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Zorluk: OrtaStrengthening or Weakening Author Assertions

Passage:
For decades, marine biologists assumed that the deep-sea gigantism observed in benthic invertebrates living in abyssal zones—such as giant isopods and amphipods—was primarily an evolutionary response to low ambient water temperatures, which slow metabolic rates and delay cellular maturation. According to this thermal-retardation model, delayed maturity allows organisms a prolonged growth phase, resulting in larger ultimate body sizes.

However, a recent study of abyssal scavengers near hydrothermal vents challenges this traditional explanation. Researchers observed that deep-sea species inhabiting areas surrounding hydrothermal vents exhibit body sizes comparable to those of their cold-water abyssal relatives, despite exposure to significantly higher localized water temperatures. The authors of the study assert that low ambient temperature is not the primary driver of abyssal gigantism; rather, they hypothesize that metabolic adaptation to severe food scarcity in the deep ocean selects for larger body mass, which stores energy reserves more efficiently and reduces mass-specific metabolic costs.

Which of the following, if true, would most seriously weaken the authors' assertion regarding the primary driver of abyssal gigantism?

  1. Abyssal scavengers residing near hydrothermal vents spend the vast majority of their lifespans in adjacent near-freezing waters, entering the warmer vent zones only briefly to feed.Cevap
  2. B
    Individual abyssal scavengers inhabiting regions with the most extreme food scarcity consistently grow larger than members of the same species in food-rich areas.
  3. C
    Shallow-water invertebrates exposed to artificially lowered temperatures in laboratory environments exhibit growth rates similar to those of abyssal invertebrates.
  4. D
    Hydrothermal vent ecosystems support significantly higher total biomass and population densities than the surrounding cold ocean floor.
  5. E
    The metabolic rates of abyssal species were originally measured by early marine biologists using imprecise pressure-chamber equipment.

Cevap

The statement that abyssal scavengers residing near hydrothermal vents spend the vast majority of their lifespans in adjacent near-freezing waters, entering warm vent zones only briefly to feed, most seriously weakens the authors' assertion.
The authors base their rejection of the thermal-retardation model on the observation that abyssal scavengers near warm hydrothermal vents still exhibit gigantism. If these scavengers spend nearly all of their lives in the cold waters surrounding the vents and only enter warm water briefly, their growth and maturation occur almost entirely under cold conditions. Thus, cold temperature could still be the primary driver of their gigantism, invalidating the authors' primary reason for discounting temperature.

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1
Identify the author's core assertion and premise.
Assertion: Low ambient temperature is not the primary driver of abyssal gigantism. Premise: Invertebrates living near warm hydrothermal vents achieve the same giant sizes as those in cold abyssal waters.
To weaken an assertion based on observational evidence, one must undermine the connection between the observation and the author's conclusion.
2
Evaluate how new information impacts the premise.
If the organisms near vents spend almost all of their lives in near-freezing waters, their environmental conditions are functionally cold, not warm.
Showing that the subjects were actually subjected to low temperatures removes the counterexample that the author used to reject the thermal-retardation model.
3
Select the option that undermines the author's rejection of the temperature model.
The option establishing that vent organisms spend nearly their entire lives in cold water invalidates the author's evidence and weakens their conclusion.
It shows that temperature retardation remains a viable explanation for gigantism even among hydrothermal vent species.

Anahtar Kavram

Weakening an Author's Assertion by Undermining Underlying Premises
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Konular

Strengthening or Weakening Author Assertions

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