Logical Reasoning

PT143 · S4 · Q1 Among Trinidadian guppies

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Among Trinidadians guppies, males with large spots are more attractive to females than are males with small spots, who consequently are presented with less frequent mating opportunities.

Premise

Among Trinidadian guppies, large-spotted males attract more mates (good for procreation) but small-spotted males avoid predators better.

Premise

In waters with abundant predators, only small-spotted guppies live to maturity.

Anticipate

Large spots help with mating but, in dangerous waters, get the guppy killed before he can mate. So a trait that aids procreation (large spots) actually hinders procreation in some environments. The same trait helps and hurts depending on context.

Goal

An answer expressing this generalization: a trait helpful for procreation can hinder it in certain environments.

1.

The situation described above most closely conforms to which one of the following generalizations?

  1. A trait that helps attract

    Unsupported

    This says traits attractive to mates are sometimes more dangerous to one sex than another. The stimulus only describes male guppies' large spots — it doesn't compare risk to males vs. females. The stimulus doesn't support a generalization about sex-differential danger.

    2% picked this

  2. Those organisms that are most

    Unsupported

    The stimulus doesn't establish that the most attractive organisms have the greatest number of offspring. It only says they have more frequent mating opportunities — and even that is reversed in predator-heavy waters where the attractive males die young.

    0% picked this

  3. Those organisms that survive the

    Unsupported

    The stimulus says small-spotted guppies survive in dangerous waters, but it doesn't say survival correlates with greatest offspring count. Many factors affect offspring numbers; the stimulus only addresses survival.

    2% picked this

  4. Whether a trait is harmful

    Unsupported

    The stimulus only describes male guppies. It doesn't establish that traits are dangerous depending on which sex has them. It doesn't address what happens when females have spots, or any cross-sex comparison.

    1% picked this

  5. Correct

    A trait that is helpful

    Why this is right

    This is supported. Large spots help guppy procreation by attracting mates — but in predator-heavy environments, they hinder procreation by getting the male eaten before he can reproduce. So the very trait that helps procreation in some environments hinders it in others. The stimulus directly supports this generalization.

    Skill tested: Most Supported · how this choice captures the argument's function is the move to repeat next time.

    95% picked this

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