While the Darwinian evolutionary principle of "survival of the fittest

Question

While the Darwinian evolutionary principle of "survival of the fittest" is frequently associated with physical characteristics such as size, strength, speed, and appearance, the same principle is thought to apply to behavioral traits as well, such as how an animal responds to a perceived threat. Experiments to evaluate the consequences of that behavior are virtually impossible in a laboratory environment. However, a unique set of circumstances and some clever thinking by scientists enabled them to conduct an experiment to quantify the survival rate of animals displaying differing threat responses in a real-world environment.

A series of hurricanes had devastated several small islands in the Bahamas; no lizards at all survived on some of these islands. Scientists determined that this situation presented an opportunity to test the effects of brown anole behavior on these animals' survival. When confronted with a threat, some brown anoles are risk-averse and will retreat to the safety of thick vegetation or find a hole in the ground to hide. Others may stay above ground, thus exposing themselves to a greater likelihood of becoming prey. In order to characterize their risk behavior, the scientists placed a large group of the brown anoles in a cage with a direct view of a large predator. The predator was then relocated, and the team measured how long it took each lizard to venture out of the cage; that time was used as a proxy for risk-taking propensity. The lizards were tagged, and a representative population was dispersed across each of the islands along with a number of curly-tailed lizards, which prey on brown anoles. The scientists hypothesized that the survival rate would be higher among those brown anoles with a tendency to hide when facing danger.

Four months after the repopulation event, all of the surviving brown anole lizards were recaptured. It was found that a greater proportion of the risk-averse brown anoles survived thanof the more adventurous lizards. However, further analysis showed that risk aversion had no predictive value onthe survival rates of male brown anoles; only the risk-averse females had a higher survival rate. Rather than believing their hypothesis had been disproved, the scientists claimed that these results were consistent with what they had predicted. Either way, the experiment demonstrates the value of opportunistic methodology in science.
   1 
 1. Which of the following, if true, would most support the scientists' hypothesis?

(A) The longer a brown anole stayed in the cage in the characterization phase of the experiment, the more likely that anole would be to hide from a predator in the wild.
(B) Some brown anoles have a prominent orange crest that is highly visible to curly-tailed lizards and other predators.
(C) Male brown anoles are less likely to be risk-averse than are female brown anoles.
(D) During breeding season, brown anoles are more vulnerable to predators due to their mating displays.
(E) Female brown anoles will not risk their own lives to protect their eggs or offspring from predators.

2 
 2. According to the passage, which of the following is true about brown anoles?

(A) Brown anoles are native to the Bahamas.
(B) A low level of risk aversion provides no benefit to brown anoles.
(C) Threat response behavior varies among brown anoles.
(D) The brown anole's main threat response strategy is hiding.
(E) The curly-tailed lizard is the primary predator of brown anoles.

3 
 3. It can be inferred from the passage that the author would be likely to agree with which of the following statements about the experiment's results?

(A) The results support the scientists' hypothesis more than they undermine it.
(B) The results of this experiment contradicted those of previous laboratory experiments.
(C) The results would have been more accurate had the scientists used a species native to the islands.
(D) Potentially inconclusive results can still have value in science.
(E) Risk aversion in brown anoles has no effect on their survival.

4 
 4. Based on the passage, which of the following can be inferred about Darwinian principles?

(A) "Survival of the fittest" applies only to physical characteristics.
(B) Threat response behavior may be subject to evolutionary selection.
(C) There is no way to evaluate evolutionary principles in a laboratory setting.
(D) The principle of "survival of the fittest" applies to both physical and behavioral characteristics.
(E) The response of most behavioral traits to evolutionary selection can be experimentally evaluated.

bM22 · Answer

4) Based on the passage, which of the following can be inferred about Darwinian principles?

A) "Survival of the fittest" applies only to physical characteristics.
B) Threat response behavior may be subject to evolutionary selection.
C) There is no way to evaluate evolutionary principles in a laboratory setting.
D) The principle of "survival of the fittest" applies to both physical and behavioral characteristics.
E) The response of most behavioral traits to evolutionary selection can be experimentally evaluated.

