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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.
One of the main differences between an ostrich and a rail, according to the passage, is __________.
Ostriches and rails are discussed in the first paragraph. The author says that “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.” The passage then goes on to detail how rails have thin bodies that allow them to dart through the grass. This means that the correct answer is “ostriches run over open terrain whereas rails run through thick grass.”
The passage is describing the rail, a type of bird, and not using the word “rail” to describe part of a train track or a barrier on an elevated area, so “ostriches are living things whereas rails are inanimate objects” cannot be correct. Ostriches are never said to be smaller than rails or predators, so neither “ostriches are smaller than rails” nor “ostriches use their running abilities to catch prey, whereas rails use their running abilities to avoid predators” can be correct. Finally, rails are said to live in areas containing and have adapted to “thickly-growing vegetation” and ostriches are said to have developed a different adaptation suited to “open country,” so “ostriches live in grassy areas whereas rails live in the desert” cannot be correct either.
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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.
How does the second paragraph relate to the first paragraph?
Examining the two paragraphs, one can find that the first one talks about ostriches and rails, two types of flightless birds that adapted in specific ways to be good at fleeing predators. The second paragraph tells the story of the dodo, a flightless bird that did not have time to develop such adaptations. From here, we can pick out the correct answer: “The first paragraph describes flightless birds that learned to defend themselves from predators by fleeing them; the second paragraph describes a flightless bird that did not adapt in this way.”
As for the other answer choices, nothing in the passage discusses people eating birds, so we can ignore the answer choice “The first paragraph describes birds people eat; the second describes birds people do not eat.” The answer choice “The first paragraph describes a type of flightless birds that has gone extinct; the second describes species of flightless birds that are still living” would be correct if it flipped around the paragraphs to which it refers, but as it is written, it is incorrect. The passage doesn’t say anything about the predators of flightless birds in the first paragraph or the prey of flightless birds in either paragraph, so “The first paragraph discusses predators of flightless birds, the second describes prey of flightless birds” cannot be correct, and since the first paragraph does not provide a personal anecdote, “The first paragraph provides a personal anecdote while the second paragraph provides historical information” cannot be correct either.
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Adapted from "Recent Views as to Direct Action of Light on the Colors of Flowers and Fruits" in Tropical Nature, and Other Essays by Alfred Russel Wallace (1878)
The theory that the brilliant colors of flowers and fruits is due to the direct action of light has been supported by a recent writer by examples taken from the arctic instead of from the tropical flora. In the arctic regions, vegetation is excessively rapid during the short summer, and this is held to be due to the continuous action of light throughout the long summer days. “The further we advance towards the north, the more the leaves of plants increase in size as if to absorb a greater proportion of the solar rays. M. Grisebach says that during a journey in Norway he observed that the majority of deciduous trees had already, at the 60th degree of latitude, larger leaves than in Germany, while M. Ch. Martins has made a similar observation as regards the leguminous plants cultivated in Lapland.” The same writer goes on to say that all the seeds of cultivated plants acquire a deeper color the further north they are grown, white haricots becoming brown or black, and white wheat becoming brown, while the green color of all vegetation becomes more intense. The flowers also are similarly changed: those which are white or yellow in central Europe becoming red or orange in Norway. This is what occurs in the Alpine flora, and the cause is said to be the same in both—the greater intensity of the sunlight. In the one the light is more persistent, in the other more intense because it traverses a less thickness of atmosphere.
Admitting the facts as above stated to be in themselves correct, they do not by any means establish the theory founded on them; and it is curious that Grisebach, who has been quoted by this writer for the fact of the increased size of the foliage, gives a totally different explanation of the more vivid colors of Arctic flowers. He says, “We see flowers become larger and more richly colored in proportion as, by the increasing length of winter, insects become rarer, and their cooperation in the act of fecundation is exposed to more uncertain chances.” (Vegetation du Globe, col. i. p. 61—French translation.) This is the theory here adopted to explain the colors of Alpine plants, and we believe there are many facts that will show it to be the preferable one. The statement that the white and yellow flowers of temperate Europe become red or golden in the Arctic regions must we think be incorrect. By roughly tabulating the colors of the plants given by Sir Joseph Hooker as permanently Arctic, we find among fifty species with more or less conspicuous flowers, twenty-five white, twelve yellow, eight purple or blue, three lilac, and two red or pink; showing a very similar proportion of white and yellow flowers to what obtains further south.
In this passage, the author __________.
