Natural Science Passages

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GMAT Verbal › Natural Science Passages

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1

Adapted from Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by James Richard Ainsworth Davis (1903)

The examples of protective resemblance so far quoted are mostly permanent adaptations to one particular sort of surrounding. There are, however, numerous animals which possess the power of adjusting their color more or less rapidly so as to harmonize with a changing environment.

Some of the best known of these cases are found among those mammals and birds that inhabit countries more or less covered with snow during a part of the year. A good instance is afforded by the Irish or variable hare, which is chiefly found in Ireland and Scotland. In summer, this looks very much like an ordinary hare, though rather grayer in tint and smaller in size, but in winter it becomes white with the exception of the black tips to the ears. Investigations that have been made on the closely allied American hare seem to show that the phenomenon is due to the growth of new hairs of white hue.

The common stoat is subject to similar color change in the northern parts of its range. In summer it is of a bright reddish brown color with the exception of the under parts, which are yellowish white, and the end of the tail, which is black. But in winter, the entire coat, save only the tip of the tail, becomes white, and in that condition the animal is known as an ermine. A similar example is afforded by the weasel. The seasonal change in the vegetarian Irish hare is purely of protective character, but in such an actively carnivorous creature as a stoat or weasel, it is aggressive as well, rendering the animal inconspicuous to its prey.

A stoat might also be called __________.

an ermine, depending on its fur color

a weasel, depending on where it lives

a weasel, depending on its fur color

an ermine, depending on where it lives

a weasel, depending on what it eats

Explanation

The passage’s last paragraph provides the information we need to answer this question. The paragraph begins by describing “the common stoat.” Eventually, it says, “But in winter, the entire coat, save only the tip of the tail, becomes white, and in that condition the animal is known as an ermine.” While this sentence is followed by “A similar example is afforded by the weasel,” this means that the weasel is another example of an animal that changes its fur color, not that a stoat can be called a weasel. It means that a weasel is a distinct type of animal. The correct answer is that a stoat might also be called “an ermine, depending on its fur color.”

2

Adapted from “Birds in Retreat” in “Animal Defences—Active Defence” in Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by James Richard Ainsworth Davis (1903)

Among the large running birds are forms, like the African ostrich, in which the absence of powers of flight is largely compensated by the specialization of the legs for the purpose of rapid movement on the ground. For straightforward retreat in open country nothing could be more effective; but another kind of adaptation is required in birds like rails, which are deficient in powers of flight, and yet are able to run through thickly-growing vegetation with such rapidity as to commonly elude their enemies. This is rendered possible by the shape of their bodies, which are relatively narrow and flattened from side to side, so as to easily slip between the stems of grasses, rushes, and similar plants. Anyone who has pursued our native land-rail or corn-crake with intent to capture will have noted how extremely difficult it is even to get within sight of a bird of this sort.

Certain birds, unfortunately for themselves, have lost the power of flight without correspondingly increased powers of running, and have paid the penalty of extinction. Such an arrangement, as might be anticipated, was the result of evolution in islands devoid of any predatory ground-animals, and a classic example of it is afforded by the dodo and its allies, birds related to the pigeons. The dodo itself was a large and clumsy-looking species that at one time abounded in the island of Mauritius, which, like oceanic islands generally, possessed no native mammals, while its indigenous reptiles were only represented by lizards. The ubiquitous sailor, however, and the animals (especially swine) which he introduced, brought about the extinction of this helpless bird in less than a century after its first discovery in 1598. Its memory is now only kept green by a few contemporary drawings and descriptions, certain museum remains, and the proverb "as extinct as a dodo.” A similar fate must overtake any organism suddenly exposed to new and unfavorable conditions, if devoid of sufficient plasticity to rapidly accommodate itself to the altered environment.

The purpose of the underlined sentence is __________.

to provide an example likely familiar to readers of how effective a running bird’s defenses can be

to introduce a discussion of the land-rail and corn-crake

to make himself feel better about having never been able to catch a land-rail or corn-crake

to explain how other types of running birds differ from the African ostrich

to suggest that more people hunt land-rails and corn-crakes

Explanation

The underlined sentence appears at the end of the first paragraph and reads, “Anyone who has pursued our native land-rail or corn-crake with intent to capture will have noted how extremely difficult it is even to get within sight of a bird of this sort.”

