PrepTest 143, Section 1, Question 9
Red admiral butterflies fly in a highly irregular(50 more words not shown)
Which one of the following,(10 more words not shown)
- ANo species of(13 more words not shown)
- BAttacks from predators(10 more words not shown)
- CMany other types(12 more words not shown)
- DIt is much(19 more words not shown)
- EAll of the(15 more words not shown)
Reading the argument
Why spend extra energy flying in such an unpredictable way?
Avoiding predators is one possibility. Imagine a bird trying to intercept a butterfly that keeps changing speed and direction. The bird could have trouble anticipating where it will go next. But perhaps the flight pattern serves some other purpose, such as attracting a mate. We need evidence to choose between those stories.
The scientists point out that red admirals aren't poisonous. Unlike butterflies that predators avoid eating, red admirals have to escape. That makes the evasion explanation plausible: an inefficient way to travel might still be useful if it keeps you alive.
What we’re looking for
We're asked to strengthen that explanation. I don't have a precise answer in mind yet. I'd want evidence linking the unusual flight specifically to the need to avoid predators, rather than simply more facts about butterflies.
Working the answers
- ACorrect
This gives us a useful comparison. Poisonous butterflies, which predators already avoid, don't have this irregular flight style. Red admirals lack that protection and do fly irregularly. That pattern fits the idea that the costly flight style serves as a way to escape predators. It doesn't prove the evolutionary explanation, but it supplies evidence connecting the behavior to the need for another defense.
- B
Predators don't have to be the leading cause of death for avoiding them to be useful. A danger can matter even when something else kills more butterflies. B doesn't provide the positive evidence connecting this flight pattern with predator avoidance that we're seeking.
- C
Other butterflies flying similarly doesn't tell us why they do it. Are those butterflies poisonous? Do they face the same need to escape predators? Without that connection, C establishes that the style is shared but doesn't support this explanation for it.
- D
A comparison with heavier insects doesn't explain the red admiral's behavior. Irregular flight could be less costly for a butterfly than for a beetle while still being an inefficient way for that butterfly to travel. We need evidence of the benefit that explains choosing it.
- E
The predators' broader diet doesn't establish what the red admiral's flight accomplishes. Knowing that the same predators also eat other nonpoisonous butterflies doesn't tell us whether irregular flying helps red admirals evade them.
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