Answering this question requires you to read closely, as many theories are mentioned throughout the passage and keeping track of them can be quite challenging. In the first paragraph, the writer quotes a "recent writer," who then quotes evidence in the form of observations by M. Grisebach and M. Ch. Martins. In the second paragraph, the writer says that he agrees with the evidence of the "recent writer" (in other words, Grisebach and Martins), but not with the theory the "recent writer" has come up with to explain that evidence. So, the author disagrees with the "recent writer," but agrees with Grisebach, because the author goes on to quote Grisebach's own theory, with which the author agrees.
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"Darwin and His Influence" by Joseph Ritchie (2014)
In this passage, “selection” refers to traits that are selected for and passed on to later generations, and “species” refers to organisms that share a common ancestor and can produce viable offspring with one another.
Early in the nineteenth century, scientists sought to understand the differences in the earth’s flora and fauna from their archeological ancestors. The prevailing view at the time was that the differences between current and previous species were unremarkable deviations from their Platonic ideal forms. This theory hinged upon the ideals of the religious-based “created kinds” theory, which state that individuals of today are products of the organisms that were present at the earth’s creation, the result of an intelligent designer. Furthermore, these individuals believed that the differences between organisms could be explained by unseen geological and astrological forces acting on organisms slowly, throughout time. Other scientists also believed that individuals had the ability to change within their lifetimes and pass on traits to their offspring efficiently and quickly through a single generation.
Charles Darwin and other biologists, such as Alfred Wallace, were not greatly influenced by these views and hypotheses. Their propositions stated that species evolve over many generations, due to the selective pressures of their given environments. This evolution could result in the generation of divergent traits, as well as speciation and separation from the original ancestral species. The concept that organisms were not finite or present since creation was very controversial to the scientists of the period. Some saw such an idea as unsupportable, while others perceived it as heretical and fanatical.
Darwin set out to find support for his theory through his work, On the Origins of Species by Means of Natural Selection. He was influenced by archeological discoveries of species, which appeared to have vastly different physiological appearances from present-day organisms. Darwin decided to sail around the world on a Royal Navy ship named the H.M.S. Beagle. During his travels, he was taken to the Pacific islands of the Galapagos archipelago. The volcanic islands followed a patterned distribution on either side of the Equator. The landscapes of each island varied, with different observable flora and fauna. Through scientific observations, Darwin noticed subtle variations of finches on different islands. Some finches had large hard beaks, while others had slender beaks. Beaks were differentiated from island to island. After careful study, Darwin noticed that the beaks seemed to match the food source on each island. The large beaks were specialized for breaking open hard-shelled nuts, while the slender beaks were specialized for eating certain fruits that were abundant. Darwin hypothesized that an ancestral species of finch landed on the islands, and that over generations they became adapted to the locally abundant food sources.
Darwin compiled multiple instances of natural selection and incorporated discoveries made by archeologists and physiologists. He surmised that species evolve over time due to the selective pressures of their respective habitats. These events occur slowly over many generations. Each species selects for advantageous traits among its members. Over time, traits selected as advantageous by environmental pressures and stressors become commonplace in the species. This niche-forming process specializes species by rewarding those with traits most suitable for reproductive success. These traits may progress into speciation of the original species, which results in the eventual development of an entirely new species. Darwin’s theory was met with opposition at the time of its publication, and the theory of evolution remains a controversial topic in several arenas of debate.
The main difference between the "created kinds" theory and natural selection is represented by which of the following statements?
The "created kinds" theory suggests a finite number of species on earth while natural selection assumes species evolve.
This is the correct answer because it represents the main differences of the theories. Natural selection suggests that species evolve, change, and divert from themselves. This means that there is an infinite number of possible divergences not a finite amount as suggested by the "created kinds" model. No evidence in the passage suggests that either theory is correct, butter supported, religious based, or the foundation of Darwin's theory.
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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 does the author contrast in this passage?
Nowhere in the passage is the feeding of hummingbirds by humans mentioned, so “The results of feeding a hummingbird insects and the results of feeding a hummingbird flower nectar” cannot be correct. While a hummingbird with a long tail, the Polytmus, is mentioned, it is not contrasted with any short-tailed hummingbirds. The author appears to agree with Mr. Gosse’s opinion about what hummingbirds eat, so “The author’s opinion about what hummingbirds eat and Mr. Gosse’s opinion about what hummingbirds eat” cannot be correct either. This leaves us with “Hummingbirds that eat flower nectar and hummingbirds that eat insects” and “the beliefs of historical scientists and the beliefs of scientists of the author’s time.” While the passage is concerned with what hummingbirds eat, it doesn’t suggest that some types of hummingbirds eat only nectar and others eat only insects. Hummingbirds are considered as an entire group; they’re never divided into “hummingbirds that eat insects” and “hummingbirds that eat flower nectar.” This leaves us with one answer choice, the correct one: “The beliefs of historical scientists and the beliefs of scientists of the author’s time.” These beliefs are contrasted in the paragraph’s second sentence: “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.”