This is the only sentence in the passage that mentions the land-rail and corn-crake, so “to introduce a discussion of the land-rail and corn-crake” cannot be the correct answer. The author doesn’t tell us that he himself has pursued a land-rail or corn-crake, and while one might infer this, he doesn’t say anything about having failed to catch one, so “to make himself feel better about having never been able to catch a land-rail or corn-crake” doesn’t seem to be the correct answer either. The answer choice “to suggest that more people hunt land-rails and corn-crakes “ cannot be correct, as the author isn’t urging the reader to do anything in this sentence; it is simply conveying information.

This leaves us with two answer choices: “to explain how other types of running birds differ from the African ostrich” and “to provide an example likely familiar to readers of how effective a running bird’s defenses can be.” While the first of these answer choices may seem correct at first glance, the author isn’t actually mentioning the land-rail and corn-crake to explain how other types of running birds differ from the African ostrich. He does this in a previous sentence. It is more accurate to say that the underlined sentence **“**provide\[s\] an example likely familiar to readers of how effective a running bird’s defenses can be.”

3

Adapted from “Birds in Retreat” in “Animal Defences—Active Defence” in Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by James Richard Ainsworth Davis (1903)

Among the large running birds are forms, like the African ostrich, in which the absence of powers of flight is largely compensated by the specialization of the legs for the purpose of rapid movement on the ground. For straightforward retreat in open country nothing could be more effective; but another kind of adaptation is required in birds like rails, which are deficient in powers of flight, and yet are able to run through thickly-growing vegetation with such rapidity as to commonly elude their enemies. This is rendered possible by the shape of their bodies, which are relatively narrow and flattened from side to side, so as to easily slip between the stems of grasses, rushes, and similar plants. Anyone who has pursued our native land-rail or corn-crake with intent to capture will have noted how extremely difficult it is even to get within sight of a bird of this sort.

Certain birds, unfortunately for themselves, have lost the power of flight without correspondingly increased powers of running, and have paid the penalty of extinction. Such an arrangement, as might be anticipated, was the result of evolution in islands devoid of any predatory ground-animals, and a classic example of it is afforded by the dodo and its allies, birds related to the pigeons. The dodo itself was a large and clumsy-looking species that at one time abounded in the island of Mauritius, which, like oceanic islands generally, possessed no native mammals, while its indigenous reptiles were only represented by lizards. The ubiquitous sailor, however, and the animals (especially swine) which he introduced, brought about the extinction of this helpless bird in less than a century after its first discovery in 1598. Its memory is now only kept green by a few contemporary drawings and descriptions, certain museum remains, and the proverb "as extinct as a dodo.” A similar fate must overtake any organism suddenly exposed to new and unfavorable conditions, if devoid of sufficient plasticity to rapidly accommodate itself to the altered environment.

The purpose of the underlined sentence is __________.

to provide an example likely familiar to readers of how effective a running bird’s defenses can be

to introduce a discussion of the land-rail and corn-crake

to make himself feel better about having never been able to catch a land-rail or corn-crake

to explain how other types of running birds differ from the African ostrich

to suggest that more people hunt land-rails and corn-crakes

Explanation

The underlined sentence appears at the end of the first paragraph and reads, “Anyone who has pursued our native land-rail or corn-crake with intent to capture will have noted how extremely difficult it is even to get within sight of a bird of this sort.”

This is the only sentence in the passage that mentions the land-rail and corn-crake, so “to introduce a discussion of the land-rail and corn-crake” cannot be the correct answer. The author doesn’t tell us that he himself has pursued a land-rail or corn-crake, and while one might infer this, he doesn’t say anything about having failed to catch one, so “to make himself feel better about having never been able to catch a land-rail or corn-crake” doesn’t seem to be the correct answer either. The answer choice “to suggest that more people hunt land-rails and corn-crakes “ cannot be correct, as the author isn’t urging the reader to do anything in this sentence; it is simply conveying information.

