There is something intrinsically fascinating about the idea of evolution. What principles govern the evolution of a species? And what does evolution tell us about the place of Homosapiens in the grand order of things? The writer George Bernard Shaw held that a mystical guiding force impels life to evolve toward eventual perfection. Modern scientists may not believe in this guiding force or in the possibility of perfection, but many would agree that life has been improving itself through evolution for billions of years. (Note that this conveniently makes Homosapiens, a very recent product of evolution, one of the newest and most improved versions of life.) In the view of these scientists, constant competition among species is the engine that drives the process of evolution and people’s life upward. To Darwin, nature was a surface covered with thousands of sharp wedges, all packed together and jostling for the same space. Those wedges that fared best moved toward the center of the surface, improving their position by knocking other wedges away with violent blows. The standard example that textbooks give of such competitive wedging is the interaction between the brachiopods and the clams. Clams were long held to be ancient undersea competitors of brachiopods due to the fact that the two species inhabited the same ecological niche. Clams are abundant today, whereas brachiopods (dominant in ancient times) are not. Modern clams are also physiologically more complex than brachiopods are. The standard interpretation of these facts is that the clams’ physiology was an evolutionary improvement that gave them the ability to “knock away“ the brachiopods. In recent years, however, the prominent naturalists Stephen Jay Gould and C. Brad Calloway have challenged the validity of this example as well as the model it was meant to support. Gould and Calloway found that over most geological time clams and brachiopods went their separate ways. Never did the population of brachiopods dip as that of the clams rose, or vice versa. In fact, the two populations often grew simultaneously, which belies the notion that they were fighting fiercely over the same narrow turf and resources. That there are so many more clams than brachiopods today seems rather to be a consequence of mass deaths that occurred in the Permian period. Whatever caused the mass deaths — some scientists theorize that either there were massive ecological or geological changes, or a comet crashed down from the heavens — clams were simply able to weather the storm much better than brachiopods. Out of these observations, Gould and Calloway drew a number of far-reaching conclusions. For instance, they suggested that direct competition between species was far less frequent than Darwin thought. Perhaps nature was really a very large surface on which there were very few wedges, and the wedges consequently did not bang incessantly against each other. Perhaps the problem facing these wedges was rather that the surface continually altered its shape, and they had to struggle independently to stay in a good position on the surface as it changed. So where does that leave Homosapiens if evolution is a response to sudden, unpredictable and sweeping changes in the environment rather than the result of a perpetual struggle? No longer are we the kings of the mountain who clawed our way to the top by advancing beyond other species. We are instead those who looked to the mountains when floods began to rage below and then discovered that living high up has its definite advantages, so long as our mountain doesn’t decide to turn into a volcano.

What does the author attempt to express by using the parenthetical statement in Paragraph 1?

A．Scientists intend to show that their own species is superior to others.

B．Scientists want to highlight the concept of evolution as a process of gradual improvement.

C．Human race has evolved from lower forms of life toward eventual perfection.

D．Human race is as close to perfection as life hopes to reach.

The author cites “clams“ and “brachiopods“ underlined in Paragraph 2 as examples to show that______.

A．clams were biologically stronger than brachiopods

B．brachiopods were inherently weaker than clams

C．clams and brachiopods could not coexist

D．interspecies compete according to Darwin and his “wedge“ model

According to Gould and Calloway’s theory, the decline of brachiopods______.

A．resulted from their competition with clams

B．seemed to have been caused by an environmental impact

C．were not triggered by a comet crashing down from the heavens

D．might be the consequence of mass deaths in the Permian period

The word “comet“ underlined in Paragraph 3 refers to______.

A．an event that could have obscured the geological record

B．a possible cause for the decline of brachiopods

C．massive ecological or geological changes

D．the acceleration of evolutionary adaptation

According to Gould and Calloway’s theory, evolution______.

A．may not necessarily be based on competition

B．occurs through the differential survival of competing genes

C．is the consequence of the struggle for resources among species

D．is the product of heredity, environmental stimuli, and past experiences

The last paragraph attempts to______.

