Logical Reasoning

PT106 · S1 · Q5 The number of codfish in the North

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The number of codfish in the North Atlantic has declined substantially as the population of harp seals has increased from two million to more than three million.

Conclusion (therefore)

It is unlikely that the increase in the seal population has contributed significantly to the decline in the cod population.

Evidence

Cod plays a negligible role in the seal's diet.

Evaluate

This is an Anti-Causal argument because the author is saying .

GIVEN THAT seal barely eat any cod HOW CAN WE STILL ARGUE the increase in seals is a big cause of why the cod population is shrinking?

Maybe they don't eat cod, but the seals scare the cod away, or spread a disease to the cod, or disrupt the cod's habitat or food supply.

Goal

Let's find an answer that suggests a reason why the increasing seal population might still affect the cod population despite not preying directly on cod.

5.

Which one of the following, if true, most seriously weakens the argument?

  1. People who fish for cod

    Opposite Impact

    If more seals mean that cod fishermen are inconvenienced, that would be GOOD for the cod. The fishermen are one of their predators. So this answer tells a story where more seals leads to more cod. We need a way to argue that more seals is leading to less cod.

    4% picked this

  2. Water pollution poses a more

    Irrelevant Comparison / Opposite (if anything)

    We need a storyline for how more seals is leading to less cod, and this is telling us "water pollution is actually more likely harming cod".

    2% picked this

  3. The harp seal thrives in

    Opposite (if anything)

    We want a story where more seals leads to less cod, and this answer is basically saying, "they wouldn't even hang out in the same water".

    2% picked this

  4. Correct

    Cod feed almost exclusively on

    Why this is right

    This suggests an indirect dietary link: harp seals eat capelin, which is what cod also primarily feed on. If the increase in seal population leads to competition for capelin, it indirectly impacts the cod population, giving us a way to argue that seals ARE significantly contributing to cod decline.

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

    83% picked this

  5. The cod population in the

    Opposite

    Choice E provides a timeline issue: if the cod decline began before seal numbers increased, the seal population growth is unlikely to be a contributing factor, which strengthens the conclusion that the seals aren't responsible for the decline in cod.

    9% picked this

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