SAT Critical Reading : Considering Analogous Concepts in Natural Science Passages

Study concepts, example questions & explanations for SAT Critical Reading

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Example Questions

Example Question #1 : Extrapolating From The Text In Natural Science Passages

Adapted from "Taking a Second Look: An Analysis of Genetic Markers in Species Relatedness" by Joseph Ritchie (2014)

Phylogenetics is the study of genetic composition in various species and is used by evolutionary biologists to investigate similarities in the molecular sequences of proteins in varying organisms. The amino acid sequences that build proteins are used to construct mathmatical matrices that aid in determining evolutionary ties through the investigation of percentage similarities. The study of these matrices helps to expose evolutionary relationships between species that may not have the same overt characteristics.

Species adapt and evolve based on the pressures that exist in their environment. Climate, food source, and habitat availability are only a few factors that act on species adaptation. These stressors can alter the physical characteristics of organisms. This divergence in evolution has made it difficult to determine the interrelatedness of organisms by analyzing their physical characteristics alone.

For instance, looking only at physical characteristics, the ghost bat resembles a pigeon more than a spider monkey; however, phylogenetics has found that the amino acid sequences that construct the beta hemoglobin molecules of bats are twenty percent more similar to those of mammalian primates than those of birds. This helps reject the assumption that common physical characteristics between species are all that is needed to determine relatedness. 

The differences produced by divergent evolution observed in the forest-dwelling, arboreal spider monkey and the nocturnal, airborne ghost bat can be reconciled through homology. Homologous characteristics are anatomical traits that are similar in two or more different species. For instance, the bone structure of a spider monkey’s wrist and fingers greatly resembles that of a bat’s wing or even a whale’s fin. These similarities are reinforced by phylogenetic evidence that supports the idea that physically dissimilar species can be evolutionarily related through anatomical and genetic similarities.

A scientist studied the relatedness of several reptilian species solely by investigating fossil evidence and has concluded that physical characteristics alone are enough to determine species relatedness. Would this scientist agree with the claims made by phylogenetic research?

Possible Answers:

Yes, because phylogenetics is second to physical comparisons and thus supports the archaeologist's position.

None of the other choices are correct.

No, because phylogenetics assumes that physical traits and characteristics are not the only objective and reliable markers in the study of species relatedness.

No, because phylogenetics is an unreliable and new technique that has yet to prove itself in major scientific arenas.

Yes, because a great deal of research is based on physical comparisons.

Correct answer:

No, because phylogenetics assumes that physical traits and characteristics are not the only objective and reliable markers in the study of species relatedness.

Explanation:

The scientist studied relatedness based on the fossil record of physical traits. He would not agree with the notion that phylogenetics may better explain relatedness via genetic factors. The rest of the choices are incorrect because they are not supported by the passage.

Example Question #2 : Extrapolating From The Text In Natural Science Passages

Adapted from "Taking a Second Look: An Analysis of Genetic Markers in Species Relatedness" by Joseph Ritchie (2014)

Phylogenetics is the study of genetic composition in various species and is used by evolutionary biologists to investigate similarities in the molecular sequences of proteins in varying organisms. The amino acid sequences that build proteins are used to construct mathmatical matrices that aid in determining evolutionary ties through the investigation of percentage similarities. The study of these matrices helps to expose evolutionary relationships between species that may not have the same overt characteristics.

Species adapt and evolve based on the pressures that exist in their environment. Climate, food source, and habitat availability are only a few factors that act on species adaptation. These stressors can alter the physical characteristics of organisms. This divergence in evolution has made it difficult to determine the interrelatedness of organisms by analyzing their physical characteristics alone.

For instance, looking only at physical characteristics, the ghost bat resembles a pigeon more than a spider monkey; however, phylogenetics has found that the amino acid sequences that construct the beta hemoglobin molecules of bats are twenty percent more similar to those of mammalian primates than those of birds. This helps reject the assumption that common physical characteristics between species are all that is needed to determine relatedness. 

The differences produced by divergent evolution observed in the forest-dwelling, arboreal spider monkey and the nocturnal, airborne ghost bat can be reconciled through homology. Homologous characteristics are anatomical traits that are similar in two or more different species. For instance, the bone structure of a spider monkey’s wrist and fingers greatly resembles that of a bat’s wing or even a whale’s fin. These similarities are reinforced by phylogenetic evidence that supports the idea that physically dissimilar species can be evolutionarily related through anatomical and genetic similarities.

According to the passage, the hemoglobin structure of a bat is most similar to which of the following animals?

Possible Answers:

Hummingbird

Spider monkey

Pigeon

Owl

Eagle

Correct answer:

Spider monkey

Explanation:

The spider monkey is the only mammalian species listed in the choices. The other choices are birds, which the passage states are less similar to bats than mammals.

Example Question #26 : Ideas In 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.

Which of the following provides an example of the main idea asserted in the first paragraph?

