#17 - In deep temperate lakes, water temperatures vary

[Administrator]

Please post below with any questions!

[roselsat123]

On the official exam, I answered correctly with E. I went through the test again and with blind review chose A. Can you please explain this stimulus?

[Kristina Moen]

Rose,

In the stimulus, you have four different time periods. In winter, cold water is at the top. In summer, cold water is at the bottom. The "turnover" (from top to bottom and vice versa) occur in fall and late winter. You can imagine the water cycling from top to bottom and back over a year period. Also, lake trout can be found in the coldest water. This information is the premise.

The last sentence gives us the conclusion. While lakes are partially iced over in late winter, Anglers looking for lake trout should avoid the trout's "summer haunts."

The key here is to understand the water temperatures.
Winter: Cold water on top
Late Winter: "Turnover" to cold water on bottom
Summer: Cold water on bottom
Fall: "Turnover" to cold water on top

The argument that in late winter, Anglers should avoid the summer haunts ASSUMES that turnover hasn't happened yet. If turnover had happened, we'd be at summer levels again, and so Anglers would want to look for trout at their summer haunts.

Whenever I see dates/time periods in an argument, I underline them or note them in my brain. Here, four time periods (winter, summer, late winter, and fall) are mentioned. And the conclusion is specifically about late winter.

Hope that helps.

[lyujenny]

I chose E when I was reviewing this question after a practice test, but I was also considering C because of the idea that if you negate it to “lake trout are not found exclusively in deep temperate lakes” it would weaken the argument as it says that the “best” thug to do is to eschew the lake trout’s summer haunts — if lake trout is found in areas other than deep temperate lakes, maybe the “best” thing to do is to fish somewhere else entirely. I understand why E is the better answer, but could you please explain why C is definitely wrong?

[Luke Haqq]

Hi lyujenny!

To understand why (C) can't be the right answer, consider the language in the last sentence:

So, if anglers seek lake trout in deep temperate lakes while these lakes are partially iced over in late winter, they will do best to eschew the lake trout’s summer haunts and fish instead in a shallow bay or close to the surface off a rocky point.

The italicized part functions as a premise, while the rest is the conclusion. Since that first part functions as a premise that one must take as true, then it's not relevant if there are other "better" places where trout can be found. The conclusion is only a recommendation directed at "anglers [who] seek lake trout in deep temperate lakes while these lakes are partially iced over in late winter."

So, even if (C) were negated in using the Assumption Negation technique, it wouldn't make the argument fall apart, so it couldn't be the correct answer. Hope that helps!

[crispycrispr]

Can someone please explain why (A) is wrong? I got right (E) because of prephrasing, but (A) actually looked attractive to me. If easiness does not vary with water temperature/time of year, it seems like it would make the argument fall apart because it does say that people "will do best to" fish at a particular season and place.

[kupwarriors9]

May I ask how you pre-phrased get E (i.e. your thought process)? Thanks!

Can someone please explain why (A) is wrong? I got right (E) because of prephrasing, but (A) actually looked attractive to me. If easiness does not vary with water temperature/time of year, it seems like it would make the argument fall apart because it does say that people "will do best to" fish at a particular season and place.

[crispycrispr]

May I ask how you pre-phrased get E (i.e. your thought process)? Thanks!

Can someone please explain why (A) is wrong? I got right (E) because of prephrasing, but (A) actually looked attractive to me. If easiness does not vary with water temperature/time of year, it seems like it would make the argument fall apart because it does say that people "will do best to" fish at a particular season and place.

Hi, sure! Basically, when the stimulus talks about "partially iced over," I thought that was kind of vague. We know that the turnover occurs in fall and late winter, but it wasn't clear whether the "partially iced over" late winter is the same late winter where turnover occurs. I'm from a place where in the winter, lakes freeze, so that additional detail really just stuck out to me as being odd and ambiguous. Then, I basically hunted for the answer, then I negated (E) to confirm.

Now I'm thinking (A) is actually not necessary at all because really, how easy it is to catch fish depends on a lot of other things like skill. (A) isn't talking about ease as in top vs. bottom ease, but just in general.

[crispycrispr]

May I ask how you pre-phrased get E (i.e. your thought process)? Thanks!

Can someone please explain why (A) is wrong? I got right (E) because of prephrasing, but (A) actually looked attractive to me. If easiness does not vary with water temperature/time of year, it seems like it would make the argument fall apart because it does say that people "will do best to" fish at a particular season and place.

Cont: The negation of (E), luckily for me, was easy--if turnover already occurred, then that means we're back to the situation where more fish is at the bottom, so then it doesn't make sense at all to look for fish in shallow water, i.e. the top of the lake.

To elaborate, though, I think what helped is that because of the way the stimulus is, I knew I had to understand what it was saying first. Looking back, that's what better helped me prephrase the correct answer choice rather than falling into an attractive wrong answer like (A).

[Rachael Wilkenfeld]

Great work, crisper!

Kup, turning to answer choice (A), if we negate it, we get that the ease of catching trout does not vary with time of year and water temp. We know the location of the trout varies because the location of the coldest water varies based on time of year. But it does not have to be the case the ease varies from time of year and water temp. Maybe it's just as easy to catch the fish in the upper layers v the bottom layers. Maybe there's always a magic sweet spot every time of year. Answer choice (A) is not a required assumption here.

On the other hand, answer choice (E) is required. The turnover cannot have happened yet in order to know that the the shallow parts are the place to be. If the turnover had already occured, you wouldn't check for the fish in the shallow parts of the lake.

Hope that helps!