ISEE Lower Level Reading : Identifying and Analyzing Main Idea and Theme in Science Passages

Study concepts, example questions & explanations for ISEE Lower Level Reading

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Example Question #1 : Identifying And Analyzing Main Idea And Theme In Science Passages

"The Multiple Sides of Computer Science" by Matthew Minerd (2014)

It often takes some time for a new discipline to become recognized as an independent science. An excellent example of this is computer science. In many ways, this science still is a hodgepodge of several different sciences, each one having its own distinct character. For example, some computer scientists are almost indistinguishable from mathematicians. Many of the most difficult topics in pattern recognition and data communications require intensive mathematics in order to provide software solutions. Years of training in the appropriate disciplines are necessary before the computer scientist can even begin to work as a programmer in such areas. In contrast to those computer scientists who work with complex mathematics, many computer scientists work on areas of hardware development that are similar to disciplines like electrical engineering and physics.

However, computer science has its own particular problems regarding the unity of its subject matter. There are many practical applications for computing work; therefore, many computer scientists focus on learning a large set of skills in programming languages, development environments, and even information technology. All of these disciplines have a certain practical coloration that is quite distinct from the theoretical concepts used in other parts of the field. Nevertheless, these practical topics add to the broad range of topics covered by most academic programs that claim to focus on “computer science.” It can only be hoped that these disciplines will increase in orderliness in the coming decades.

What is the main point introduced in the second paragraph?

Possible Answers:

The applied nature of computer science creates a unique set of problems regarding the discipline's unity

Computer science only becomes "real" when it is applied to the real world

None of these

Computer science is a very practical science for most topics

Many programmers are mere technicians, not real computer scientists

Correct answer:

The applied nature of computer science creates a unique set of problems regarding the discipline's unity

Explanation:

The second paragraph focuses on the fact that computer science has a host of practical applications. In particular, these practical applications make it even more difficult to see the focus of computer science studies. Therefore, they tend to hide the unity of the topic even more (that is, even beyond the more "academic" issues discussed in the first paragraph).

Example Question #1 : Identifying And Analyzing Main Idea And Theme In Science Passages

"The Multiple Sides of Computer Science" by Matthew Minerd (2014)

It often takes some time for a new discipline to become recognized as an independent science. An excellent example of this is computer science. In many ways, this science still is a hodgepodge of several different sciences, each one having its own distinct character. For example, some computer scientists are almost indistinguishable from mathematicians. Many of the most difficult topics in pattern recognition and data communications require intensive mathematics in order to provide software solutions. Years of training in the appropriate disciplines are necessary before the computer scientist can even begin to work as a programmer in such areas. In contrast to those computer scientists who work with complex mathematics, many computer scientists work on areas of hardware development that are similar to disciplines like electrical engineering and physics.

However, computer science has its own particular problems regarding the unity of its subject matter. There are many practical applications for computing work; therefore, many computer scientists focus on learning a large set of skills in programming languages, development environments, and even information technology. All of these disciplines have a certain practical coloration that is quite distinct from the theoretical concepts used in other parts of the field. Nevertheless, these practical topics add to the broad range of topics covered by most academic programs that claim to focus on “computer science.” It can only be hoped that these disciplines will increase in orderliness in the coming decades.

What will be the effect of increased orderliness in computer science studies?

Possible Answers:

It will help to overcome biases against practical applications of computer science

It will be easier to understand the distinct topic studied in computer science

It will make scheduling much easier for most students

It will allow for greater progress in experimentation

It will set to rest the debates about computer science's importance

Correct answer:

It will be easier to understand the distinct topic studied in computer science

Explanation:

The main focus of this whole passage is the fact that it is hard to figure out the single thing studied by computer science. It has many branches, all of which seem to be rather different and unrelated (or at least not very related). With increased orderliness, we can assume that it will become clearer just what is the special topic studied in computer science—as opposed to mathematics, physics, or information technology.

Example Question #1 : Science Passages

"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.”

Which of the following would strengthen the ending of the first paragraph?

Possible Answers:

"Of course, she becomes quite attached to all of the animals in her care."

None of the other answers

"The details of any particular tiger’s life are interesting only as a means to this end."

"Each individual tiger has its own unique characteristics and abilities."

"Every animal is carefully tested as a potential test subject."

Correct answer:

"The details of any particular tiger’s life are interesting only as a means to this end."

Explanation:

As written, the last sentence in the first paragraph states that the scientist is interested in figuring out what "tigers in general" are like. Therefore, any particular tiger is not as important as this general nature of tigers (how they generally can live, thrive, etc).  The best way to end this paragraph is by reiterating this point, which is what the correct answer does.

Example Question #1 : Identifying And Analyzing Main Idea And Theme In Science Passages

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.