A．outline Gould and Calloway’s research on clams and brachiopods, which contradicts Darwin’s theories

B．explain Gould and Calloway’s theory which claims that environmental change is more important than competition in the survival of species

C．restate the concept of evolution as a process of gradual improvement which leads to the survival of superior species

D．explore the implications for the status of humans in light of Gould and Calloway’s new theory about evolution

With regard to Gould and Calloway’s theory of evolution, the author would most likely state that it______.

A．has not yet been tested as much as the previous model

B．rules out the possibility that one species could cause the extinction of another

C．puts the status of humans in a new perspective

D．attaches less importance to the effect of natural disasters

What is the main idea of the passage?

A．It criticizes Darwin’s evolutionary theory.

B．It discusses a new alternative to an established theory.

C．It examines the nature of the interaction between two species.

D．It demonstrates Gould and Calloway’s conclusions about clams and brachiopods.

It can be inferred from Gould and Calloway’s findings about clams and brachiopods that

A．the two species never competed for the same turf

B．they fought fiercely for the same resources

C．clams had genetic ability to evade disasters

D．brachiopods were physiologically less complex than clams

In significant parts of Eurasia, the middle centuries of the first millennium______a significant transition in human cultural history. define mark identify specify

It can sometimes feel like the world is very noisy — from planes arching loudly through the sky to the______buzz of your cellphone. unavailing unassuming unconvincing unceasing

Sub-Saharan Africa and Southeast Asia are most at risk from bat viruses______humans and causing new diseases that could lead to deadly outbreaks. vaulting bouncing attacking hurdling

Poland is somewhat a new destination for Chinese tourists, and Warsaw, the capital city, is an important business center with______night life and elegant dining. sophisticated sluggish sloppy solitary

In this new world the most dangerous conflicts will not be between social classes or other economically defined groups, but between peoples belonging to different cultural______. parts components entities sects

Certain religious and political groups felt novels had the power to make immoral characters so interesting that younger readers would______with them easily. agree comply identify differentiate

The mayor is ideologically consistent. His long-term commitment to education reform, for example, is not a sign of fickleness. coolness carefulness calmness capriciousness

Under the attack of its enemies from all sides, the empire was about to crumble. disintegrate disembark disgrace disengage

Despite her relaxed style, Ms. Flagen is a canny businesswoman who knows how to aggressively market her brand. thrifty shrewd cunning amicable

The problem of avoiding duplicate names, such as for E-mail accounts, is particularly acute when only a finite number of possibilities are allowed. solemn stern stiff severe

The environmentalists’ warning against the blatant pursuit of industrialization without caution seems especially prescient. precarious superficial foresighted mysterious

Britain is attractive to worldwide advertisers because it is a homogenous market, so there is no need to tailor advertisements to different parts of the country. global local foreign uniform

A discovery in New Jersey actually contributed to the early economic development of the U.S. and, in 1714 a worker uncovered a green rock containing copper. when, in 1714, thus, in 1714, it was in 1714 till in 1714

A study found that the environmental costs of producing and recycling paper cups were as high as, if not higher than, to produce and recycle polystyrene cups. those of producing and recycling that of producing and recycling which produced and recycled that produced and recycled

Blue lights flashing and siren blaring, the police car sped through the busy intersection. Blue lights flashed and siren blared To flash blue lights and blare siren With blue lights and siren flashing and blaring With blue lights flashing and siren blaring

Linguistic research often requires a period of fieldwork where the linguist can study and record the spoken dialects of a region. through which during which with which by which

Veterans of World War II received greater support from the general public than later wars. than did than what did than did those of than of those

Volunteering on political campaigns can help students become a more attractive candidate for jobs in government. become more attractive candidates become a candidate more attractive becoming candidates more attractive becoming a candidate more attractive

About 75 percent of all cadmium is used for cadmium plating of metals are easily corroded such as iron and steel. metals easily corroded corroded metals easily corroded easily metals easily corroded metals

Most fishes and many reptiles have ribs along most of the spine, but in mammals finding them only in the chest area. they find which they find they are found which they are found