This leaves us with two answer choices: “to explain how other types of running birds differ from the African ostrich” and “to provide an example likely familiar to readers of how effective a running bird’s defenses can be.” While the first of these answer choices may seem correct at first glance, the author isn’t actually mentioning the land-rail and corn-crake to explain how other types of running birds differ from the African ostrich. He does this in a previous sentence. It is more accurate to say that the underlined sentence **“**provide\[s\] an example likely familiar to readers of how effective a running bird’s defenses can be.”

4

Adapted from “Birds in Retreat” in “Animal Defences—Active Defence” in Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by James Richard Ainsworth Davis (1903)

Among the large running birds are forms, like the African ostrich, in which the absence of powers of flight is largely compensated by the specialization of the legs for the purpose of rapid movement on the ground. For straightforward retreat in open country nothing could be more effective; but another kind of adaptation is required in birds like rails, which are deficient in powers of flight, and yet are able to run through thickly-growing vegetation with such rapidity as to commonly elude their enemies. This is rendered possible by the shape of their bodies, which are relatively narrow and flattened from side to side, so as to easily slip between the stems of grasses, rushes, and similar plants. Anyone who has pursued our native land-rail or corn-crake with intent to capture will have noted how extremely difficult it is even to get within sight of a bird of this sort.

Certain birds, unfortunately for themselves, have lost the power of flight without correspondingly increased powers of running, and have paid the penalty of extinction. Such an arrangement, as might be anticipated, was the result of evolution in islands devoid of any predatory ground-animals, and a classic example of it is afforded by the dodo and its allies, birds related to the pigeons. The dodo itself was a large and clumsy-looking species that at one time abounded in the island of Mauritius, which, like oceanic islands generally, possessed no native mammals, while its indigenous reptiles were only represented by lizards. The ubiquitous sailor, however, and the animals (especially swine) which he introduced, brought about the extinction of this helpless bird in less than a century after its first discovery in 1598. Its memory is now only kept green by a few contemporary drawings and descriptions, certain museum remains, and the proverb "as extinct as a dodo.” A similar fate must overtake any organism suddenly exposed to new and unfavorable conditions, if devoid of sufficient plasticity to rapidly accommodate itself to the altered environment.

The purpose of the underlined sentence is __________.

to provide an example likely familiar to readers of how effective a running bird’s defenses can be

to introduce a discussion of the land-rail and corn-crake

to make himself feel better about having never been able to catch a land-rail or corn-crake

to explain how other types of running birds differ from the African ostrich

to suggest that more people hunt land-rails and corn-crakes

Explanation

The underlined sentence appears at the end of the first paragraph and reads, “Anyone who has pursued our native land-rail or corn-crake with intent to capture will have noted how extremely difficult it is even to get within sight of a bird of this sort.”

This is the only sentence in the passage that mentions the land-rail and corn-crake, so “to introduce a discussion of the land-rail and corn-crake” cannot be the correct answer. The author doesn’t tell us that he himself has pursued a land-rail or corn-crake, and while one might infer this, he doesn’t say anything about having failed to catch one, so “to make himself feel better about having never been able to catch a land-rail or corn-crake” doesn’t seem to be the correct answer either. The answer choice “to suggest that more people hunt land-rails and corn-crakes “ cannot be correct, as the author isn’t urging the reader to do anything in this sentence; it is simply conveying information.

This leaves us with two answer choices: “to explain how other types of running birds differ from the African ostrich” and “to provide an example likely familiar to readers of how effective a running bird’s defenses can be.” While the first of these answer choices may seem correct at first glance, the author isn’t actually mentioning the land-rail and corn-crake to explain how other types of running birds differ from the African ostrich. He does this in a previous sentence. It is more accurate to say that the underlined sentence **“**provide\[s\] an example likely familiar to readers of how effective a running bird’s defenses can be.”

5

Adapted from Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by James Richard Ainsworth Davis (1903)

The examples of protective resemblance so far quoted are mostly permanent adaptations to one particular sort of surrounding. There are, however, numerous animals which possess the power of adjusting their color more or less rapidly so as to harmonize with a changing environment.