Correct Answer : B,
Explanation: We can infer from the passage, that experiments performed for proving that "survival of the fittest", which is thought to apply to behavioral traits as well, were inconclusive. So we cannot infer D. The scientists found that: "It was found that a greater proportion of the risk-averse brown anoles survived thanof the more adventurous lizards. However,  further analysis showed that risk aversion had no predictive value onthe survival rates of male brown anoles ; only the risk-averse females had a higher survival rate.", implying that the survival was not really dependent on behavioral traits, instead it was a result of how the animals had evolved and grown to the surroundings (Evolutionary Selection).

Thanks.

bM22 · Answer

3) It can be inferred from the passage that the author would be likely to agree with which of the following statements about the experiment's results?

A) The results support the scientists' hypothesis more than they undermine it.
B) The results of this experiment contradicted those of previous laboratory experiments.
C) The results would have been more accurate had the scientists used a species native to the islands.
D) Potentially inconclusive results can still have value in science.
E) Risk aversion in brown anoles has no effect on their survival.

Correct Answer: D,
Explanation: as mentioned in the passage: " Rather than believing their hypothesis had been disproved, the scientists claimed that these results  were consistent with what they had predicted. Either way, the experiment demonstrates the value of opportunistic methodology in science.", implying that even though the results were inconclusive, they were still consistent with the scientists' hypothesis.
Option A is incorrect as the scientists did not undermine or underestimate the results, instead, they claimed that it was consisted with their predictions.

Thanks.

GDT · Answer

thanks for the response!

can you pls explain what exactly was scientists' hypothesis?

bM22 · Answer

Hi  GDT ,

What scientists were trying to achieve : "survival of the fittest" applies to behavioral traits as well such as how an animal responds to a perceived threat, as mentioned in the lines: "a unique set of circumstances and some clever thinking by scientists enabled them to conduct an experiment to quantify the survival rate of animals displaying differing threat responses in a real-world environment."

The results that they got: It was found that a greater proportion of the risk-averse brown anoles survived thanof the more adventurous lizards. However, further analysis showed that risk aversion had no predictive value onthe survival rates of male brown anoles; only the risk-averse females had a higher survival rate,
implying that the survival rate was not solely dependent on the behaviourial traits. It was more of how the species had come to grow in that environment.

Hope this Helps.
Thanks.

sarphant123 · Answer

Kaplan's Explanation

1. Which of the following, if true, would most support the scientists' hypothesis?

(A) The longer a brown anole stayed in the cage in the characterization phase of the experiment, the more likely that anole would be to hide from a predator in the wild.
(B) Some brown anoles have a prominent orange crest that is highly visible to curly-tailed lizards and other predators. 
(C) Male brown anoles are less likely to be risk-averse than are female brown anoles. 
(D) During breeding season, brown anoles are more vulnerable to predators due to their mating displays. 
(E) Female brown anoles will not risk their own lives to protect their eggs or offspring from predators.

Analyze the question stem This is a Strengthen question that asks for evidence to support the scientists' claim that their hypothesis is correct.

Research the relevant text

The hypothesis is given at the end of the second paragraph; the scientists thought that risk-averse brown anoles would have a higher survival rate than risk-prone anoles. First risk aversion was determined, and then survival rate was measured. Risk-averse anoles were defined as those that hide when encountering predators; for the experiment, this was measured by determining how long it took for a brown anole to leave its cage after viewing a predator. The third paragraph discusses the results; the experiment showed that risk aversion did correlate with survival rate for females, not for males.

Make a prediction One weakness in the scientists' findings is that risk-averse behavior helped only the females, so the correct answer might explain why risk-averse behavior doesn't help the males. That is, evidence that shows that hiding would help the males if not for some other, sex-related factor would support the hypothesis that risk-averse behavior promotes survival.

