comprehension for sem

8/10/2019 Comprehension for Sem

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PASSAGE 1

In prehistoric times brachiopods were one of the most abundant and diverse forms of life on Earth: more than

30,000 species of this clamlike creature have boon cataloged from fossil records. Today brachiopods are not

as numerous, and existing species are not well studied, partly because neither the animals flashy inner tissue,

nor its shell has any commercial value. Moreover, in contrast to the greater diversity of the extinct species, the

approximately 300 known surviving species are relatively uniform in appearance. Many zoologists have

interpreted this as a sign that the animal has been unable to compete successfully with other marina organismsin the evolutionary struggle.

Several things, however, suggest that the conventional view needs revising. For example, the genus Lingula

has an unbroken fossil record extending over more than half a billion years to the present. Thus, if longevity is

any measure, brachiopods are the most successful organisms extant. Further, recent studies suggest that

diversity among species is a less important measure of evolutionary success than is the ability to withstand

environmental change, such as when a layer of clay replaces sand on the ocean bottom. The relatively greater

uniformity among the existing brachiopod species may offer greater protection from environmental change

and hence may reflect highly successful adaptive behavior.

The adaptive advantages of uniformity for brachiopods can be seen by considering specialization, a processthat occurs as a result of prolonged colonization of a uniform substrate. Those that can survive on many

surfaces are called generalists, while those that can survive on a limited range of substrates are called

specialists. One specialist species, for example, has valves weighted at the base, a characteristic that assures

that the organism is properly positioned for feeding in mud and similar substrates: other species secrets glue

allowing them to survive on the face of underwater cliffs. The fossil record demonstrates that most brachiopod

lineages have followed a trend toward increased specialization. However, during periods of environmental

instability, when a particular substrate to which a specialist species has adapted is no longer available, the

species quickly dies out. Generalists, on the other hand, are not dependent on a particular substrate, and are

thus less vulnerable to environmental change. One study of the fossil record revealed a mass extinction of

brachiopods following a change in sedimentation from chalk to clay. Of the 35 brachiopod species found inthe chalk, only 6 survived in the clay, all of them generalists.

As long as enough generalist species are maintained, and studies of arctic and subarctic seas suggest that

generalists are often dominant members of the marina communities there, it seams unlikely that the phylum is

close to extinction.

1. The second paragraph makes use of which of the following?

(A) Specific examples

(B) Analogy

(C) Metaphor(D) Quotation

(E) Exaggeration

2. In the passage, the author is primarily concerned with

(A) rejecting an earlier explanation for the longevity of certain brachiopod species

(B) reevaluating the implications of uniformity among existing brachiopod species

(C) describing the varieties of environmental change to which brachiopods are vulnerable

(D) reconciling opposing explanations for brachiopods lack of evolutionary success

(E) elaborating on the mechanisms responsible for the tendency among brachiopod species toward

specialization

3. It can be inferred from the passage that the decision to study an organism may sometimes be influenced by


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(A) its practical or commercial benefits to society

(B) the nature and prevalence of its fossilized remains

(C) the relative convenience of its geographical distribution

(D) its similarity to one or more better-known species

(E) the degree of its physiological complexity

4. Which of the following, if true, would most strengthen the authors claim that it seems unlikely that the

phylum is close to extinction?

(A) Generalist species now living in arctic waters give few if any indications of a tendency toward significant

future specialization.

(B) Zoologists have recently discovered that a common marine organism is a natural predator of brachiopods.

(C) It was recently discovered that certain brachiopod species are almost always concentrated near areas rich

in offshore oil deposits.

(D) The ratio of specialist to generalist species is slowly but steadily increasing.

(E) It is easier for a brachiopod. to survive a change in sedimentation than a change in water temperature.

5. Assuming that it exists, a brachiopod possessing which of the following features is most clearly NOT anexample of a specialist brachiopodspecies as that term is used by the author?

(A) A fleshy, adhesive stalk enabling attachment to a wide variety of surfaces

(B) A gland secreting glue that enables survival on the face of underwater cliffs

(C) Larval behavior that enhances survival on smooth, sandy sediments

(D) A shall structure providing easy mobility on fine, but not coarse, sand

(E) Anchoring spines that offer needed stability on soft mud

6. It can be inferred from the passage that many zoologists assume that a large diversity among species of a

given class of organisms typically leads to which of the following?

