Examkin

Question

Difficulty: HardCommand of Evidence: Textual

Marine biologist Dr. Teresa Rossi and colleagues investigated the acoustic behavior of humpback whales (*Megaptera novaeangliae*) during foraging. The team hypothesized that humpback whales modify the acoustic structure of their "feeding calls" to coordinate cooperative bubble-net feeding only when the local density of their prey (krill) falls below a specific threshold. According to the researchers, this acoustic modification serves to recruit conspecifics and organize group foraging to optimize efficiency under scarce resource conditions, whereas in areas of high prey density, whales forage individually without using these modified calls.

Which finding, if true, would most directly support the researchers' hypothesis?

  1. A
    Humpback whales in both high-density and low-density prey regions emitted unmodified feeding calls that attracted other marine mammals, such as seals, which then competed with the whales for the available krill.
  2. B
    Individual humpback whales that regularly forage in low-density krill regions show greater neurological development in brain regions associated with acoustic processing than whales that forage primarily in high-density regions.
  3. In areas where krill density was below the threshold, whales emitted modified feeding calls and engaged in cooperative bubble-net feeding, achieving higher per-whale prey capture rates than those foraging individually in the same areas, whereas in high-density areas, they did not emit modified calls.Answer
  4. D
    Whales in high-density krill regions frequently emitted modified feeding calls to initiate cooperative bubble-net feeding, but the large quantity of krill caused the bubble-nets to collapse, reducing the overall group foraging efficiency.

Answer

The correct answer is the option stating that in low-density krill areas, whales emitted modified feeding calls and engaged in cooperative bubble-net feeding to achieve higher prey capture rates, while not emitting them in high-density areas.
The correct option directly supports the hypothesis by demonstrating that the modified calls occur only under low prey-density conditions and that they lead to cooperative bubble-net feeding, which is more efficient (resulting in higher per-whale capture rates) than foraging individually in those same conditions. It also confirms that whales in high-density regions do not emit the modified calls, matching the researchers' observation.

Step-by-Step Solution

1
Identify the researchers' primary hypothesis in the passage.
The hypothesis is that humpback whales modify their feeding calls to coordinate cooperative bubble-net feeding only when prey density is below a specific threshold, optimizing foraging efficiency under scarce conditions, while foraging individually without these calls under high-density conditions.
Understanding the precise elements of the hypothesis is necessary to determine what evidence would support it.
2
Evaluate the evidence required to support this multi-part hypothesis.
The supporting evidence must demonstrate: (1) calls are modified only when prey density is low (below the threshold); (2) these calls coordinate cooperative bubble-net feeding; and (3) cooperative feeding under these scarce conditions is more efficient than individual feeding.
A complete support must address all components of the researchers' proposed mechanism.
3
Compare the options to find the one that matches these criteria.
The option describing whales in low-density areas using modified calls for cooperative feeding with higher per-whale capture rates (and no modified calls in high-density areas) fits all criteria perfectly.
This option provides direct empirical support for both the conditional nature of the calls and their cooperative, efficiency-optimizing function.

Key Concept

Command of Evidence: Textual
Estimated Time:2m 0s
Rate this question

Topics

Command of Evidence: Textual

More questions from this topic