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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.”
What do Azara, Bullock, and Waterton have in common?
Azara, Bullock, and Waterton are all mentioned near the beginning of the passage. The author writes, “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 then mentioned the following:
(1) "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."
(2) "Bullock, in Mexico, declares that he saw them catch small butterflies, and that he found many kinds of insects in their stomachs."
(3) **"**Waterton made a similar statement."
The author is suggesting that Azara, Bullock, and Waterton fall into the group of “every close observer of their habits.” The three also make statements about hummingbirds. From this, we can narrow down our answers to three choices: that Azara, Bullock, and Waterton are critics of the author, scientists who think hummingbirds eat insects, or scientists who think hummingbirds eat flower nectar. Nowhere in the passage do the statements made by these writers appear to contradict the author’s opinion, so we can discard the idea that Azara, Bullock, and Waterton are critics of the author. So, are they saying that hummingbirds eat flower nectar or insects? They author says that early observers of hummingbirds thought that they eat flower nectar, but that more recent scientists—like the three quoted—think that they eat insects. The statements made by each also relate to hummingbirds eating insects, so the correct answer is “They are all scientists who think hummingbirds eat insects.”
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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?
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.”
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Adapted from “Introduced Species That Have Become Pests” in Our Vanishing Wild Life, Its Extermination and Protection by William Temple Hornaday (1913)
The man who successfully transplants or "introduces" into a new habitat any persistent species of living thing assumes a very grave responsibility. Every introduced species is doubtful gravel until panned out. The enormous losses that have been inflicted upon the world through the perpetuation of follies with wild vertebrates and insects would, if added together, be enough to purchase a principality. The most aggravating feature of these follies in transplantation is that never yet have they been made severely punishable. We are just as careless and easygoing on this point as we were about the government of the Yellowstone Park in the days when Howell and other poachers destroyed our first national bison herd, and when caught red-handed—as Howell was, skinning seven Park bison cows—could not be punished for it, because there was no penalty prescribed by any law. Today, there is a way in which any revengeful person could inflict enormous damage on the entire South, at no cost to himself, involve those states in enormous losses and the expenditure of vast sums of money, yet go absolutely unpunished!
The gypsy moth is a case in point. This winged calamity was imported at Maiden, Massachusetts, near Boston, by a French entomologist, Mr. Leopold Trouvelot, in 1868 or 69. History records the fact that the man of science did not purposely set free the pest. He was endeavoring with live specimens to find a moth that would produce a cocoon of commercial value to America, and a sudden gust of wind blew out of his study, through an open window, his living and breeding specimens of the gypsy moth. The moth itself is not bad to look at, but its larvae is a great, overgrown brute with an appetite like a hog. Immediately Mr. Trouvelot sought to recover his specimens, and when he failed to find them all, like a man of real honor, he notified the State authorities of the accident. Every effort was made to recover all the specimens, but enough escaped to produce progeny that soon became a scourge to the trees of Massachusetts. The method of the big, nasty-looking mottled-brown caterpillar was very simple. It devoured the entire foliage of every tree that grew in its sphere of influence.
The gypsy moth spread with alarming rapidity and persistence. In course of time, the state authorities of Massachusetts were forced to begin a relentless war upon it, by poisonous sprays and by fire. It was awful! Up to this date (1912) the New England states and the United States Government service have expended in fighting this pest about $7,680,000!
The spread of this pest has been retarded, but the gypsy moth never will be wholly stamped out. Today it exists in Rhode Island, Connecticut, and New Hampshire, and it is due to reach New York at an early date. It is steadily spreading in three directions from Boston, its original point of departure, and when it strikes the State of New York, we, too, will begin to pay dearly for the Trouvelot experiment.
Howell’s story is different from that of Mr. Trouvelot’s in that __________.
