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TEXT B For hundreds of years, farmers have selected and bred plants and animals to favour, or bring out, characteristics they desired.. For example, cows that produced large amounts of milk were selected for breeding, while poor milk producers were not allowed to reproduce. Similarly, horses were bred for speed and strength. Those having these desired characteristics were selected for breeding. Over time, these preferred breeds became more common than earlier, less desired types. This selective breeding is called artificial selection. The theory of evolution by natural selection was put forward in a joint presentation of the views of Charles Darwin and Alfred Russell Wallace before the Linnaean Society of London in 1858. Darwin and Wallace were not the first to suggest that evolution occurred, but their names are linked with the idea of evolution because they proposed the theory of natural selection as the mechanism by Which evolution occurs. We are always more likely to believe in a process when people explain how it happens than if they merely assert that it does. The theory of evolution by means of natural selection is based on three observations. First, as we can see by comparing one cat or human being with another, the members of a species differ from one another; that is, there is variation among individuals of the same species. Second, some of the differences between individuals are inherited. (Other differences are not inherited, but are caused by different environments. For instance, two plants with identical genes may grow to different sizes if one of them is planted in poor soil.) Third, more organisms are born than live to grow up and reproduce: many organisms die as embryos or seeds, as saplings, nestlings, or larvae. The logical conclusion from these three observations is that certain genetic characteristics of an organism will increase its chances of living to grow up and reproduce over the chances of organisms with other characteristics. To take an extreme example, if you have inherited a severe genetic disease of the liver, you have a much lower chance of living to grow up and reproduce than someone born without this disease. Inherited characteristics that improve an organism’s chances of living and reproducing will be more common in the next generation and those that decrease its chances of reproducing will be less common. Various genes or combinations of genes will be naturally selected from one generation to the next (that is, to cause evolution). It is not necessary that all genes affect survival and reproduction; the same result occurs if just some genes make an individual more likely to grow up and reproduce. To summarize: 1. Individuals in a population vary in each generation. 2. Some of these variations are genetic. 3. More individuals are produced than live to grow up and reproduce. 4. Individuals with some genes are more likely to survive and reproduce than those with other genes. Conclusion: From the above four premises it follows that those genetic traits that make their owners more likely to grow up and reproduce will become increasingly common in the population from one generation to the next. What would happen to inherited characteristics in the next generation in the process of natural selection
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Passage One As a wise man once said, we are all ultimately alone. But an increasing number of Europeans are choosing to be so at an ever earlier age. This isn’t the stuff of gloomy philosophical contemplations, hut a fact of Europe’s new economic landscape, embraced by sociologists, real- estate developers and ad executives alike. The shift away from family life to solo lifestyle, observes a French sociologist, is part of the "irresistible momentum of individualism" over the last century. The communications revolution, the shift from a business culture of stability to one of mobility and the mass entry of women into the workforce have greatly wreaked havoc on (扰乱) Europeans’ private lives. Europe’s new economic climate has largely fostered the trend toward independence. The current generation of home-aloners came of age during Europe’s shift from social democracy to the sharper, more individualistic climate of American-style capitalism. Raised in an era of privatization and increased consumer choice, today’s tech-savvy (精通技术的) workers have embraced a free market in love as well as economics. Modern Europeans are rich enough to afford to live alone, and temperamentally independent enough to want to do so. Once upon a time, people who lived alone tended to be those on either side of marriage-- twenty something professionals or widowed senior citizens. While pensioners, particularly elderly women, make up a large proportion of those living alone, the newest crop of singles are high earners in their 30s and 40s who increasingly view living alone as a lifestyle choice. Living alone was conceived to be negative dark and cold, while being together suggested warmth and light. But then came along the idea of singles. They were young, beautiful, strong! Now, young people want to live alone. The booming economy means people are working harder than ever. And that doesn’t leave much room for relationships. Pimpi Arroyo, a 35-year-old composer who lives alone in a house in Paris, says he hasn’t got time to get lonely because he has too much work. "I have deadlines which would make life with someone else fairly difficult. "Only an ideal woman would make him change his lifestyle, he says. Kaufmann, author of a recent book called "The Single Woman and Prince Charming," thinks this fierce new individualism means that people expect more and more of mates, so relationships don’t last long if they start at all. Eppendorf a blond Berliner with a deep tan, teaches grade school in the mornings. In the afternoon she sunbathes or sleeps, resting up for going dancing. Just shy of 50, she says she’d never have wanted to do what her mother did give up a career to raise a family. Instead, "I’ve always done what I wanted to do：live a self- determined life." What is said about European society in the passage
Passage ThreeQuestions 32 to 35 are based on the passage you have just heard.
Questions 19 to 21 are based on the conversation you have just heard.
Questions 22 to 25 are based on the conversation you have just heard.
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