Which of the following best expresses the main idea of the passage?

Possible Answers:

Increased defense is the only reason for an animal to change its fur color.

The Scottish hare changes its fur color.

Certain animals change their fur color to be better predators or better at hiding.

All animals that live in a changing environment change color.

Animals like the stoat, the weasel, and the Irish hare are better adapted to changing environments than to unchanging ones.

Correct answer:

Certain animals change their fur color to be better predators or better at hiding.

Explanation:

When answering questions about the main idea of a passage, it’s important to pick out an answer choice to which each paragraph relates, but one that isn’t too broad. Some of the answer choices to this question are too specific: “The Scottish hare changes its fur color” is, and we can tell because the first paragraph doesn’t say anything about the Scottish hare, and the third paragraph only mentions it in its last line. “Increased defense is the only reason for an animal to change its fur color” should get your attention due to its use of the word “only”—did we hear anything in the passage about color-changing adaptations being used “only” for defense? No, we heard the opposite, in the passage’s last line: “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.” The language may be a bit dense here, but what the passage is saying is that the hare uses its color-changing adaptation for defense, but stoats and weasels use it for being better predators and sneaking up on their prey—definitely not a defensive use. Similarly, “All animals that live in a changing environment change color” is making a strong statement due to its use of the word “all.” The passage gives us a few examples of animals that change that live in a changing environment and change their color, but this isn’t enough for us to assume that all animals that live in changing environments act this way. 

Example Question #2 : Identifying And Analyzing Main Idea And Theme In Science Passages

Adapted from Cassell’s Natural History by Francis Martin Duncan (1913)

The penguins are a group of birds inhabiting the southern ocean, for the most part passing their lives in the icy waters of the Antarctic seas. Like the ratitae, penguins have lost the power of flight, but the wings are modified into swimming organs and the birds lead an aquatic existence and are scarcely seen on land except in the breeding season. They are curious-looking creatures that appear to have no legs, as the limbs are encased in the skin of the body and the large flat feet are set so far back that the birds waddle along on land in an upright position in a very ridiculous manner, carrying their long narrow flippers held out as if they were arms. When swimming, penguins use their wings as paddles while the feet are used for steering.

Penguins are usually gregarious—in the sea, they swim together in schools, and on land, assemble in great numbers in their rookeries. They are very methodical in their ways, and on leaving the water, the birds always follow well-defined tracks leading to the rookeries, marching with much solemnity one behind the other in soldierly order. 

The largest species of penguins are the king penguin and the emperor penguin, the former being found in Kerguelen Land, the Falklands, and other southern islands, and the latter in Victoria Land and on the pack ice of the Antarctic seas. As they are unaccustomed from the isolation of their haunts to being hunted and persecuted by man, emperor penguins are remarkably fearless, and Antarctic explorers invading their territory have found themselves objects of curiosity rather than fear to the strange birds who followed them about as if they were much astonished at their appearance. 

The emperor penguin lays but a single egg and breeds during the intense cold and darkness of the Antarctic winter. To prevent contact with the frozen snow, the bird places its egg upon its flat webbed feet and crouches down upon it so that it is well covered with the feathers. In spite of this precaution, many eggs do not hatch and the mortality amongst the young chicks is very great.

Which of the following best describes this passage?

Possible Answers:

A general description of penguins

A descriptive passage detailing the appearance of penguins

A description of different types of birds

The author’s personal story of visiting Antarctica and seeing penguins for the first time

An informational passage about how emperor penguins care for their eggs

Correct answer:

A general description of penguins

Explanation:

When answering questions about a passage’s main idea or purpose, it is important not to pick the first answer that mentions something the passage talks about. To accurately represent the main idea of a passage, a statement has to relate to each of a passage’s paragraphs while not being too broad. For instance, “A description of different types of birds” is too broad to be the correct answer here, since the passage only talks about penguins. On the other hand, “An informational passage about how emperor penguins care for their eggs” cannot be correct because this is only discussed in the passage’s last paragraph, and “A descriptive passage detailing the appearance of penguins” cannot be correct because only the first paragraph in the passage describes the appearance of penguins. The passage can’t be best described as “The author’s personal story of visiting Antarctica and seeing penguins for the first time,” since this informational passage is presented in the third person perspective (it doesn’t use the “I” perspective) and doesn’t tell us anything that specifically happened to a given person. This leaves us with the correct answer: the passage is best described as “a general description of penguins.” Each of the passage’s paragraphs can be accurately described by this statement, and it isn’t too broad.

