Logical Reasoning

PT144 · S3 · Q12 In a study of tropical forests

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In a study of tropical forests it was found that while the species of trees that is most common in a particular forest also reproduces the most, trees of the species that is rarest there tend to survive longer.

Given that ...

In tropical forests, the tree that is most common is also the one that reproduces the most.

How can it be that ...

In tropical forests, the tree species that is rarest is the species that survives the longest?

Evaluate

It's sort of hard to understand the intended paradox here, but they seemed to be going for the idea that we'd expect the most evolutionarily successful tree species to be, - most common - best at reproducing - best at surviving (live longest)

But the length of a species life span isn't really that intertwined with how much it reproduces or how thriving it is. Turtles live 100 years, but they are probably less numerous and reproduce less than squirrels.

Goal

Let's find an answer that distinguishes the rare tree and explains why it lives longer than these more common trees, that reproduce the most.

12.

Which one of the following, if true, most helps to explain why trees of the rarest species tend to survive longer than trees of the most common species?

  1. The species of trees that

    Deepens Paradox, if anything

    This answer helps us understand why the most common species in the forest thrives, but we don't need any help with the backstory on why a given species is the most common. We need an answer to help us understand why the tree species that is least common lives longest. The implicit contrast this answer provides is that, "trees of the rare species are worse-suited to the local climate". That's not a reason they would survive longer. That's more like the opposite.

    1% picked this

  2. Older trees tend to reproduce

    Weak Impact

    This seems a little tempting. We need to explain how the trees that are least common are the ones that live longest. This is connecting old age to low reproduction numbers, so the ideas are somewhere in the same vicinity. But this answer applies to all trees. All trees as they get older will reproduce less. Even these trees that are most common / reproduce the most will reproduce less when they are older. The less you reproduce, the more rare you would be as a species, but this answer isn't saying that "the species of trees with the longest life spans have the lowest reproduction rates". It's saying "older trees (of any species) reproduce less than younger trees".

    5% picked this

  3. The study tracked preexisting tree

    No Impact

    We don't care about any distinction between "preexisting" and "introduced" species. Whether a species was native or nonnative to an area, if it's successful enough to be the most common / most reproducing, then we'd probably figure that it also survives longer in that ecosystem. This doesn't give us a way to explain why the rarest species of tree is also the one that lives longest.

    0% picked this

  4. The survival of the trees

    Effect vs. Explanation

    This is telling us what ramifications there are when rarer species of trees survive. It's isn't explaining how / why the rarest species is able to survive longer than other tree species.

    2% picked this

  5. Correct

    The trees of the common

    Why this is right

    Not a great answer, but this at least helps to explain why trees of the rarest species live longer: they have less competition for resources. It's easier to thrive and survive when you have a stable food supply. Most importantly, it's the only answer choice besides (A) that points to a distinction between the common species and the rare species.

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

    92% picked this

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