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Zorluk: Çok zorCommand of Evidence: Textual

In zones of sympatry, where the breeding ranges of the indigo bunting (*Passerina cyanea*) and the lazuli bunting (*Passerina amoena*) overlap, the songs of male indigo buntings exhibit a distinct shift in frequency, diverging from those of lazuli buntings. Ecologist Dr. Ananya Sen hypothesized that this acoustic character displacement is driven solely by female mate selection—specifically, to avoid hybridization—rather than by male-male territorial competition. As evidence, Sen highlights playtests showing that sympatric male indigo buntings respond with equivalent levels of territorial aggression to playbacks of both species' songs, indicating that males do not use song frequency to differentiate between species during territorial defense.

Which finding, if true, would most directly weaken Sen's hypothesis?

  1. Sympatric male indigo buntings with song frequencies that diverge most widely from the lazuli bunting average spend significantly less time and energy defending their territories against male lazuli buntings than do those with less diverged songs.Cevap
  2. B
    Female indigo buntings in sympatric populations demonstrate a strong behavioral preference for males whose songs have diverged most significantly from the average song frequency of lazuli buntings.
  3. C
    In areas of allopatry, where the two species do not overlap, male indigo buntings exhibit higher levels of territorial aggression toward playbacks of their own species' songs than toward those of lazuli buntings.
  4. D
    The average song frequency of male indigo buntings in sympatry is highly consistent across different geographical territories, regardless of the local density of lazuli buntings.

Cevap

The finding that sympatric male indigo buntings with the most diverged song frequencies spend significantly less time and energy defending their territories against male lazuli buntings than do those with less diverged songs.
The correct option weakens the hypothesis by demonstrating a direct fitness benefit of song divergence related to male-male territorial competition. If males with more diverged songs spend less time and energy defending their territories from the other species, then the divergence reduces costly interspecific territorial disputes. This indicates that male-male competition is a key evolutionary driver maintaining the character displacement, directly challenging the researcher's claim that the displacement is driven solely by female mate selection.

Adım Adım Çözüm

1
Identify the core claim of Sen's hypothesis.
Sen's hypothesis is that acoustic character displacement (song divergence) in sympatric zones is driven solely by female mate selection to avoid hybridization, and not by male-male territorial competition.
To weaken the hypothesis, we need to find evidence suggesting that male-male territorial competition does play a role in driving or maintaining the song divergence.
2
Analyze the evidence provided by Sen.
Sen relies on playbacks showing equivalent male aggression toward both species, concluding that males do not use song frequency for species-specific territorial defense.
We must look for a finding that demonstrates a territorial advantage or function of song divergence for males, which would counter Sen's conclusion.
3
Evaluate the options for a finding that connects song divergence to male territorial defense benefits.
The correct option shows that males with more diverged songs spend less energy defending their territories against the other species, directly demonstrating a functional advantage of song divergence in male-male competition.
If diverged songs reduce interspecific territorial conflict, then male-male competition is a viable driver/maintainer of the displacement, directly weakening the 'solely female choice' hypothesis.

Anahtar Kavram

Identifying textual evidence that weakens an academic hypothesis or research claim.
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Konular

Command of Evidence: Textual

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