Example Question #152 : Prose Passages

Adapted from "Sea-slugs and Cuttlefish" by Charles Darwin in A Book of Natural History (1902, ed. David Starr Jordan)

I was much interested, on several occasions, by watching the habits of a cuttlefish. Although common in the pools of water left by the retiring tide, these animals were not easily caught. By means of their long arms and suckers, they could drag their bodies into very narrow crevices; and when thus fixed, it required great force to remove them. At other times they darted, with the rapidity of an arrow, from one side of the pool to the other, at the same instant discoloring the water with a dark chestnut-brown ink. These animals also escape detection by a very extraordinary, chameleon-like power of changing their color. They appear to vary their tints according to the nature of the ground over which they pass: when in deep water, their general shade was brownish-purple, but when placed on the land, or in shallow water, this dark tint changed into one of a yellowish green.

This cuttlefish displayed its chameleon-like power both during the act of swimming and whilst remaining stationary at the bottom. I was amused by the various arts to escape detection used by one individual, which seemed fully aware that I was watching it. Remaining for a time motionless, it would then stealthily advance an inch or two, like a cat after a mouse; sometimes changing its color, it proceeded, till having gained a deeper part, it darted away, leaving a dusky train of ink to hide the hole into which it had crawled.

The main idea of this passage is that __________.

Possible Answers:

Cuttlefish are very common in the rock pools near where the author lives.

The author is very interested in the habits of cuttlefish.

Cuttlefish are very small and agile creatures.

The author has never successfully caught a cuttlefish.

Cuttlefish have many different abilities that help them to avoid capture.

Correct answer:

Cuttlefish have many different abilities that help them to avoid capture.

Explanation:

The main idea of this passage is that cuttlefish are very difficult to catch because they have many different skills that allow them to avoid capture. The author talks about their “chameleon-like power of changing their color,” their “long arms and suckers” with which “they could drag their bodies into very narrow crevices,” and their ability to dart “with the rapidity of an arrow, from one side of the pool to the other, at the same instant discoloring the water with a dark chestnut-brown ink.” The main thesis of the text is probably “Although common in the pools of water left by the retiring tide, these animals were not easily caught.” The other answer choices are common features of this text, but not the main idea of the passage.

Example Question #3 : Science Passages

Adapted from "Bats" by W. S. Dallas in A Book of Natural History (1902, ed. David Starr Jordan)

Like the owls, with which they share the dominion of the evening air, the bats have a perfectly noiseless flight; their activity is chiefly during the twilight, although some species are later, and in fact seem to keep up throughout the whole night. As they rest during the day, concealed usually in the most inaccessible places they can find, and are seen only upon the wing, their power of flight is their most striking peculiarity in the popular mind, and it is perhaps no great wonder that by many people, both in ancient and modern times, they have been regarded as birds. Nevertheless, their hairy bodies and leathery wings are so unlike anything that we ordinarily understand as pertaining to a bird, that opinion was apparently always divided, as to the true nature of these creatures—“a mouse with wings,” as Goldsmith called it once, according to James Boswell, is certainly a curious animal, and very difficult to classify so long as the would-be systematist has no particularly definite ideas to guide him. The likeness of the bat to a winged mouse has made itself felt in the name given to the creature in many languages, such as the “chauvesouris” of the French and the “flitter-mouse” of some parts of England, the latter being reproduced almost literally in German, Dutch, and Swedish, while the Danes called the bat a “flogenmues,” which has about the same meaning.

Throughout this passage the author primarily highlights the __________ nature of bats.

Possible Answers:

calculating

mysterious

nocturnal

abrasive

unruly

Correct answer:

mysterious

Explanation:

At various parts of this passage, the author highlights the “mysterious" nature of bats. Although he does briefly mention the “nocturnal” (sleeping during the day and being awake at night) nature of bats, as when he says “their activity is chiefly during the twilight, although some species are later, and in fact seem to keep up throughout the whole night," this is not the primary focus. Examples of the author highlight the “mysterious” nature of bats can be seen when he says, “As they rest during the day, concealed usually in the most inaccessible places they can find,“ and “their power of flight is their most striking peculiarity in the popular mind,“ and “Nevertheless, their hairy bodies and leathery wings are so unlike anything that we ordinarily understand as pertaining to a bird, that opinion was apparently always divided, as to the true nature of these creatures.”

Example Question #2 : Identifying And Analyzing Main Idea And Theme In Science Passages

Adapted from Chatterbox Stories of Natural History by R. Worthington (1880)

I would now like to talk briefly about the beaver. This industrious animal is generally found in Canada and the northern portions of the United States, where it makes its home on the banks of the rivers and lakes. Here they assemble in hundreds to assist each other in the construction of their dams, and in the building of their houses, which are put together with a considerable amount of engineering skill. The materials used in building the dams are wood, stones, and mud, which they collect themselves for that purpose, and after finishing the dam, or winter storehouse, they collect their stores for the winter's use, and then make a connection with their houses in the banks. Their skins are valuable in making fine hats, and their flesh is much relished by the hunters. The beaver is an interesting animal in many respects, and the expression “busy as a beaver” is borne out by its habits.