According to the passage, what did Howell do? He was caught skinning bison in Yellowstone National Park and there was no way to punish him, a point about which the author is frustrated. What did Mr. Trouvelot do? He accidentally released gypsy moths into the United States, where they’ve caused a lot of trouble since. Nothing in the passage says that Mr. Trouvelot worked in a group, so we can eliminate the answer “Howell acted alone while Mr. Trouvelot worked with a group.” Similarly, while the passage says that Mr. Trouvelot was a scientist (an entomologist), nothing says that Howell worked for a zoo, so “Howell worked for a zoo while Trouvelot was a scientist” can’t be correct. The author brings up Howell’s story as an example of someone who couldn’t be punished by law for what the author considers an egregiously bad act, so “Howell could be punished by law, while Mr. Trouvelot could not” can’t be correct either. Howell’s story has nothing to do with insects and Mr. Trouvelot released his gypsy moths on accident, so “Howell sought to capture insects while Trouvelot sought to release them” cannot be the correct answer. This leaves us with one answer choice, the correct one: “Howell acted purposely while Trouvelot introduced the moths by accident.”
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Adapted from “Feathers of Sea Birds and Wild Fowl for Bedding” from The Utility of Birds by Edward Forbush (ed. 1922)
In the colder countries of the world, the feathers and down of waterfowl have been in great demand for centuries as filling for beds and pillows. Such feathers are perfect non-conductors of heat, and beds, pillows, or coverlets filled with them represent the acme of comfort and durability. The early settlers of New England saved for such purposes the feathers and down from the thousands of wild-fowl which they killed, but as the population increased in numbers, the quantity thus furnished was insufficient, and the people sought a larger supply in the vast colonies of ducks and geese along the Labrador coast.
The manner in which the feathers and down were obtained, unlike the method practiced in Iceland, did not tend to conserve and protect the source of supply. In Iceland, the people have continued to receive for many years a considerable income by collecting eider down, but there they do not “kill the goose that lays the golden eggs.” Ducks line their nests with down plucked from their own breasts and that of the eider is particularly valuable for bedding. In Iceland, these birds are so carefully protected that they have become as tame and unsuspicious as domestic fowls In North America. Where they are constantly hunted they often conceal their nests in the midst of weeds or bushes, but in Iceland, they make their nests and deposit their eggs in holes dug for them in the sod. A supply of the ducks is maintained so that the people derive from them an annual income.
In North America, quite a different policy was pursued. The demand for feathers became so great in the New England colonies about the middle of the eighteenth century that vessels were fitted out there for the coast of Labrador for the express purpose of securing the feathers and down of wild fowl. Eider down having become valuable and these ducks being in the habit of congregating by thousands on barren islands of the Labrador coast, the birds became the victims of the ships’ crews. As the ducks molt all their primary feathers at once in July or August and are then quite incapable of flight and the young birds are unable to fly until well grown, the hunters were able to surround the helpless birds, drive them together, and kill them with clubs. Otis says that millions of wildfowl were thus destroyed and that in a few years their haunts were so broken up by this wholesale slaughter and their numbers were so diminished that feather voyages became unprofitable and were given up.
This practice, followed by the almost continual egging, clubbing, shooting, etc. by Labrador fishermen, may have been a chief factor in the extinction of the Labrador duck, that species of supposed restricted breeding range. No doubt had the eider duck been restricted in its breeding range to the islands of Labrador, it also would have been exterminated long ago.
Which of the following does the passage directly compare?
Of the given answer choices, the passage only compares “the nesting habits of hunted and protected ducks.” It does this when the author says, “In Iceland, these birds are so carefully protected that they have become as tame and unsuspicious as domestic fowls In North America. Where they are constantly hunted they often conceal their nests in the midst of weeds or bushes, but in Iceland, they make their nests and deposit their eggs in holes dug for them in the sod.” The price of down is never mentioned in the passage, and while feathers and down are both mentioned, they are not compared. Similarly, the use of eider down in bedding is mentioned, but its use in North America and in Iceland isn’t compared. Finally, while ducks that nest on the Labrador coast and ducks that nest in Iceland are each described, they are not directly compared.
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Adapted from An Introduction to Astronomy by Forest Ray Moulton (1916 ed.)
The ancient Greeks, at a period four or five hundred years preceding the common era, definitely undertook to find from systematic observation how celestial phenomena follow one another. They determined very accurately the number of days in the year, the period of the moon's revolution, and the paths of the sun and the moon among the stars; they correctly explained the cause of eclipses and learned how to predict them with a considerable degree of accuracy; they undertook to measure the distances to the heavenly bodies, and to work out a complete system that would represent their motions. The idea was current among the Greek philosophers that the earth was spherical, that it turned on its axis, and, among some of them, that it revolved around the sun. They had true science in the modern acceptance of the term, but it was largely confined to the relations among celestial phenomena.
