GMAT Verbal : Extrapolating from the Text in Natural Science Passages
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Example Question #3 : Comparing And Contrasting Ideas In And Aspects Of Natural Science Passages
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?
They are all scientists who think hummingbirds eat insects.
They are all types of birds that eat insects.
They are all types of hummingbirds.
They are all critics of the writer and disagree with his theory.
They are all scientists who think hummingbirds eat flower nectar.
They are all scientists who think hummingbirds eat insects.
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.”
Example Question #2 : Recognizing The Main Idea In Narrative Science Passages
"Darwinism's Effect on Science" by Matthew Minerd (2014)
For much of the history of human thought, the sciences have studied subjects that seemed to be eternal and unchanging. Even the basic laws of the Nile’s flooding were investigated in the hopes of finding never-altering laws. Similarly, the scientific investigations of the ancient Near East and Greece into the regular laws of the stars ultimately looked for constant patterns. This overall pattern of scientific reasoning has left deep marks on the minds of almost all thinkers and found its apotheosis in modern physics. From the time of the early renaissance to the nineteenth century, physics represented the ultimate expression of scientific investigation for almost all thinkers. Its static laws appeared to be the unchanging principles of all motion and life on earth. By the nineteenth century, it had appeared that only a few details had to be “cleared up” before all science was basically known.
In many ways, this situation changed dramatically with the arrival of Darwinism. It would change even more dramatically in early twentieth-century physics as well. Darwin’s theories of evolution challenged many aspects of the “static” worldview. Even those who did not believe that a divine being created an unchanging world were shaken by the new vistas opened up to science by his studies. It had been a long-accepted inheritance of Western culture to believe that the species of living organisms were unchanging in nature. Though there might be many different kinds of creatures, the kinds themselves were not believed to change. The thesis of a universal morphing of types shattered this cosmology, replacing the old world-view with a totally new one. Among the things that had to change in light of Darwin’s work was the very view of science held by most people.
Consider the underlined sentence. What was the new “cosmology” that arose after Darwin’s day?
None of the other answers
The view of the world as a changing reality with its own historical nature.
The belief that history was an important but secondary aspect of scientific studies.
A completely areligious outlook on life.
The view of the world as an unchanging whole to be investigated by science.
The view of the world as a changing reality with its own historical nature.
Throughout the second paragraph, the passage discusses again the "static" nature of the former scientific outlook. The new worldview was quite different. You can guess at the meaning of "cosmology" by noticing the contrast between it and "universal morphing of types." A "cosmology" is a particular outlook on the world or reality as a whole. The passage implies that Darwin's work made it necessary to see the world as a changing whole with its own history.
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