The main point of this passage is to __________.

Possible Answers:

Explain where beavers come from

Describe the impact of beavers on humans

Describe the behavior of beavers

Argue in favor of eating beaver meat

Argue against beaver hunting

Correct answer:

Describe the behavior of beavers

Explanation:

The majority of this passage is given over to describing the hard-working nature and behavior of beavers. Although it is true that the author talks about the impact of beavers on the English language, to say that the main point of this passage is to describe the impact of beavers on humans would be ignoring the entirety of the rest of the passage that is entirely focused on describing how beavers go about their work.

Example Question #3 : Science Passages

Adapted from Chatterbox Stories of Natural History by R. Worthington (1880)

The guinea pig is a native of South America, and is remarkable for the beauty and variety of its colors and the neatness of its appearance. These little pets are very careful in keeping themselves and their offspring neat and tidy, and may be frequently seen smoothing and dressing their fur, somewhat in the manner of a cat. After having smoothed and dressed each other's fur, both turn their attention to their young, from whose coats they remove the smallest speck of dirt, at the same time trying to keep their hair smooth and unruffled. The guinea pig feeds on bread, grain, fruit, vegetables, tea leaves, and especially garden parsley, to which it is very partial. It generally gives birth to seven and eight young at a time, and they very soon are able to take care of themselves.

The main point of this passage is __________.

Possible Answers:

to describe what guinea pigs like to eat

to argue that guinea pigs make good pets

to explain where guinea pigs come from

to outline how guinea pigs care for their young

to provide a brief overview of guinea pigs

Correct answer:

to provide a brief overview of guinea pigs

Explanation:

There is no evidence to suggest the author is arguing anything in this passage, so we know this is not about whether or not guinea pigs make good pets. The correct answer choice is that the point of this passage is "to provide a brief overview of guinea pigs.” The author talks about what they like to eat, where they come from, how they care for their young, but each of these is part of the author’s attempts to briefly describe guinea pigs.

Example Question #3 : Identifying And Analyzing Main Idea And Theme In Science Passages

Adapted from "Birds’ Nests" by John Burroughs in A Book of Natural History (1902, ed. David Starr Jordan)

The rarest of all nests is that of the eagle, because the eagle is the rarest of all birds. Indeed, so seldom is the eagle seen, that its presence always seems accidental. It appears as if merely pausing on the way, while bound for some distant unknown region. One September, while a youth, I saw the ring-tailed eagle, an immense bird, the sight of which filled me with awe. It lingered about the hills for two days. Some young cattle, a two year-old colt, and half a dozen sheep were at pasture on a high ridge that led up to the mountain, and in plain view of the house. On the second day, this dusky monarch was seen flying about above them. Presently he began to hover over them, after the manner of a hawk watching for mice. He then with extended legs let himself slowly down upon them, actually grappling the backs of the young cattle, and frightening the creatures so that they rushed about the field in great consternation; and finally, as he grew bolder and more frequent in his descents, the whole herd broke over the fence, and came tearing down to the house “like mad.” It did not seem to be an assault with intent to kill, but was, perhaps, a stratagem resorted to in order to separate the herd and expose the lambs, which hugged the cattle very closely. When he occasionally alighted upon the oaks that stood near, the branch could be seen to sway and bend beneath him. Finally, as a rifleman started out in pursuit of him, he launched into the air, set his wings, and sailed away southward. A few years afterward, in January, another eagle passed through the same locality, alighting in a field near some dead animal, but tarried briefly.

Which of these excerpts best captures the main idea and purpose behind the author’s writing of this article?

Possible Answers:

“One September, while a youth, I saw the ring-tailed eagle, an immense bird, the sight of which filled me with awe.”

“Finally, as a rifleman started out in pursuit of him, he launched into the air, set his wings, and sailed away southward.”

“A few years afterward, in January, another eagle passed through the same locality, alighting in a field near some dead animal, but tarried briefly.”

“It did not seem to be an assault with intent to kill, but was, perhaps, a stratagem resorted to in order to separate the herd and expose the lambs, which hugged the cattle very closely.”

“Indeed, so seldom is the eagle seen, that its presence always seems accidental.”

Correct answer:

“Indeed, so seldom is the eagle seen, that its presence always seems accidental.”

Explanation:

The author’s primary purpose in writing this article is to illustrate how rarely seen an eagle is. He also wants to convey some sense that because eagles are so rare and seem to linger only for a short time that they seem somehow like they do not belong, as if they are accidentally there and ought to be elsewhere. This combined purpose is best expressed by “Indeed, so seldom is the eagle seen, that its presence always seems accidental.”

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