Alternatively, since the experiment measured risk aversion in a way that is different from how it is defined in the hypothesis (by letting the lizards view predators from the safety of cages instead of making them escape predators in the wild), it may also explain how those two measures are equivalent.

Evaluate the answer choices  
(A) is correct; it indicates that the measurement of risk aversion the scientists used does in fact correlate with risk aversion in the wild. 
(B) may be tempting because it provides a reason that risk aversion doesn't help some brown anoles survive: they can't hide their crest. However, this choice does not specify that it's the males that have this crest, so it doesn't support the scientists' hypothesis. 
(C) might seem like it provides a reason that male and female brown anoles have different survival rates. The hypothesis, though, does not depend on how likely brown anoles are to be risk-averse; it focuses on whether those that are risk-averse have a higher survival rate.
(D) is incorrect because it does nothing to connect risk aversion to survival rate. 
(E) explains another way in which female brown anoles avoid risks and perhaps indicates that more females than males would be characterized as risk averse. However, it does nothing to explain why risk-averse females have a higher survival rate than risk-averse males.

TAKEAWAY: There may be more than one way to strengthen a claim. Before evaluating the answer choices, consider the different links in the argument's chain of reasoning and think about what evidence would strengthen each.

2. According to the passage, which of the following is true about brown anoles?

A) Brown anoles are native to the Bahamas.
B) A low level of risk aversion provides no benefit to brown anoles.
C) Threat response behavior varies among brown anoles.
D) The brown anole's main threat response strategy is hiding.
E) The curly-tailed lizard is the primary predator of brown anoles.

Analyze the question stem

This asks for something the passage tells you about brown anoles, so it's a Detail question.

Research the relevant text Paragraphs 2 and 3 both talk about brown anoles, so researching both of them would likely not be an efficient use of time. Instead, be ready to research each choice as needed.

Make a prediction Similarly, a specific prediction isn't possible since the passage provides a number of facts about the brown anole. Instead, keep in mind the scope and purpose(to explain an experiment testing the effect of risk aversion on survival rates) as you evaluate each choice.

Evaluate the answer choices

(C) is correct. Risk aversion is described as a threat response strategy, and paragraph 2 describes two levels of risk aversion among brown anoles. 
(A) is incorrect because the passage doesn't state whether brown anoles are native to the Bahamas; rather, it only states that the Bahamas were used as a setting for this experiment. The passage states that a high level of risk aversion is correlated with a higher survival rate. However, that doesn't mean that a low level of risk aversion has no benefit at all; it may help in other ways.
Eliminate (B).
(D) is too extreme; hiding is one strategy used by brown anoles to avoid predators, but it's possible they use other strategies. 
(E) is similarly too extreme. While the curly-tailed lizard was deployed as the predator in this experiment, it may be that the brown anole has other predators in a more typical habitat that hasn't been swept by a hurricane. TAKEAWAY: Extreme answers are common in Inference questions, but they can also show up in Detail questions. Don't pick an extreme answer unless the information in the passage supports that level of certainty.

3. It can be inferred from the passage that the author would be likely to agree with which of the following statements about the experiment's results?

A) The results support the scientists' hypothesis more than they undermine it.
B) The results of this experiment contradicted those of previous laboratory experiments.
C) The results would have been more accurate had the scientists used a species native to the islands.
D) Potentially inconclusive results can still have value in science.
E) Risk aversion in brown anoles has no effect on their survival.

Analyze the question stem

This asks for something the author would be likely to agree with, and it points you in a specific direction; the correct answer will describe the author's opinions of the experiment's results.

Research the relevant text The results of this experiment are described in the third paragraph. In the last sentence of this paragraph, the author injects his opinion, returning to the theme introduced in the first paragraph of the scientists' "clever thinking" by praising the "opportunistic methodology" of their experiment. The scientists think the results support their hypothesis, but the words "either way" at the beginning of the last sentence indicate that the author is withholding judgment on this matter.

Make a prediction Look for an answer that conveys the idea that whether or not the results were conclusive, the experiment was worth conducting.

