

Discussion

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  • Why B? 1 reply

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