Possible Answers:

The interest in science only arises once agriculture reaches a certain point of fixity.

None of the other answers

Religion constantly wanes with the rise of science.

The fluctuation of coloration within a species is rather minimal.

The Pythagorean theorem is based upon the constant relationship of the sides of a right triangle to its hypotenuse.

Correct answer:

The Pythagorean theorem is based upon the constant relationship of the sides of a right triangle to its hypotenuse.

Explanation:

The first paragraph discusses the role of necessary connections and unvarying rules in scientific thinking, particularly the type of thinking that has played a prominent role in Western thought for many centuries. The example of the Pythagorean theorem is a good example of this.  Even if you do not know this mathematical equation, you can tell that this is the correct answer by the words "constant relationship."

Example Question #1 : Comparing And Contrasting Ideas In Natural Science Passages

"Cacti" by Ami Dave (2013)

Cacti are plants suited to the desert, and we must always keep this factor in mind when growing ornamental cacti in our gardens, for it helps us provide cacti with conditions that allow them to survive and thrive. For example, a cactus should never be watered over its body, as it will start to rot. This is because it is covered with a waxy coating which prevents water loss through evaporation. When one waters the cactus over its body, the waxy coating is washed away and the plant begins to rot. The amount of water that one must supply to the cactus is very much dependent upon the season and upon the climate of the place. During the summer season one should water cacti every four days, whereas in the rainy season, once every fifteen days is quite enough.

Cacti need a minimum of two and a half hours of sunlight per day; however, they should not be kept in the sun all day because they may wrinkle when exposed to too much bright sunlight. Unlike other plants, cacti produce carbon dioxide during the day and oxygen during the night, so they are ideal plants to be kept in bedrooms to freshen up the air at night.

If a cactus is to thrive and prosper, the size of the pot in which it is grown needs to be monitored carefully. The pot should always be a little smaller than the plant itself because it is only when the plant has to struggle to survive that it will thrive. If the pot is too spacious and the plant does not need to struggle, chances are that the cactus will die. Similarly, if a cactus shows no signs of growth, stop watering it. Watering should be resumed only when the plant begins to grow again.

The substrata of a cactus pot is ideally composed of pieces of broken bricks at the bottom, followed by a layer of charcoal above the bricks, and then coarse sand and pebbles above the charcoal. Leaf mould is the best manure.

Grafting cacti is very simple. A very small piece of the cactus plant should be stuck with tape to the plant that needs grafting. The smaller the piece, the easier it is to graft. To reproduce cacti, one has to simply cut off a piece of the cactus, allow it to dry for a few days, and then place it over the cacti substrate. It will automatically develop roots.

It is very easy to differentiate between cacti and other plants that look like cacti. All cacti have fine hair at the base of each thorn. The so-called “thorns” are in fact highly modified leaves which prevent loss of water through transpiration. If one ever gets pricked by cacti thorns, one should take tape, place it over the area where the thorns have penetrated the skin, and then peel it off. All of the thorns will get stuck to the tape and will be removed.

The development of a new cactus from a graft is similar to what other biological phenomenon?

Possible Answers:

A lizard that regrows its tail

A cut that successfully heals

The birth of a genetically unique organism from an egg

An unsuccessful kidney transplant

A nematode worm that develops into two separate organisms when cut in half

Correct answer:

A nematode worm that develops into two separate organisms when cut in half

Explanation:

The passage discusses how grafting is a relatively simple procedure, and all that one must do is cut off a piece of the cactus and place it in an environment that supports its growth: the new cactus will develop roots. This is most similar to when a worm develops into a new organism when part of it is cut off. A lizard regrowing its tail is not similar to a graft, since the original organism simply regains the part that it lost. In the same vein, a cut that heals also involves an organism healing itself, not splitting apart to form a new organism. Birth from an egg or a failed organ transplant are not similar to the effects of a cactus graft.

Example Question #241 : Natural Science Passages

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

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

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

The kiwi is a bird that lives in New Zealand. New Zealand has no native ground-dwelling predatory animals. The stoat, a ground-dwelling carnivorous mammal, was introduced to New Zealand. Based on the passage, what can you predict happened?

Possible Answers:

the stoats could not support themselves in the new environment and died off

the kiwis quickly learned to defend themselves against stoats

None of the other answers

the kiwi population rose

the kiwi population drastically decreased

Correct answer:

the kiwi population drastically decreased

Explanation:

The situation presented in this question lines up precisely with the dodo’s story in the passage. The kiwi, like the dodo, would thus be unable to defend itself from introduced predators, since like on Mauritius, New Zealand has no native ground-dwelling predators. We can therefore predict that in this situation, the kiwi population would decrease drastically, if not go extinct, so “the kiwi population drastically decreased” is the correct answer. (In fact, the kiwi and stoat situation actually happened in New Zealand. While the kiwi remains a living species, New Zealand has had to work very hard to protect it from stoats.)

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