Evaluate the answer choices

(D) matches the prediction; the results may be inconclusive, but they have value.
(A) and (E) are both wrong for the same reason; they impute too certain an opinion to the author. The author isn't sure that the results support the scientists' hypothesis, but he's also not sure that the experiment showed that risk aversion has no effect on survival. 
(B) is incorrect because these results aren't compared to those of other experiments; furthermore, according to the first paragraph, it would be virtually impossible to run this experiment into a laboratory. 
(C) is wrong because the author never opines on whether there was a better way for this experiment to be run. Indeed, the author is complimentary about the experiment.

TAKEAWAY: When the correct answer must reflect the author's opinion, avoid choices that reflect someone else's opinion. Researching what the author thinks and holding that prediction firmly in mind will help you eliminate incorrect choices.

4 Based on the passage, which of the following can be inferred about Darwinian principles?

A) "Survival of the fittest" applies only to physical characteristics.
B) Threat response behavior may be subject to evolutionary selection.
C) There is no way to evaluate evolutionary principles in a laboratory setting.
D) The principle of "survival of the fittest" applies to both physical and behavioral characteristics.
E) The response of most behavioral traits to evolutionary selection can be experimentally evaluated.

Analyze the question stem

This asks for something that can be inferred, so it's an Inference question.

Research the relevant text The correct answer will be a fully supported statement about Darwinian principles, which are explicitly mentioned in the first paragraph. Make a prediction The first paragraph says that while Darwinian principles were thought to apply only to physical characteristics, they're thought to apply to behavior as well. Furthermore, while it's hard to test behavioral evolution, some scientists have designed an experiment to test one aspect of behavior.

Look for a choice that makes one of these points.

Evaluate the answer choices

(B) is correct; it states that Darwinian principles may affect behavioral traits. Note that this is correct because of the word "may"; anything more certain wouldn't be supported. (A) distorts information from the passage. The author doesn't say that Darwinian principles don't apply to non-physical traits; the author just says that this idea can be hard to test.
(C) also distorts the passage. There's no indication that it's difficult to test all evolutionary principles. While it's "virtually impossible" to test the relationship between evolutionary principles and behavior in a laboratory, it may be easier to test other areas of evolution. 
(D) is extreme. Only one behavioral trait was tested, so this broad statement that evolutionary principles apply to behavioral characteristics in general is unsupported. 
(E) is wrong for similar reasons; the passage shows only how one specific behavior can be evaluated in an experiment. This may not be possible for other behaviors.

TAKEAWAY: For Inference questions, beware of answer choices that are too broad. The correct choice will reflect what the passage says and not go beyond that.

siddhantmittal · Answer

1) Which of the following, if true, would most support the scientists' hypothesis?

Pre-thought: what is the hypothesis? "The scientists hypothesized that the survival rate would be higher among those brown anoles with a tendency to hide when facing danger."

A) The longer a brown anole stayed in the cage in the characterization phase of the experiment, the more likely that anole would be to hide from a predator in the wild.  Correct- supports the hypothesis 
B) Some brown anoles have a prominent orange crest that is highly visible to curly-tailed lizards and other predators. Incorrect- doesn't support the scientist 
C) Male brown anoles are less likely to be risk-averse than are female brown anoles. Incorrect- the hypothesis doesn't differentiate between female and male anoles
D) During breeding season, brown anoles are more vulnerable to predators due to their mating displays. Incorrect- doesn't support the hypothesis
E) Female brown anoles will not risk their own lives to protect their eggs or offspring from predators. Incorrect

2) According to the passage, which of the following is true about brown anoles?

A) Brown anoles are native to the Bahamas. Incorrect
B) A low level of risk aversion provides no benefit to brown anoles. Incorrect
C) Threat response behavior varies among brown anoles. Correct - "When confronted with a threat, some brown anoles are risk-averse and will retreat to the safety of thick vegetation or find a hole in the ground to hide. Others may stay above ground, "
D) The brown anole's main threat response strategy is hiding. Incorrect- we don't know whether hiding is the main strategy
E) The curly-tailed lizard is the primary predator of brown anoles. Incorrect- we don't know if lizard is the primary predator

3) It can be inferred from the passage that the author would be likely to agree with which of the following statements about the experiment's results?