The conception that the heavens are orderly, which they definitely formulated and acted on with remarkable success, has been extended, especially in the last two centuries, so as to include the whole universe. The extension was first made to the inanimate world and then to the more complicated phenomena associated with living beings. Every increase in carefully recorded experience has confirmed and strengthened the belief that nature is perfectly orderly, until now every one who has had an opportunity of becoming familiar with any science is firmly convinced of the truth of this principle, which is the basis of all science.
Which best describes the contrast between modern and ancient science?
This selection does not do much to contrast the two sciences, as it is focusing on the character of Greek science in general, particularly its concern with celestial bodies and their motions. However, at the end of the first paragraph, there is a helpful sentence: "They had true science in the modern acceptance of the term, but it was largely confined to the relations among celestial phenomena." This implies that they had only one "real" branch of science, namely that which was "confined to the relations among celestial phenomena." The implication is that in contrast with this single science, modernity has a number of different sciences.
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"Interpreting the Copernican Revolution" by Matthew Minerd (2014)
The expressions of one discipline can often alter the way that other subjects understand themselves. Among such cases are numbered the investigations of Nicolaus Copernicus. Copernicus is best known for his views concerning heliocentrism, a view which eventually obliterated many aspects of the ancient/medieval worldview, at least from the standpoint of physical science. It had always been the natural view of mankind that the earth stood at the center of the universe, a fixed point in reference to the rest of the visible bodies. The sun, stars, and planets all rotated around the earth.
With time, this viewpoint became one of the major reference points for modern life. It provided a provocative image that was used—and often abused—by many people for various purposes. For those who wished to weaken the control of religion on mankind, it was said that the heliocentric outlook proved man’s insignificance. In contrast with earlier geocentrism, heliocentrism was said to show that man is not the center of the universe. He is merely one small being in the midst of a large cosmos. However, others wished to use the “Copernican Revolution” in a very different manner. These thinkers wanted to show that there was another “recentering” that had to happen. Once upon a time, we talked about the world. Now, however, it was necessary to talk of man as the central reference point. Just as the solar system was “centered” on the sun, so too should the sciences be centered on the human person.
However, both of these approaches are fraught with problems. Those who wished to undermine the religious mindset rather misunderstood the former outlook on the solar system. The earlier geocentric mindset did not believe that the earth was the most important body in the heavens. Instead, many ancient and medieval thinkers believed that the highest “sphere” above the earth was the most important being in the physical universe. Likewise, the so-called “Copernican Revolution” in physics was different from the one applied to the human person. Copernicus’ revolution showed that the human point of view was not the center, whereas the later forms of “Copernican revolution” wished to show just the opposite.
Of course, there are many complexities in the history of such important changes in scientific outlook. Nevertheless, it is fascinating to see the wide-reaching effects of such discoveries, even when they have numerous, ambiguous effects.
How are two uses of the image of heliocentrism contrasted in this passage?
The general contrast is between "man, the speck on a rock" and "man, the center of all things." The idea for one view is that the human person is insignificant in comparison to the rest of the universe, which dwarfs his little life on Earth. The other view makes the human person so significant that the study of human life is central.
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"Comparing Technologies: A Difficult Endeavor" by Matthew Minerd (2014)
Comparisons of technology are often difficult to make, not only because of the rapid pace of improvements but also because of the many new applications that are available as time progresses. If we were to consider the contemporary graphing calculator and the calculation capacities of computing machines from fifty years ago, there would be astounding improvements between these two devices. However, the improvements are not reduced merely to speed improvements. A graphing calculator also has numerous output capacities that far exceed those available much older computers, none of which had the ability to represent their output in any manner even closely resembling that of contemporary devices. Merely consider the display capacities of such a device. These enable users to input many new kinds of information, enabling design engineers to design new hardware functions to match the new means of collecting user input.
The situation is even more obvious when one considers the numerous functions performed by a modern “smartphone.” These devices are equipped with a panoply of features. With all of these new functions come many new types of computational capabilities as well. In order to process images quickly, specialized hardware must be designed and software written for it in order to ensure that there are few issues with the phone’s operation. Indeed, the whole “real time” nature of telecommunications has exerted numerous pressures on the designers of computing devices. Layers of complexity, at all levels of production and development, are required to ensure that the phone can function in a synchronous manner. Gone are the days of asynchronous processing, when the computer user entered data into a mainframe, only to wait for a period of time before the processing results were provided. Today, even the smallest of digital devices must provide seamless service for users. The effects of this requirement are almost beyond number.