Some of the best known of these cases are found among those mammals and birds that inhabit countries more or less covered with snow during a part of the year. A good instance is afforded by the Irish or variable hare, which is chiefly found in Ireland and Scotland. In summer, this looks very much like an ordinary hare, though rather grayer in tint and smaller in size, but in winter it becomes white with the exception of the black tips to the ears. Investigations that have been made on the closely allied American hare seem to show that the phenomenon is due to the growth of new hairs of white hue.

The common stoat is subject to similar color change in the northern parts of its range. In summer it is of a bright reddish brown color with the exception of the under parts, which are yellowish white, and the end of the tail, which is black. But in winter, the entire coat, save only the tip of the tail, becomes white, and in that condition the animal is known as an ermine. A similar example is afforded by the weasel. The seasonal change in the vegetarian Irish hare is purely of protective character, but in such an actively carnivorous creature as a stoat or weasel, it is aggressive as well, rendering the animal inconspicuous to its prey.

A stoat might also be called __________.

an ermine, depending on its fur color

a weasel, depending on where it lives

a weasel, depending on its fur color

an ermine, depending on where it lives

a weasel, depending on what it eats

Explanation

The passage’s last paragraph provides the information we need to answer this question. The paragraph begins by describing “the common stoat.” Eventually, it says, “But in winter, the entire coat, save only the tip of the tail, becomes white, and in that condition the animal is known as an ermine.” While this sentence is followed by “A similar example is afforded by the weasel,” this means that the weasel is another example of an animal that changes its fur color, not that a stoat can be called a weasel. It means that a weasel is a distinct type of animal. The correct answer is that a stoat might also be called “an ermine, depending on its fur color.”

6

Adapted from Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by James Richard Ainsworth Davis (1903)

The examples of protective resemblance so far quoted are mostly permanent adaptations to one particular sort of surrounding. There are, however, numerous animals which possess the power of adjusting their color more or less rapidly so as to harmonize with a changing environment.

Some of the best known of these cases are found among those mammals and birds that inhabit countries more or less covered with snow during a part of the year. A good instance is afforded by the Irish or variable hare, which is chiefly found in Ireland and Scotland. In summer, this looks very much like an ordinary hare, though rather grayer in tint and smaller in size, but in winter it becomes white with the exception of the black tips to the ears. Investigations that have been made on the closely allied American hare seem to show that the phenomenon is due to the growth of new hairs of white hue.

The common stoat is subject to similar color change in the northern parts of its range. In summer it is of a bright reddish brown color with the exception of the under parts, which are yellowish white, and the end of the tail, which is black. But in winter, the entire coat, save only the tip of the tail, becomes white, and in that condition the animal is known as an ermine. A similar example is afforded by the weasel. The seasonal change in the vegetarian Irish hare is purely of protective character, but in such an actively carnivorous creature as a stoat or weasel, it is aggressive as well, rendering the animal inconspicuous to its prey.

A stoat might also be called __________.

an ermine, depending on its fur color

a weasel, depending on where it lives

a weasel, depending on its fur color

an ermine, depending on where it lives

a weasel, depending on what it eats

Explanation

The passage’s last paragraph provides the information we need to answer this question. The paragraph begins by describing “the common stoat.” Eventually, it says, “But in winter, the entire coat, save only the tip of the tail, becomes white, and in that condition the animal is known as an ermine.” While this sentence is followed by “A similar example is afforded by the weasel,” this means that the weasel is another example of an animal that changes its fur color, not that a stoat can be called a weasel. It means that a weasel is a distinct type of animal. The correct answer is that a stoat might also be called “an ermine, depending on its fur color.”

7

Adapted from “Humming-Birds: As Illustrating the Luxuriance of Tropical Nature” in Tropical Nature, and Other Essays by Alfred Russel Wallace (1878)