Pre-thought: look at the conclusion presented by the scientists in the third paragraph. "Either way, the experiment demonstrates the value of opportunistic methodology in science." It means irrespective of whatever the result was, it was beneficial to conduct the experiment

A) The results support the scientists' hypothesis more than they undermine it.
B) The results of this experiment contradicted those of previous laboratory experiments.
C) The results would have been more accurate had the scientists used a species native to the islands.
D) Potentially inconclusive results can still have value in science. Correct- bang on!
E) Risk aversion in brown anoles has no effect on their survival

4) Based on the passage, which of the following can be inferred about Darwinian principles?

Still not very convinced with the OA..

A) "Survival of the fittest" applies only to physical characteristics. Incorrect- "While the Darwinian evolutionary principle of "survival of the fittest" is frequently associated with physical characteristics such as size, strength, speed, and appearance, the same principle is thought to apply to behavioral traits as well,"
B) Threat response behavior may be subject to evolutionary selection.
C) There is no way to evaluate evolutionary principles in a laboratory setting.
D) The principle of "survival of the fittest" applies to both physical and behavioral characteristics. Seems like the correct answer as per the passage
E) The response of most behavioral traits to evolutionary selection can be experimentally evaluated

shloka30 · Answer

Hey , for question 3 - How have we concluded that the results are inconclusive, it is had been concluded that risk aversion only helps femails anoles. 
For question 4 - how do we reject Option D?

guddo · Answer

3. It can be inferred from the passage that the author would be likely to agree with which of the following statements about the experiment's results?

The passage says the experiment partly supported the scientists’ hypothesis: risk-averse brown anoles survived at a higher rate overall. But the result was not clean because risk aversion predicted survival only among females, not males.  The author’s final point  is that even if the results are not fully conclusive, the experiment still shows the value of  opportunistic methodology  in science.

A) The results support the scientists' hypothesis more than they undermine it.

This is tempting, but too strong. The passage says the scientists claimed the results were consistent with their prediction, but the author does not clearly say the results support the hypothesis more than they undermine it.

B) The results of this experiment contradicted those of previous laboratory experiments.

This is unsupported. The passage says such experiments are virtually impossible in a laboratory environment.

C) The results would have been more accurate had the scientists used a species native to the islands.

This is unsupported. The passage gives no reason to think the species choice reduced accuracy.

D) Potentially inconclusive results can still have value in science.

This is correct. The results were mixed because risk aversion mattered for females but not males. Still, the author says the experiment demonstrates the value of opportunistic methodology.

E) Risk aversion in brown anoles has no effect on their survival.

This is incorrect. Risk aversion did have predictive value for female brown anoles, and risk-averse anoles survived at a higher rate overall.

Answer: (D)

guddo · Answer

4. Based on the passage, which of the following can be inferred about Darwinian principles?

The passage says “survival of the fittest” is often associated with physical traits, but the same principle is thought to apply to behavioral traits as well, including how an animal responds to danger.  So the safest inference is that threat-response behavior may be shaped by evolutionary selection .

A) "Survival of the fittest" applies only to physical characteristics.

This is incorrect. The passage explicitly says the principle is thought to apply to behavioral traits as well.

B) Threat response behavior may be subject to evolutionary selection.

This is correct. The passage specifically uses threat response in brown anoles as an example of a behavioral trait whose survival consequences can be studied.

C) There is no way to evaluate evolutionary principles in a laboratory setting.

This is too broad. The passage says experiments on this particular behavior are virtually impossible in a laboratory, not that evolutionary principles generally cannot be tested there.

D) The principle of "survival of the fittest" applies to both physical and behavioral characteristics.

This is close, but slightly stronger than the passage. The passage says the principle is  thought to apply  to behavioral traits; B states the inference more cautiously.

