#20 - Amphibian populations are declining in numbers

[elbism]

elbism,

The information and logic you came up with regarding evolution is interesting, and I'm not qualified to judge it, but I can judge its validity on the test! It's extraneous information that you can't assume - while it may be true in reality, the testmakers don't assume its truth or falsity because it's information brought in from the outside.

Thus, you can't assume that if a species declines, its habitat will also decline. It's simply outside information, a worthy topic for a science class but not something you should use on the LSAT itself.

So, while the natural habitat may or may not be affected by ozone, these amphibians' decline is something the stimulus provides one explanation for - depleted ozone layer - but for which there are multiple alternative explanations. One of those is that the habitat is becoming smaller. As you pointed out, and this IS ok to consider, the habitat may decline because of the depleting ozone layer. On the other hand, it may decline for unrelated reasons. The point is that the habitat's becoming smaller may be a cause unrelated to the ozone layer, which would independently account for the amphibians' decline. Whether or not we can tell that it is independent, its very possibility makes it tough to say whether the author of the stimulus is right that the depleted ozone layer is the primary cause of the amphibians' decline. Because of that uncertainty, we'd feel a lot better about the conclusion if we could just get rid of the alternative explanation entirely - and that's what answer choice (D) does.

Robert Carroll

Another thing - if this is outside information that we can't bring in, that should also include the real reason this answer is incorrect which is, as stated in the powerscore book, that it hasn't been destroyed by humans or some other source. Is that not outside information that we are supposed to have attached to this idea that it 'hasn't gotten smaller'? Because the human desecration was not my knee-jerk response, it was the natural decline concept. My question is, I suppose, does the concept of 'outside information' not pertain to relativity?

So the statement is "the natural habitats have not become smaller"
- the fact that this means it hasn't been reduced by humans, is outside information we can assume
but the fact that this means it hasn't been reduced naturally is outside information we can not assume?

The lines are extremely blurred for me still.

Also, we're assuming the answer choices to be true (2nd family)
so if we are to assume indeed that "the natural habitats have not become smaller", that still 'definitely' rules out the 'maybe' possibility of the functioning darwin theory, meaning that if the habitats have not become smaller then there is room to believe that amphibians have not declined at all and that completely disproves the stimulus. Irrespective of the background of how or why it's true, the fact that it's true that it has not become smaller (we are told to assume as true) should suffice to encompass the natural possibility among all it's possibilities of why, and thus completely discount that theory (the theory that could weaken it).

[Adam Tyson]

A lot going on here and I'm coming in at the end, but I'll come in with this - there's nothing "maybe" about answer D unless you bring in outside analysis to help it become something more than what it is. It eliminates a possible alternate cause, so it strengthens - no room for doubt there. An answer that said "magical fairies did not curse the amphibians so that they could no longer reproduce" would strengthen the argument for the same reason. It doesn't have to strengthen much, but if it eliminates any alternate cause, it strengthens the casual claim. Spending any time on trying to argue for one answer or against another may hone a skill you'll need in law school and in the practice of law, but it can only get in the way here. Leave outside information where it belongs - outside!

Fascinating stuff here - I love it! Just getting back to the task at hand - LSAT prep - I hope we can all agree on the results here.

[elbism]

A lot going on here and I'm coming in at the end, but I'll come in with this - there's nothing "maybe" about answer D unless you bring in outside analysis to help it become something more than what it is. It eliminates a possible alternate cause, so it strengthens - no room for doubt there. An answer that said "magical fairies did not curse the amphibians so that they could no longer reproduce" would strengthen the argument for the same reason. It doesn't have to strengthen much, but if it eliminates any alternate cause, it strengthens the casual claim. Spending any time on trying to argue for one answer or against another may home a skill you'll need in law school and in the practice of law, but it can only get in the way here. Leave outside information where it belongs - outside!

Fascinating stuff here - I love it! Just getting back to the task at hand - LSAT prep - I hope we can all agree on the results here.

It eliminates an alternate cause only if it means something along the suggestions you mentioned. I.e. Destroyed by humans or magical fairies, which, as you correctly stated is irrelevant. But if it declined because of amphibian decline via the ozone layer scenario then it becomes very relevant and actually weakens the argument. I feel like the explanations given are reliant on the presumption that "it has not gotten smaller" must mean one thing and one thing clearly, when it is actually very ambiguous as to what that could actually mean and the test makers were not specific enough I think

[elbism]

The point I'm trying to make is, "the natural habitat hasn't gotten smaller" relies on outside information which, as correctly stated, is irrelevant, but equally has the potential to strengthen (prove there is no alternate cause) or weaken (prove this is indeed the cause) both of which we are not justifiably in a position to assess since it relies on the very information that we are not privy too, NOR are we supposed to be privy too. Therefore, we can not justifiably assess whether or not this is an incorrect or correct answer choice, and since we can not justifiably assess this, i don't believe it has sufficient grounds to fairly be deemed as an incorrect answer choice. I believe a fair incorrect answer choice would be "the habitat has not gotten smaller due to human desecration."

This might seem like an overdrawn out point, however I think it's a strong area of contention and if I can't agree on this question here, there's a chance i'll feel the same way about a question on the LSAT which i'll ultimately end up losing a point on... and I definitely don't want to do that!