The food of hummingbirds has been a matter of much controversy. All the early writers down to Buffon believed that they lived solely on the nectar of flowers, but since that time, every close observer of their habits maintains that they feed largely, and in some cases wholly, on insects. Azara observed them on the La Plata in winter taking insects out of the webs of spiders at a time and place where there were no flowers. Bullock, in Mexico, declares that he saw them catch small butterflies, and that he found many kinds of insects in their stomachs. Waterton made a similar statement. Hundreds and perhaps thousands of specimens have since been dissected by collecting naturalists, and in almost every instance their stomachs have been found full of insects, sometimes, but not generally, mixed with a proportion of honey. Many of them in fact may be seen catching gnats and other small insects just like fly-catchers, sitting on a dead twig over water, darting off for a time in the air, and then returning to the twig. Others come out just at dusk, and remain on the wing, now stationary, now darting about with the greatest rapidity, imitating in a limited space the evolutions of the goatsuckers, and evidently for the same end and purpose. Mr. Gosse also remarks, ” All the hummingbirds have more or less the habit, when in flight, of pausing in the air and throwing the body and tail into rapid and odd contortions. This is most observable in the Polytmus, from the effect that such motions have on the long feathers of the tail. That the object of these quick turns is the capture of insects, I am sure, having watched one thus engaged pretty close to me.”

How does the quotation from Mr. Gosse relate to the evidence provided by other scientists earlier in the passage?

It supports the same conclusions that the previous evidence supports.

It contradicts the previous evidence and supports a different hypothesis.

It has nothing to do with the previous evidence.

It suggests that some of the previous evidence may be true, but some may be false.

It suggests that the earlier evidence applies not only to hummingbirds but to another type of bird as well.

Explanation

Let’s consider what Mr. Gosse is saying. The passage says, “Mr. Gosse also remarks, ‘All the hummingbirds have more or less the habit, when in flight, of pausing in the air and throwing the body and tail into rapid and odd contortions. This is most observable in the Polytmus, from the effect that such motions have on the long feathers of the tail. That the object of these quick turns is the capture of insects, I am sure, having watched one thus engaged pretty close to me.’” Paraphrasing that, Mr. Gosse is saying that he has seen hummingbirds contort themselves in the air and he’s pretty sure they’re doing this in order to catch insects. The evidence provided by scientists earlier in the passage supports the idea that hummingbirds eat insects, just like Mr. Gosse’s does. We can’t say that Gosse’s evidence contradicts the earlier evidence, suggests that some of it may be false, or has nothing to do with the previous evidence. It also doesn’t suggest that the previous evidence can be applied to birds other than hummingbirds, because Mr. Gosse says that he is only discussing hummingbirds and we are to infer that the Polytmus is a hummingbird. So, the correct answer is that “it supports the same conclusions that the previous evidence supports.”

8

Adapted from “Humming-Birds: As Illustrating the Luxuriance of Tropical Nature” in Tropical Nature, and Other Essays by Alfred Russel Wallace (1878)

The food of hummingbirds has been a matter of much controversy. All the early writers down to Buffon believed that they lived solely on the nectar of flowers, but since that time, every close observer of their habits maintains that they feed largely, and in some cases wholly, on insects. Azara observed them on the La Plata in winter taking insects out of the webs of spiders at a time and place where there were no flowers. Bullock, in Mexico, declares that he saw them catch small butterflies, and that he found many kinds of insects in their stomachs. Waterton made a similar statement. Hundreds and perhaps thousands of specimens have since been dissected by collecting naturalists, and in almost every instance their stomachs have been found full of insects, sometimes, but not generally, mixed with a proportion of honey. Many of them in fact may be seen catching gnats and other small insects just like fly-catchers, sitting on a dead twig over water, darting off for a time in the air, and then returning to the twig. Others come out just at dusk, and remain on the wing, now stationary, now darting about with the greatest rapidity, imitating in a limited space the evolutions of the goatsuckers, and evidently for the same end and purpose. Mr. Gosse also remarks, ” All the hummingbirds have more or less the habit, when in flight, of pausing in the air and throwing the body and tail into rapid and odd contortions. This is most observable in the Polytmus, from the effect that such motions have on the long feathers of the tail. That the object of these quick turns is the capture of insects, I am sure, having watched one thus engaged pretty close to me.”

How does the quotation from Mr. Gosse relate to the evidence provided by other scientists earlier in the passage?

It supports the same conclusions that the previous evidence supports.

It contradicts the previous evidence and supports a different hypothesis.

It has nothing to do with the previous evidence.

It suggests that some of the previous evidence may be true, but some may be false.

It suggests that the earlier evidence applies not only to hummingbirds but to another type of bird as well.

