【生态环保、自然灾害类】话题阅读练习（四） （阅读理解9篇+语法填空3篇） Passage 1 In general, the riches of the natural world aren't spread evenly across the globe. Places like the Tropical. Andes in South America are simply packed with unique species, many of which can't be found in any other places. Until recently, the main explanation for the biological riches concentrated in places like the Amazon Basin was that such places must be engines of biodiversity, with new species evolving at a faster rate than other parts of the world. But now, new research on bird evolution may turn that assumption on its head, instead supporting the idea that areas with fewer species actually tend to produce new species faster. The researchers say these biodiversity "cold spots" are generally found in environments featuring freezing, dry and unstable conditions. Though the researchers found these locations with few bird species tend to produce new ones at high rates, they fail to accumulate many species because the unstable conditions frequently make the new life forms die out. The more well-known " hot spots", by contrast, have accumulated their large numbers of species by being warm, hospitable and relatively stable. Indeed, the researchers found that the countless bird species that call the Amazon home tend to be older in evolutionary terms. "New species do form in places like the Amazon, just not as frequently as in the dry grasslands in the Andes ," says Elizabeth, an evolutionary biologist. The researchers managed to collect 1,940 samples representing 1,287 of the 1,306 bird species from South America. Their analysis showed that the best predictor of whether an area would produce new species at a high rate was how many species lived there, rather than climate or geographic features like mountains. Species-rich areas tended to produce new species more slowly. " Maybe bad environments generate new species more frequently because there's less competition and more available opportunities for new species," says Gustavo Bravo, a lead researcher. The study's findings add new urgency to protect ecosystems that may look barren, but may actually be nature's hothouses for the evolution of new species. 1. Why is South America mentioned in the first paragraph A. To make a comparison. B. To introduce the topic. C. To explain a fact. D. To draw a conclusion. 2. What determines the rising rate of new species in place A. The number of its then species. B. The environment they lived in. C. The survival skills of species. D. The different biological factors. 3. Which of the following can best explain the underlined word " barren" in the last paragraph A. Dry and bare. B. Lively and active. C. Nice and green. D. Complex and unpredictable. 解析： B 推断 第一段讲到南美洲物种丰富,普遍认为是物种进化快的结果。但是一项新研究却认为物种少的地方产生新物种的速度更快。由此可知，提到南美洲是为了引出话题，提出该研究的观点。故B项正确。 A 理解具体信息 根据第一段中的"areaswith fewer...new speci ... ...
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