Reading comp PrepTest 127 · Section 4 · Question 13

Passage

Questions 8-15  .        Mechanisms for recognizing kin are found  . throughout the plant and animal kingdoms, regardless  . of Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • A question (why do organisms recognize kin?) and one answer (inclusive fitness theory: help relatives to increase genetic representation)
  • Views, minor Meta-Structures, and the author's attitude
    • Inclusive fitness theory proponents' view:
      • Organisms pass on genes through offspring and relatives, so recognizing kin allows the organism to help its relatives and increase its genetic representation (fourth and fifth sentences)
    • Comparison, according to the author:
      • Traditional evolution says that natural selection favors individuals that produce the most offspring, while inclusive fitness theory says that natural selection favors organisms who help their relatives (fifth sentence)
      • But in both cases, natural selection favors these individuals because they increase the organisms' total genetic representation (fifth sentence)
    • Example of phenomena inclusive fitness theory has helped explain, according to the author:
      • The evolution of the honeybee and other social insects, most of which do not produce offspring (last sentence)
    • Author's attitude: "helped to explain previously mysterious phenomena" (last sentence)

Paragraph 2

  • Paragraph note
    • Inclusive fitness theory applied to mysterious cannibal behavior (spadefoot tadpole example, who can become cannibalistic but avoid kin, unless really hungry)
  • Views, minor Meta-Structures, and the author's attitude
    • Author's view:
      • Inclusive fitness theory has been useful in explaining findings on cannibalistic behavior (first sentence)
    • Example of application of inclusive fitness theory to cannibalism, according to the author:
      • Spadefoot toad tadpoles can become cannibalistic but only eat nonrelatives (unless really hungry) (third through last sentences)
    • Cause-and-effect relationships, according to the author:
      • A spadefoot tadpole eating a shrimp or another tadpole causes the tadpole to become larger and entirely carnivorous (fifth sentence)
    • Author's attitude: "applied usefully" (first sentence); "obvious" (second sentence); "suggests" (seventh sentence); "offers at least a partial answer" (seventh sentence); "Interestingly" (last sentence); "apparently" (last sentence)

Paragraph 3

  • Paragraph note
    • Alternative answer (avoiding bacteria, tiger salamander larvae example)
  • Views, minor Meta-Structures, and the author's attitude
    • Author's view:
      • Some organisms, like the tiger salamander, may recognize kin to avoid deadly diseases (first and last sentences)
    • Example of an organism that recognizes kin to avoid deadly diseases, according to the author:
      • Tiger salamander larvae sometimes become carnivorous; a deadly bacterium spreads more easily among relatives, so it's safer to eat nonrelatives (second through fourth sentence)
    • Author's attitude: "may be other reasons" (first sentence); "suggests" (fourth sentence); "may favor" (fourth sentence); "can be explained simply" (last sentence)

Main Point: The inclusive fitness theory can explain some instances of kin recognition, but alternative explanations seem to fit other organisms better.

Meta-Structure?

Question/Answer: This passage best fits the Question/Answer Meta-Structure.* In such a passage, the author poses a question early on and uses the rest of the passage to answer that question. That's what this author did. The author asked why so many organisms are able to recognize their kin, irrespective of how complex that organism is. The author provides two possible answers: the inclusive fitness theory and the ... well, the second one isn't given a name, so we'll call it the don't-eat-your-kin-and-die theory.

When a passage uses a Question/Answer Meta-Structure, the main point is generally the answer the author agrees with. The author is open to both answers in this passage (though the author comes just short of fully endorsing either), as the author suggests that both explanations may apply to different organisms. So, we made sure our anticipated main point reflected the author's noncommittal stance.

*That said, you could definitely call this a Phenomenon/Explanation. After all, there is considerable overlap between the Question/Answer and Phenomenon/Explanation Meta-Structures. The author called the issue of kin recognition a "question" in the first paragraph (P1, S2-S3), so we went with Question/Answer. If you went with Phenomenon/Explanation, you'd wind up with the same understanding of the passage's organization and main point.

Example: There are two major examples in this passage, making the example the most prominent minor Meta-Structure in this passage. In fact, at least one example is provided for each explanation of kin recognition. The inclusive fitness theory is explored through the second half of the first paragraph and the second paragraph, both of which have an example (bees/social insects in the first paragraph, cannibal tadpoles in the second paragraph). The "self-preservation" explanation is presented in the third paragraph via an example of a tiger salamander larva. We should expect a few questions on these examples.

Last Thoughts?

There were a lot of details and a lot of science in each paragraph, so we're going to have to rely heavily on the passage's language to help us with the more technical questions. It will be important, therefore, to know what type of information is in each paragraph so that we can quickly orient around the correct one for each question. So, we'll rely heavily on our notes for this passage.