Explanation

Let’s consider what Mr. Gosse is saying. The passage says, “Mr. Gosse also remarks, ‘All the hummingbirds have more or less the habit, when in flight, of pausing in the air and throwing the body and tail into rapid and odd contortions. This is most observable in the Polytmus, from the effect that such motions have on the long feathers of the tail. That the object of these quick turns is the capture of insects, I am sure, having watched one thus engaged pretty close to me.’” Paraphrasing that, Mr. Gosse is saying that he has seen hummingbirds contort themselves in the air and he’s pretty sure they’re doing this in order to catch insects. The evidence provided by scientists earlier in the passage supports the idea that hummingbirds eat insects, just like Mr. Gosse’s does. We can’t say that Gosse’s evidence contradicts the earlier evidence, suggests that some of it may be false, or has nothing to do with the previous evidence. It also doesn’t suggest that the previous evidence can be applied to birds other than hummingbirds, because Mr. Gosse says that he is only discussing hummingbirds and we are to infer that the Polytmus is a hummingbird. So, the correct answer is that “it supports the same conclusions that the previous evidence supports.”

9

Adapted from “Humming-Birds: As Illustrating the Luxuriance of Tropical Nature” in Tropical Nature, and Other Essays by Alfred Russel Wallace (1878)

The food of hummingbirds has been a matter of much controversy. All the early writers down to Buffon believed that they lived solely on the nectar of flowers, but since that time, every close observer of their habits maintains that they feed largely, and in some cases wholly, on insects. Azara observed them on the La Plata in winter taking insects out of the webs of spiders at a time and place where there were no flowers. Bullock, in Mexico, declares that he saw them catch small butterflies, and that he found many kinds of insects in their stomachs. Waterton made a similar statement. Hundreds and perhaps thousands of specimens have since been dissected by collecting naturalists, and in almost every instance their stomachs have been found full of insects, sometimes, but not generally, mixed with a proportion of honey. Many of them in fact may be seen catching gnats and other small insects just like fly-catchers, sitting on a dead twig over water, darting off for a time in the air, and then returning to the twig. Others come out just at dusk, and remain on the wing, now stationary, now darting about with the greatest rapidity, imitating in a limited space the evolutions of the goatsuckers, and evidently for the same end and purpose. Mr. Gosse also remarks, ” All the hummingbirds have more or less the habit, when in flight, of pausing in the air and throwing the body and tail into rapid and odd contortions. This is most observable in the Polytmus, from the effect that such motions have on the long feathers of the tail. That the object of these quick turns is the capture of insects, I am sure, having watched one thus engaged pretty close to me.”

How does the quotation from Mr. Gosse relate to the evidence provided by other scientists earlier in the passage?

It supports the same conclusions that the previous evidence supports.

It contradicts the previous evidence and supports a different hypothesis.

It has nothing to do with the previous evidence.

It suggests that some of the previous evidence may be true, but some may be false.

It suggests that the earlier evidence applies not only to hummingbirds but to another type of bird as well.

Explanation

Let’s consider what Mr. Gosse is saying. The passage says, “Mr. Gosse also remarks, ‘All the hummingbirds have more or less the habit, when in flight, of pausing in the air and throwing the body and tail into rapid and odd contortions. This is most observable in the Polytmus, from the effect that such motions have on the long feathers of the tail. That the object of these quick turns is the capture of insects, I am sure, having watched one thus engaged pretty close to me.’” Paraphrasing that, Mr. Gosse is saying that he has seen hummingbirds contort themselves in the air and he’s pretty sure they’re doing this in order to catch insects. The evidence provided by scientists earlier in the passage supports the idea that hummingbirds eat insects, just like Mr. Gosse’s does. We can’t say that Gosse’s evidence contradicts the earlier evidence, suggests that some of it may be false, or has nothing to do with the previous evidence. It also doesn’t suggest that the previous evidence can be applied to birds other than hummingbirds, because Mr. Gosse says that he is only discussing hummingbirds and we are to infer that the Polytmus is a hummingbird. So, the correct answer is that “it supports the same conclusions that the previous evidence supports.”