(A) Difficulty in classification

(B) A discontinuous fossil record

(C) A greater chance of survival over time

(D) Numerical abundance

(E) A longer life span

7. The author suggests that the scientists holding the conventional view make which of the following errors?

(A) They mistakenly emphasize survival rather than diversity.

(B) They misunderstand the causes of specialization.

(C) They misuse zoological terminology.

(D) They catalog fossilized remains improperly.

(E) They overlook an alternative criterion of evolutionary success

8. Information in the passage supports which of the following statements about brachiopods?

I. Few brachiopods living in prehistoric times were specialists.

II. A tendency toward specialization, though typical, is not inevitable.

III. Specialist species dominate in all but arctic and subarctic waters.

(A) I only

(B) II only(C) II and III only

(D) I and III only

(E) I. II. and III


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Answer:

1. A 2. B 3. A 4. A 5. A 6.C 7. E 8.B

PASSAGE 2

Most people can remember a phone number for up to thirty seconds. When this short amount of

time elapses, however, the numbers are erased from the memory. How did the information get there in thefirst place? Information that makes its way to the short term memory (STM) does so via the sensory storage

area. The brain has a filter which only allows stimuli that is of immediate interest to pass on to the STM, also

known as the working memory.

There is much debate about the capacity and duration of the short term memory. The most accepted theory

comes from George A. Miller, a cognitive psychologist who suggested that humans can remember

approximately seven chunks of information. A chunk is defined as a meaningful unit of information, such as a

word or name rather than just a letter or number. Modern theorists suggest that one can increase the capacity

of the short term memory by chunking, or classifying similar information together. By organizing

information, one can optimize the STM, and improve the chances of a memory being passed on to long term

storage.

When making a conscious effort to memorize something, such as information for an exam, many people

engage in "rote rehearsal". By repeating something over and over again, one is able to keep a memory alive.

Unfortunately, this type of memory maintenance only succeeds if there are no interruptions. As soon as a

person stops rehearsing the information, it has the tendency to disappear. When a pen and paper are not handy,

people often attempt to remember a phone number by repeating it aloud. If the doorbell rings or the dog barks

to come in before a person has the opportunity to make a phone call, he will likely forget the number

instantly.*Therefore, rote rehearsal is not an efficient way to pass information from the short term to long term

memory.*A better way is to practice "elaboraterehearsal". *This involves assigning semantic meaning to a

piece of information so that it can be filed along with other pre-existing long term memories.*

Encoding information semantically also makes itmore retrievable. Retrieving information can be done by

recognition or recall. Humans can easily recall memories that are stored in the long term memory and

used often; however, if a memory seems to be forgotten, it may eventually be retrieved by

prompting.The more cuesa person is given (such as pictures), the more likely a memory can be retrieved.

This is why multiple choice tests are often used for subjects that require a lot of memorization.

1. According to the passage, how do memories get transferred to the STM?

A) They revert from the long term memory.B) They are filtered from the sensory storage area.

C) They get chunked when they enter the brain.

D) They enter via the nervous system.

The correct answer isB. This is a factualquestion.

2. The word elapsesin paragraph 1 is closest in meaning to:

A) passes

B) adds up

C) appearsD) continues

The correct answer isA.This is a vocabularyquestion.

3.

All of the following are mentioned as places in which memories are stored EXCEPT the:

A) STM


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B) long term memory

C) sensory storage area

D) maintenance area

The correct answer isD. This is a negative factualquestion.

4. Why does the author mention a dog's bark?

A) To give an example of a type of memory

B) To provide a type of interruptionC) To prove that dogs have better memories than humans

D) To compare another sound that is loud like a doorbell

The correct answer isB. This is an author purposequestion.

5. How do theorists believe a person can remember more information in a short time?

A) By organizing it

B) By repeating it

C) By giving it a name

D) By drawing it

The correct answer isA. This is a factualquestion.6.

The author believes that rote rotation is:

A) the best way to remember something

B) more efficient than chunking

C) ineffective in the long run

D) an unnecessary interruption

The correct answer isC. This is a factualquestion.

7. The word itin the last paragraph refers to:

A) encoding

B) STM

C) semantics

D) information

The correct answer isD. This is a referencequestion.

8. Which of the following is NOT supported by the passage?

A) The working memory is the same as the short term memory.

B) A memory is kept alive through constant repetition.

C) Cues help people to recognize information.

D) Multiple choice exams are the most difficult.

The correct answer isD. This is a negative factualquestion.

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