Which of the following best describes the contrast between newer and older calculating devices?
In the selection, there are two key sentences: "However, the improvements are not reduced merely to speed improvements. A graphing calculator also has numerous output capacities that far exceed those available much older computers." The passage marks two points regarding the difference between the older and newer devices. They differ both with regard to speed and their ability to output data. The answer that speaks of having differing "capabilities" captures the distinction in output well enough for our answer. The other answers either bring in data not listed in our passage or are too narrow in scope.
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"Abstraction in the Sciences" by Matthew Minerd (2014)
Thinking “abstractly” is not a term that means quite the same thing in all of the sciences. Although we rarely think about this, it plays a key role in almost all of our day-to-day thought. Consider a zoologist working in a lab with many animals. When she is studying any individual tiger, she is not completely worried about the particular tiger—at least not primarily. Instead, she is trying to figure out certain characteristics of tigers in general. By meticulous testing, the zoologist carefully works out the physiology of tigers and considers what are absolutely necessary elements of their physical makeup. Even when she places a tiger in different habitats, her sight is aimed at the general condition of tigers and their needs in general.
However, things become even stranger when you start to consider how we think about mathematical objects. Consider the case of geometric figures. A triangle appears to be rather simple for most of us to think about. You can draw a triangle on a piece of paper, each side having a certain thickness and length. However when you think about this in geometry class, the triangle’s edges have no real thickness. Neither a point nor a line has a thickness for the mathematician. Such a thickness only exists on our paper, which represents the point or line. Consider also a line drawn on a piece of graph paper. Technically, there are an infinite number of points in the line. Indeed, even between 4.5 and 4.6, there are an infinite number of numbers—for example 4.55 is between them, then 4.555 between 4.55 and 4.6, and 4.5555 between 4.555 and 4.6, et cetera. In all of these cases, the mathematical reality takes on a very peculiar character when you consider it in the abstract. However, the concrete triangle remains very tangible and ordinary. Likewise, 4.6 and 4.5 inches still have 0.1 inches between them. Nevertheless, in the abstract, mathematical realities are quite strange, even stranger then the idea of “a tiger in general.”
What are the two things being contrasted in the first paragraph?
The first paragraph is focusing on the strange way that a scientist can consider "tigers in general." She is not so much concerned with any particular tiger as much as she is with the general "makeup" of tigers. These two ways of looking at the matter are the most directly contrasted point in this paragraph.
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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.
One of the main differences between an ostrich and a rail, according to the passage, is __________.
Ostriches and rails are discussed in the first paragraph. The author says that “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.” The passage then goes on to detail how rails have thin bodies that allow them to dart through the grass. This means that the correct answer is “ostriches run over open terrain whereas rails run through thick grass.”
The passage is describing the rail, a type of bird, and not using the word “rail” to describe part of a train track or a barrier on an elevated area, so “ostriches are living things whereas rails are inanimate objects” cannot be correct. Ostriches are never said to be smaller than rails or predators, so neither “ostriches are smaller than rails” nor “ostriches use their running abilities to catch prey, whereas rails use their running abilities to avoid predators” can be correct. Finally, rails are said to live in areas containing and have adapted to “thickly-growing vegetation” and ostriches are said to have developed a different adaptation suited to “open country,” so “ostriches live in grassy areas whereas rails live in the desert” cannot be correct either.
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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.
How does the second paragraph relate to the first paragraph?
Examining the two paragraphs, one can find that the first one talks about ostriches and rails, two types of flightless birds that adapted in specific ways to be good at fleeing predators. The second paragraph tells the story of the dodo, a flightless bird that did not have time to develop such adaptations. From here, we can pick out the correct answer: “The first paragraph describes flightless birds that learned to defend themselves from predators by fleeing them; the second paragraph describes a flightless bird that did not adapt in this way.”