10

Adapted from “Humming-Birds: As Illustrating the Luxuriance of Tropical Nature” in Tropical Nature, and Other Essays by Alfred Russel Wallace (1878)

The food of hummingbirds has been a matter of much controversy. All the early writers down to Buffon believed that they lived solely on the nectar of flowers, but since that time, every close observer of their habits maintains that they feed largely, and in some cases wholly, on insects. Azara observed them on the La Plata in winter taking insects out of the webs of spiders at a time and place where there were no flowers. Bullock, in Mexico, declares that he saw them catch small butterflies, and that he found many kinds of insects in their stomachs. Waterton made a similar statement. Hundreds and perhaps thousands of specimens have since been dissected by collecting naturalists, and in almost every instance their stomachs have been found full of insects, sometimes, but not generally, mixed with a proportion of honey. Many of them in fact may be seen catching gnats and other small insects just like fly-catchers, sitting on a dead twig over water, darting off for a time in the air, and then returning to the twig. Others come out just at dusk, and remain on the wing, now stationary, now darting about with the greatest rapidity, imitating in a limited space the evolutions of the goatsuckers, and evidently for the same end and purpose. Mr. Gosse also remarks, ” All the hummingbirds have more or less the habit, when in flight, of pausing in the air and throwing the body and tail into rapid and odd contortions. This is most observable in the Polytmus, from the effect that such motions have on the long feathers of the tail. That the object of these quick turns is the capture of insects, I am sure, having watched one thus engaged pretty close to me.”

Which of the following inferences does the passage expect its readers to make?

If a hummingbird consumes flower nectar, this nectar will turn into the honey that can be found in its stomach.

If a hummingbird eats gnats, it will not eat honey.

Scientists rarely learn about hummingbirds by dissecting them.

Fly-catchers are a type of insect.

The author is the first scientist to ever have investigated what hummingbirds eat.

Explanation

Let’s consider each of the answer choices to identify the correct one.

“The author is the first scientist to ever have investigated what hummingbirds eat.” - This cannot be true, because the author begins the passage by saying “The food of hummingbirds has been a matter of much controversy. All the early writers down to Buffon believed that they lived solely on the nectar of flowers, but since that time, every close observer of their habits maintains that they feed largely, and in some cases wholly, on insects.” He also cites numerous other scientists’ opinions throughout the passage, so he can’t be the first person to have investigated what hummingbirds eat.

“Fly-catchers are a type of insect.” - The passage mentions fly-catchers in the following sentence: “Many \[hummingbirds\] in fact may be seen catching gnats and other small insects just like fly-catchers, sitting on a dead twig over water, darting off for a time in the air, and then returning to the twig.” This is a tricky answer choice in that it’s easy to misread the sentence and think that “just like flycatchers” refers to “other small insects” when in fact it refers to the act of “catching.” The sentence is saying that hummingbirds catch insects in the same manner as fly-catchers, not that fly-catchers are a type of insect. Plus, we are being asked to identify an inference readers are expected to make, and if this sentence did mean that fly-catchers were insects, it would be overtly telling us this, and there would be nothing we’d have to infer.

“Scientists rarely learn about hummingbirds by dissecting them.” - This answer choice is proven wrong by the following sentence: “Hundreds and perhaps thousands of specimens have since been dissected by collecting naturalists, and in almost every instance their stomachs have been found full of insects, sometimes, but not generally, mixed with a proportion of honey.”

“If a hummingbird eats gnats, it will not eat honey.” - Given that the questions of whether hummingbirds eat insects or honey and in what proportions is the topic of the passage, it may be easy to choose this answer choice because it seems like the one closest to the passage’s main idea; however, nothing in the passage supports this assertion.

“If a hummingbird consumes flower nectar, this nectar will turn into the honey that can be found in its stomach.” - This is the correct answer! The author initially states that “All the early writers down to Buffon believed that \[hummingbirds\] lived solely on the nectar of flowers”; however, he later states that “Hundreds and perhaps thousands of specimens have since been dissected by collecting naturalists, and in almost every instance their stomachs have been found full of insects, sometimes, but not generally, mixed with a proportion of honey.” The author does not address the idea that flower nectar and honey could be different substances, and instead expects the reader to treat these as one source of food.

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