E) The response of most behavioral traits to evolutionary selection can be experimentally evaluated.

This is unsupported. The passage discusses one type of behavior in one experiment, not most behavioral traits.

Answer: (B)

egmat · Answer

Hi shloka30,

These two doubts actually share one root: how strong a claim the passage will let you make. Let me take them one at a time.

Q3 - why "inconclusive"?

Look closely at what the scientists  predicted  versus what they  found :

-  Hypothesis:  risk-averse brown anoles (the ones that hide) would have a higher survival rate. This was a claim about brown anoles in general - it did not single out one sex.
-  Result:  risk aversion helped survival  only in females ; for males it "had no predictive value."

So the data neither cleanly confirms the hypothesis (it failed for half the population) nor cleanly disproves it (it worked for the other half). That split is exactly what makes the outcome  ambiguous  - the scientists call it consistent with their prediction, but the author refuses to take a side. Notice the author's words:  "Either way, the experiment demonstrates the value of opportunistic methodology in science."  "Either way" tells you the author is staying neutral on whether the hypothesis held - which is why  D  (inconclusive results can still have value) fits, and why a confident A is wrong.

So the female-only finding isn't a  clean  success; it's precisely the half-and-half result that earns the word "inconclusive."

Q4 - why reject D?

This comes down to one phrase in the first sentence. The passage says the principle  "is  thought to apply  to behavioral traits as well."  That is a tentative, reported view - not an established fact.

-  D  says survival of the fittest  "applies to both physical and behavioral characteristics"  - stated as settled truth. The passage never asserts that; it only says it's  thought to  apply, and the experiment that tested it gave a mixed result. Too strong.
-  B  says threat-response behavior  " may  be subject to evolutionary selection."  That "may" matches the passage's own hedging exactly.

A quick gut-check on the "thought to / is" gap:  "Blue is  thought to  improve focus."  You can safely infer that people  regard  blue that way - not that blue  does  improve focus. Read the passage line the same way, and D's certainty falls apart while B's "may" survives.

Answer: D; B

egmat · Answer

Hi shloka30,

These two doubts actually share one root: how strong a claim the passage will let you make. Let me take them one at a time.

Q3 - why "inconclusive"?

Look closely at what the scientists  predicted  versus what they  found :

-  Hypothesis:  risk-averse brown anoles (the ones that hide) would have a higher survival rate. This was a claim about brown anoles in general - it did not single out one sex.
-  Result:  risk aversion helped survival  only in females ; for males it "had no predictive value."

So the data neither cleanly confirms the hypothesis (it failed for half the population) nor cleanly disproves it (it worked for the other half). That split is exactly what makes the outcome  ambiguous  - the scientists call it consistent with their prediction, but the author refuses to take a side. Notice the author's words:  "Either way, the experiment demonstrates the value of opportunistic methodology in science."  "Either way" tells you the author is staying neutral on whether the hypothesis held - which is why  D  (inconclusive results can still have value) fits, and why a confident A is wrong.

So the female-only finding isn't a  clean  success; it's precisely the half-and-half result that earns the word "inconclusive."

Q4 - why reject D?

This comes down to one phrase in the first sentence. The passage says the principle  "is  thought to apply  to behavioral traits as well."  That is a tentative, reported view - not an established fact.

-  D  says survival of the fittest  "applies to both physical and behavioral characteristics"  - stated as settled truth. The passage never asserts that; it only says it's  thought to  apply, and the experiment that tested it gave a mixed result. Too strong.
-  B  says threat-response behavior  " may  be subject to evolutionary selection."  That "may" matches the passage's own hedging exactly.

A quick gut-check on the "thought to / is" gap:  "Blue is  thought to  improve focus."  You can safely infer that people  regard  blue that way - not that blue  does  improve focus. Read the passage line the same way, and D's certainty falls apart while B's "may" survives.

Answer: D; B

While the Darwinian evolutionary principle of "survival of the fittest

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While the Darwinian evolutionary principle of "survival of the fittest

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