idkksh wrote:
Declines in amphibian populations There are recent reports of apparently drastic declines in amphibian populations and of extinctions of a number of the world's endangered amphibian species. These declines, if real, may be signs of a general trend toward extinction, and many environmentalists have claimed that immediate environmental action is necessary to remedy this "amphibian crisis", which, in their view, is an indicator of general and catastrophic environmental degradation due to human activity.
To evaluate these claims, it is useful to make a preliminary distinction that is far too often ignored. A declining population should not be confused with an endangered one. An endangered population is always rare, almost always small, and, by definition, under constant threat of extinction even without a proximate cause in human activities. Its disappearance, however unfortunate, should come as no great surprise. Moreover, chance events—which may indicate nothing about the direction of trends in population size—may lead to its extinction. The probability of extinction due to such random factors depends on the population size and is independent of the prevailing direction of change in that size.
For biologists, population declines are potentially more worrisome than extinctions. Persistent declines, especially in large populations, indicate a changed ecological context. Even here, distinctions must again be made among declines that are only apparent (in the sense that they are part of habitual cycles or of normal fluctuations), declines that take a population to some lower but still acceptable level, and those that threaten extinction (e.g., by taking the number of individuals below the minimum viable population). Anecdotal reports of population decreases cannot distinguish among these possibilities, and some amphibian populations have shown strong fluctuations in the past.
It is Indisputably true that there is simply not enough long-term scientific data on amphibian populations to enable researches to identify real declines in amphibian populations. Many fairly common amphibian species declared all but extinct after severe declines in the 1950s and 1960s have subsequently recovered, and so might the apparently declining populations that have generated the current appearance of an amphibian crisis. Unfortunately, long-term data will not soon be forthcoming, and postponing environmental action while we wait for it may doom species and whole ecosystems to extinction.
6. Which of the following best describes the function of the sentence in lines 35-38 [
Anecdotal reports of population decreases cannot distinguish among these possibilities, and some amphibian populations have shown strong fluctuations in the past.]?
(A) To give an example of a particular kind of study
(B) To cast doubt on an assertion made in the previous sentence
(C) To raise an objection to a view presented in the first paragraph
(D) To provide support for a view presented in the first paragraph
(E) To introduce an idea that will be countered in the following paragraph
Passage: Amphibian Populations
Question: Purpose
The Simple StoryAccording to reports, certain amphibian populations are undergoing drastic decline or even extinction. Environmentalists believe that these changes are due to human activity. The passage explains how to evaluate these claims. First, it draws a distinction between a declining population and an endangered population. Then, it explains that a decline may be worse than an extinction, but may also be harmless. Finally, it concludes that there is not enough data to determine whether the amphibian population is actually declining, and whether that decline represents a crisis. However, since there is limited data, and inaction could cause serious problems, the passage argues that people should still act to protect the amphibians.
Sample Passage Map
Here is one way to map this passage. (Note: abbreviate as desired!)
P1:
- Amph declines & extinctions: bad sign?
- Env.: action needed, declines caused by humans
P2:
- Evaluate env. Claims
- Decline doesn’t = endangered
P3:
- Declines worse than extinctions
- But, some declines are okay
P4:
- Limited data
- Don’t know if amphibians are really declining?
- But: should take action now anyways
Step 1: Identify the QuestionThe phrase function of the sentence in the question stem indicates that this is a Purpose question.
Step 2: Find the SupportReread the sentence mentioned in the question stem and enough of the surrounding passage to provide context.
“Distinctions must again be made among declines that are only apparent…declines that take a population to some lower but still acceptable level, and those that threaten extinction.
Anecdotal reports of population decreases cannot distinguish among these possibilities, and some amphibian populations have shown strong fluctuations in the past.”
The bolded sentence above is the sentence that the question stem refers to.
Step 3: Predict an AnswerThe sentence describes being unable to
distinguish among possibilities. The possibilities mentioned are the various possible scenarios in which a population declines. The author describes these multiple scenarios in order to express that the environmentalists’ worst-case scenario might or might not be correct: the population decline could be dangerous, but it could also be a random fluctuation. The function of this sentence is to summarize one possible reason that the environmentalists’ belief is too pessimistic.
Step 4: Eliminate and Find a Match(A) The sentence addresses anecdotal reports, not studies.
(B) The previous sentence serves the same purpose as the sentence referenced in the question: to note that there are multiple possible scenarios under which a population could decline.
(C) CORRECT. This sentence raises an objection to the environmentalists’ view. The environmentalists believe that there is only one possible scenario in the case of the amphibians, that of a dangerous decline caused by human activity. The sentence claims that there are multiple different possible situations, only some of which are dangerous.
(D) In this sentence, the author disagrees with the environmentalists’ view by asserting that their analysis is not the only possible one.
(E) The following paragraph agrees with the sentiment of this sentence, which is that there is not enough data available to fully analyze the causes and extent of population declines.
Struggling between choices C and E on this question. Looking for a clear explanation.
- Lines 35-38 argues that anecdotal reports of declines are unreliable, and not necessarily an indicator of nearing extinction.
- I initially chose C, but then I read back in the first paragraph and they say "if real", which to me seems to acknowledge the lack of reliability of the anecdotal reports and makes an argument of "if they are true, then this is how we should respond". This lack of clarity led me to shelf answer choice C.
- I ended up choosing E because, while I can see that the first part of the concluding paragraph agrees that the data isn't enough, he introduces an idea which is counter to the notion of the data being insufficient to act on --the author seems to infer that anecdotal reports and limited data are all we have to go off of and we have no choice but to act.
close
17 Nov 2018, 06:15
) The first paragraph says the environmentalists are calling it this an "amphibian crisis," which sounds pretty dramatic and premature. To me, it sounds like these environmentalists are a bit excited and overreacting to the reports that populations are declining. They want to get involved and have "immediate environmental action." Let's hold this one.