[Clay Cooper]

Hi elbism,

If I might weigh (wade...lolol...amphibian habitat) in, I think the last paragraph of your last post is particularly astute. I would just point out a couple of its implications to you. Yes, it's possible that there will be a question on your LSAT with which you don't agree, and it could conceivably even cost you a point (though, mathematically, even if such a question does occur, it is unlikely to cost you a point). Sometimes in class my students will pick a particular hill to die on, if you'll forgive the metaphor, and I've come to think of it this way:

Let's say, hypothetically, you're right, and justified in disliking the question. I think it is safe to say you are powerless to eliminate the possibility of a similarly ambiguous-to-you question from appearing on the LSAT you take. Ok, so what are your options?
1. Wage a letter-writing campaign to LSAC in the hopes of getting that question discounted. It might work. It will probably take a while. It is unlikely to make the difference in getting into the law school you want to go to.
2. Spend the time, energy, and passion you have shown in defending your viewpoint on further preparing for the LSAT.

I think option two is far superior; in my experience any time you devote toward trying to convince the test-makers (or moderators, or anyone) that a question is amphibious *cough* ambiguous is time wasted. Even if you are right, you can't prevent the (highly unlikely) scenario from repeating on your test, and, more importantly, there are far more productive ways to spend your time in preparing.

I appreciate your tenacity. You will probably be a good attorney.

[elbism]

Hi elbism,

If I might weigh (wade...lolol...amphibian habitat) in, I think the last paragraph of your last post is particularly astute. I would just point out a couple of its implications to you. Yes, it's possible that there will be a question on your LSAT with which you don't agree, and it could conceivably even cost you a point (though, mathematically, even if such a question does occur, it is unlikely to cost you a point). Sometimes in class my students will pick a particular hill to die on, if you'll forgive the metaphor, and I've come to think of it this way:

Let's say, hypothetically, you're right, and justified in disliking the question. I think it is safe to say you are powerless to eliminate the possibility of a similarly ambiguous-to-you question from appearing on the LSAT you take. Ok, so what are your options?
1. Wage a letter-writing campaign to LSAC in the hopes of getting that question discounted. It might work. It will probably take a while. It is unlikely to make the difference in getting into the law school you want to go to.
2. Spend the time, energy, and passion you have shown in defending your viewpoint on further preparing for the LSAT.

I think option two is far superior; in my experience any time you devote toward trying to convince the test-makers (or moderators, or anyone) that a question is amphibious *cough* ambiguous is time wasted. Even if you are right, you can't prevent the (highly unlikely) scenario from repeating on your test, and, more importantly, there are far more productive ways to spend your time in preparing.

I appreciate your tenacity. You will probably be a good attorney.

Lol. Great answer. It made me chuckle. I suppose I'll have to wait till law school to find my hills to die on.

[harvoolio]

I had selected (E).

I also think I misread answer (A), but this distinction might not matter. If read answer (A) more like "Of the various types of radiation produced by the sun, UV-B is the only type that can damage genes." If that had been (A) would that have strengthened the argument by eliminating alternate causes of radiation from the sun not blocked by ozone, hence strengthening the argument that ozone depletion is the primary cause of the declining amphibian population?

Also, I chose (E) as not strengthening figuring continuous decline shows potentially another cause in that if ozone depletion were the issue you have a higher rate of population decline in more recent years, because there is less ozone (from the continuous ozone depletion over the last 50 years) to block the UV-B. In other words, with continuous ozone depletion you have increasing amounts of UV-B which would increasingly kill amphibians.

Thanks.

[Alex Bodaken]

harvoolio,

Interesting question. Hypotheticals are hard, but I think that what you write in your alternative to answer (A) would strengthen for the reason you note...it would eliminate that other radiation not blocked by the ozone could cause damage.

As for answer (E), it's a bit tricky - it says the amphibian population has declined continuously for the last 50 years...it does not say *at the same rate.* So it's possible that the rate at which the population is declining has, in fact, picked up as more of the ozone has gone away. And crucially, answer choice (E) rules out the possibility that, for example, the decline has been sporadic or that there have been periods of uptick in the population - which more closely links the population decline to the (continuous) ozone decline.

Hope that helps!
Alex

[harvoolio]

Excellent point. Thanks.

[lsacgals101]

Hi Curiosity!

So with this question you really need to focus on the conclusion and the specific wording of it. The conclusion in the stimulus is the last sentence, after the conclusion indicator word "thus." It's a causal conclusion with "depletion of the ozone layer" given as the cause and "declining amphibian population" given as the effect.

Let's start with how answer choice (E) strengthens the argument. Answer choice (E) tells us that the amphibian population has declined continuously over the past 50 years. Since we know from the stimulus that the earth's ozone layer has been continuously depleted over the past 50 years, this answer choice shows that when we have the cause ("depletion of the ozone layer"), we have the effect ("declining amphibian population"). That is one of the 5 ways to strengthen a causal argument so it strengthens the conclusion we have in the stimulus.

Answer choice (A), however, has no effect on the argument. Again, it comes back to focusing on the conclusion. The conclusion is that the "depletion of the ozone layer," not UV-B specifically, is causing the "decline of the amphibian population." It is definitely a little confusing since most of the premises talk about UV-B specifically. That's why it's always important to focus on the precise wording of the conclusion. We're not trying to show that UV-B is causing the drop in the amphibian population, so we don't need to eliminate alternate causes to UV-B. Answer choice (A) just tells us that UV-B is the only type of radiation blocked by the atmospheric ozone that can damage genes but this doesn't strengthen our argument that "depletion of the ozone layer" is causing the "decline of the amphibian population."

Since we are looking for something which does not strengthen the argument, answer choice (A) is our correct answer.

Hope this helps!

Best,
Kelsey

Hi Kelsey,

I am somewhat following your logic about answer E but am hung up on the fact that E would not strengthen the argument because it is merely showing that the two events occurred simultaneously. The PS bible mentions that one often made error of causality involves assuming that because two things occurred simultaneously, one must have caused the other. So given this information, I am wondering how one could argue that answer E strengthens the argument.