Question prompt

The passage states which 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

Science

Strategy Overview

Remind ourselves of the main point of the passage, then head to the answers, focusing on those that line up with the main point and then using our notes/the passage to find the correct answer

Answer Anticipation

The topic of this question stem matches the topic of the passage as a whole, so there's not much guidance as to where the correct answer is going to show up. As such, we'll need to rely on our big-picture understanding of the passage to answer this question. We should start by reminding ourselves of the main point (either by reviewing what we said after reading the passage or by rereading our answer to the main point question). From there, we can head to the answer choices. If something in an answer choice doesn't seem familiar and isn't reflected in our notes on each paragraph, we shouldn't check the passage to see if it was mentioned. Instead, we'll table it and move on to the next answer choice. If something seems inconsistent with the main point, we can eliminate it. If something seems familiar, consistent with the main point, or reflected in our notes, we'll use our notes/highlights/underlines to find the part of the passage that proves the answer choice must be true. If we can find that confirmation, we'll select that answer choice and move on.

Answer choices

  1. A
    The mechanisms are most Remaining source text redacted.
    Why choice A is not credited

    (A) Is this consistent with the main point or reflected in our notes?

    Nope. This answer choice doesn't line up with our big-picture understanding of the passage. The author brought up two explanations and showed that each explains the behavior of a different species, so assuming they all have a similar purpose in all species would not "most easily" explain the phenomenon. Since this answer choice contradicts the main point, we can eliminate it without reviewing the passage.

  2. B
    The mechanisms have become Remaining source text redacted.
    Why choice B matches the stem

    (B) Is this consistent with the main point or reflected in our notes?

    Yes! This passage is all about investigating the "purpose" that mechanisms for kin recognition "serve," so it's fair to say that there is interest in this topic! Therefore, it's worth checking the passage to see if this is supported.

    This is the type of background info we generally see at the beginning of a Question/Answer (or Phenomenon/Explanation) passage before the author gets to the answer (or explanation). Checking the beginning of the passage, we see that the second sentence explicitly supports this answer choice: "Improvements in the general understanding of these mechanisms have turned some biologists' attention to the question of why kin recognition occurs at all" (P1, S2). Therefore, we can select (B) and advance straight to the next question.

  3. C
    The mechanisms have become Remaining source text redacted.
    Why choice C is not credited

    (C) Is this consistent with the main point or reflected in our notes?

    Nope. Neither the main point nor our notes mention when people began focusing on the theory behind kin recognition. Therefore, we should curb any desire to review the passage and table or eliminate (C).

    Besides, we wouldn't find any support for this answer choice even if we re-read the entire passage. Scanning the passage for a date, we can find the 1960s mentioned in the first paragraph. However, that's tied to when inclusive fitness theory was proposed (P1, S3), not when the mechanisms for kin recognition first became the focus of theoretical attention. People could have been paying attention to the theory behind kin recognition before inclusive fitness theory was proposed!

  4. D
    The detailed workings of Remaining source text redacted.
    Why choice D is not credited

    (D) Is this consistent with the main point or reflected in our notes?

    Nope. Neither the main point nor our notes say that we need to understand the mechanics behind kin recognition before we can understand their purposes. In fact, the author's main point suggests that we're beginning to understand some purposes reasonably well. Moreover, this answer choice uses bold SCOTUS language ("must") that's hard to support and thus unlikely to appear in the correct answer to a Must Be True question. Therefore, we should curb any desire to review the passage and table or eliminate (D).

    Besides, we wouldn't find any support for this answer choice even if we re-read the entire passage. The author never states that an incomplete understanding of the mechanisms is what's holding us back from having better answers about the purpose of kin recognition. Whether the tadpoles take a nip to sense a protein or a pheromone doesn't seem to explain why they've developed a means of recognizing their kin.

  5. E
    The mechanisms operate differently Remaining source text redacted.
    Why choice E is not credited

    (E) Is this consistent with the main point or reflected in our notes?

    No. Neither the main point nor our notes mention two species that use kin recognition for the same purpose. Spadefoot toads use it to allow their kin to survive, while tiger salamanders use it to protect themselves. Therefore, we should curb any desire to review the passage and table or eliminate (E).

    Besides, we wouldn't find any support for this answer choice even if we re-read the entire passage. We don't even learn anything about how the mechanism works in tiger salamanders, so we don't even know if they also use the nip-and-release method that is seen in the tadpoles! This comparison is unsupported by the passage, so we can rule it out.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A 7%
  2. B Credited 41%
  3. C 3%
  4. D 16%
  5. E 33%

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Discussion

  • Confused 2 replies

    Started by @chris_va

  • Why B 1 reply

    Started by Meredith

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