As for the other answer choices, nothing in the passage discusses people eating birds, so we can ignore the answer choice “The first paragraph describes birds people eat; the second describes birds people do not eat.” The answer choice “The first paragraph describes a type of flightless birds that has gone extinct; the second describes species of flightless birds that are still living” would be correct if it flipped around the paragraphs to which it refers, but as it is written, it is incorrect. The passage doesn’t say anything about the predators of flightless birds in the first paragraph or the prey of flightless birds in either paragraph, so “The first paragraph discusses predators of flightless birds, the second describes prey of flightless birds” cannot be correct, and since the first paragraph does not provide a personal anecdote, “The first paragraph provides a personal anecdote while the second paragraph provides historical information” cannot be correct either.
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Adapted from "Recent Views as to Direct Action of Light on the Colors of Flowers and Fruits" in Tropical Nature, and Other Essays by Alfred Russel Wallace (1878)
The theory that the brilliant colors of flowers and fruits is due to the direct action of light has been supported by a recent writer by examples taken from the arctic instead of from the tropical flora. In the arctic regions, vegetation is excessively rapid during the short summer, and this is held to be due to the continuous action of light throughout the long summer days. “The further we advance towards the north, the more the leaves of plants increase in size as if to absorb a greater proportion of the solar rays. M. Grisebach says that during a journey in Norway he observed that the majority of deciduous trees had already, at the 60th degree of latitude, larger leaves than in Germany, while M. Ch. Martins has made a similar observation as regards the leguminous plants cultivated in Lapland.” The same writer goes on to say that all the seeds of cultivated plants acquire a deeper color the further north they are grown, white haricots becoming brown or black, and white wheat becoming brown, while the green color of all vegetation becomes more intense. The flowers also are similarly changed: those which are white or yellow in central Europe becoming red or orange in Norway. This is what occurs in the Alpine flora, and the cause is said to be the same in both—the greater intensity of the sunlight. In the one the light is more persistent, in the other more intense because it traverses a less thickness of atmosphere.
Admitting the facts as above stated to be in themselves correct, they do not by any means establish the theory founded on them; and it is curious that Grisebach, who has been quoted by this writer for the fact of the increased size of the foliage, gives a totally different explanation of the more vivid colors of Arctic flowers. He says, “We see flowers become larger and more richly colored in proportion as, by the increasing length of winter, insects become rarer, and their cooperation in the act of fecundation is exposed to more uncertain chances.” (Vegetation du Globe, col. i. p. 61—French translation.) This is the theory here adopted to explain the colors of Alpine plants, and we believe there are many facts that will show it to be the preferable one. The statement that the white and yellow flowers of temperate Europe become red or golden in the Arctic regions must we think be incorrect. By roughly tabulating the colors of the plants given by Sir Joseph Hooker as permanently Arctic, we find among fifty species with more or less conspicuous flowers, twenty-five white, twelve yellow, eight purple or blue, three lilac, and two red or pink; showing a very similar proportion of white and yellow flowers to what obtains further south.
In this passage, the author __________.
Answering this question requires you to read closely, as many theories are mentioned throughout the passage and keeping track of them can be quite challenging. In the first paragraph, the writer quotes a "recent writer," who then quotes evidence in the form of observations by M. Grisebach and M. Ch. Martins. In the second paragraph, the writer says that he agrees with the evidence of the "recent writer" (in other words, Grisebach and Martins), but not with the theory the "recent writer" has come up with to explain that evidence. So, the author disagrees with the "recent writer," but agrees with Grisebach, because the author goes on to quote Grisebach's own theory, with which the author agrees.
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"Darwin and His Influence" by Joseph Ritchie (2014)
In this passage, “selection” refers to traits that are selected for and passed on to later generations, and “species” refers to organisms that share a common ancestor and can produce viable offspring with one another.
Early in the nineteenth century, scientists sought to understand the differences in the earth’s flora and fauna from their archeological ancestors. The prevailing view at the time was that the differences between current and previous species were unremarkable deviations from their Platonic ideal forms. This theory hinged upon the ideals of the religious-based “created kinds” theory, which state that individuals of today are products of the organisms that were present at the earth’s creation, the result of an intelligent designer. Furthermore, these individuals believed that the differences between organisms could be explained by unseen geological and astrological forces acting on organisms slowly, throughout time. Other scientists also believed that individuals had the ability to change within their lifetimes and pass on traits to their offspring efficiently and quickly through a single generation.
Charles Darwin and other biologists, such as Alfred Wallace, were not greatly influenced by these views and hypotheses. Their propositions stated that species evolve over many generations, due to the selective pressures of their given environments. This evolution could result in the generation of divergent traits, as well as speciation and separation from the original ancestral species. The concept that organisms were not finite or present since creation was very controversial to the scientists of the period. Some saw such an idea as unsupportable, while others perceived it as heretical and fanatical.
