Q8 - For a species of large abalone shellfish

[mshinners]

Question Type:
Explain a Result

Stimulus Breakdown:
Expected: Abalones will develop into bigger ones when there's a lot of food and fewer predators.
Unexpected: Abalones tend to develop into bigger ones when otters—a predator—move into their area.

Answer Anticipation:
The stimulus establishes two factors in the growth: food and predation. The stimulus states that there are predators around, so the correct answer will probably connect the otters helping the abalones get food, the other factor.

Correct answer:
(C)

Answer choice analysis:
(A) Opposite, if anything. If otters are eating the abalones and the rest of the food, it's hard to see how the abalones would develop into the bigger models.

(B) Out of scope. There were abalones that grew despite the increased predation, and there being other abalones that we don't know anything about doesn't explain what happened to the ones we do.

(C) Shazam. Otters make it easier for the abalones to get food, the other factor in their development. While I wouldn't pick this on the first pass since it still means the otters are around, we already know that the otters are correlated with the growth, so it's less of an issue since it's a given.

(D) Out of scope/relative. "More rapidly" doesn't guarantee it's fast enough to develop. Also, the stimulus talks about small abalones developing into large ones, so their relative mating speed doesn't explain how that process happens even in the presence of a predator. If anything, this would explain why the large abalones would have trouble fully developing in an area with otters (the ones that stayed small would out-produce the ones that started developing into bigger ones).

(E) Out of scope. The fossil record shows that otters moved in before the development of the large abalone. Their preferences don't explain how that resulted in the small ones getting big.

Takeaway/Pattern:
Be clear on what you're trying to explain here. Also, if the stimulus brings up multiple factors but only addresses one of them, the answer will almost certainly address the other.

#officialexplanation

[StephanieK821]

I ended up choosing the correct answer choice (c) for PT 80, Section 1, Question 8 by process of elimination; but I spent a lot of time because my expected component of the stimulus breakdown was that abalones will develop if they focus more on mating than food and predators. Therefore, I anticipated that the answer choice would connect otters to helping the abalones mate. Was my breakdown and answer anticipation incorrect? Thank you!

[ohthatpatrick]

Yeah, it's possible that your breakdown was just a little too narrow.

3 pressure points were identified, so we'd have to cast a wide net, since any of them affect the likelihood of a large abalone developing from a small one
- less energy on food
- less energy avoiding predators
- more competition mating

If the influx of otters made any of those three happen, it will contribute towards making large abalone more likely.

They could have written a correct answer that dealt with "less energy avoiding predators" as well.

f.e.
(A) Otters eradicate all other predators of abalone, and it's easier for abalone to avoid otters than to avoid their other predators.