Darwin set out to find support for his theory through his work, On the Origins of Species by Means of Natural Selection. He was influenced by archeological discoveries of species, which appeared to have vastly different physiological appearances from present-day organisms. Darwin decided to sail around the world on a Royal Navy ship named the H.M.S. Beagle. During his travels, he was taken to the Pacific islands of the Galapagos archipelago. The volcanic islands followed a patterned distribution on either side of the Equator. The landscapes of each island varied, with different observable flora and fauna. Through scientific observations, Darwin noticed subtle variations of finches on different islands. Some finches had large hard beaks, while others had slender beaks. Beaks were differentiated from island to island. After careful study, Darwin noticed that the beaks seemed to match the food source on each island. The large beaks were specialized for breaking open hard-shelled nuts, while the slender beaks were specialized for eating certain fruits that were abundant. Darwin hypothesized that an ancestral species of finch landed on the islands, and that over generations they became adapted to the locally abundant food sources.
Darwin compiled multiple instances of natural selection and incorporated discoveries made by archeologists and physiologists. He surmised that species evolve over time due to the selective pressures of their respective habitats. These events occur slowly over many generations. Each species selects for advantageous traits among its members. Over time, traits selected as advantageous by environmental pressures and stressors become commonplace in the species. This niche-forming process specializes species by rewarding those with traits most suitable for reproductive success. These traits may progress into speciation of the original species, which results in the eventual development of an entirely new species. Darwin’s theory was met with opposition at the time of its publication, and the theory of evolution remains a controversial topic in several arenas of debate.
The main difference between the "created kinds" theory and natural selection is represented by which of the following statements?
The "created kinds" theory suggests a finite number of species on earth while natural selection assumes species evolve.
This is the correct answer because it represents the main differences of the theories. Natural selection suggests that species evolve, change, and divert from themselves. This means that there is an infinite number of possible divergences not a finite amount as suggested by the "created kinds" model. No evidence in the passage suggests that either theory is correct, butter supported, religious based, or the foundation of Darwin's theory.
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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 does the author contrast in this passage?
Nowhere in the passage is the feeding of hummingbirds by humans mentioned, so “The results of feeding a hummingbird insects and the results of feeding a hummingbird flower nectar” cannot be correct. While a hummingbird with a long tail, the Polytmus, is mentioned, it is not contrasted with any short-tailed hummingbirds. The author appears to agree with Mr. Gosse’s opinion about what hummingbirds eat, so “The author’s opinion about what hummingbirds eat and Mr. Gosse’s opinion about what hummingbirds eat” cannot be correct either. This leaves us with “Hummingbirds that eat flower nectar and hummingbirds that eat insects” and “the beliefs of historical scientists and the beliefs of scientists of the author’s time.” While the passage is concerned with what hummingbirds eat, it doesn’t suggest that some types of hummingbirds eat only nectar and others eat only insects. Hummingbirds are considered as an entire group; they’re never divided into “hummingbirds that eat insects” and “hummingbirds that eat flower nectar.” This leaves us with one answer choice, the correct one: “The beliefs of historical scientists and the beliefs of scientists of the author’s time.” These beliefs are contrasted in the paragraph’s second sentence: “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.”
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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.”
What do Azara, Bullock, and Waterton have in common?
Azara, Bullock, and Waterton are all mentioned near the beginning of the passage. The author writes, “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 then mentioned the following:
(1) "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."
(2) "Bullock, in Mexico, declares that he saw them catch small butterflies, and that he found many kinds of insects in their stomachs."
(3) **"**Waterton made a similar statement."
The author is suggesting that Azara, Bullock, and Waterton fall into the group of “every close observer of their habits.” The three also make statements about hummingbirds. From this, we can narrow down our answers to three choices: that Azara, Bullock, and Waterton are critics of the author, scientists who think hummingbirds eat insects, or scientists who think hummingbirds eat flower nectar. Nowhere in the passage do the statements made by these writers appear to contradict the author’s opinion, so we can discard the idea that Azara, Bullock, and Waterton are critics of the author. So, are they saying that hummingbirds eat flower nectar or insects? They author says that early observers of hummingbirds thought that they eat flower nectar, but that more recent scientists—like the three quoted—think that they eat insects. The statements made by each also relate to hummingbirds eating insects, so the correct answer is “They are all scientists who think hummingbirds eat insects.”
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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?
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.”
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