2017考研英语拓展阅读：恐龙衰亡的真相

　　考研英语阅读能力提升需要不断地积累练习，通过多阅读来积累词汇，提升阅读速度，强化把握主旨能力。2017考研复习之初，时间相对充裕，新东方在线建议大家每天多做一些阅读，可娱乐也可增长见闻，还能提升能力。下面一篇文章是关于恐龙衰亡的真相。

2017考研英语拓展阅读：恐龙衰亡的真相

　　The dinosaurs were already in decline 50 million years before the asteroid strike that finally wiped them out, a study suggests.

　　一项研究显示，虽然小行星撞地球是导致恐龙灭绝的原因，但早在五千万年前恐龙数量已逐步衰减。

　　The new assessment adds further fuel to a debate on how dinosaurs were doing when a 10km-wide space rock slammed into Earth 66 million years ago.

　　在人们在争论恐龙究竟如何躲过6600万年前那个10km宽的太空陨石撞击地球时，这项新的评估为这场争论火上浇油。

　　A team suggests the creatures were in long-term decline because they could not cope with the ways Earth was changing.

　　一个研究小组称，由于不能适应地球的变化，恐龙在很长一段时间内数量衰减。

　　The study appears in PNAS journal.

　　这项研究刊登在美国科学院院刊。

　　Researchers analysed the fossil remains of dinosaurs from the point they emerged 231 million years ago up to the point they went extinct.

　　研究者对恐龙出现(2.31亿年前)直至灭绝期间的恐龙化石进行分析。

　　To begin with, new species evolved at an explosive rate. But things started to slow about 160 million years ago, leading to a decline in the number of species which commences at about 120 million years ago.

　　最开始，新物种以爆炸性的速度出现，但1.6亿年前这个过程开始放缓，导致在1.2亿年前恐龙数量开始减少。

　　Dr Manabu Sakamoto, a palaeontologist from the University of Reading, who led the research, said: "We were not expecting this result."

　　英国雷丁大学古生物学家Manabu Sakamoto博士主导这项研究，他说：“我们没料到是这样的结果。”

　　"Even though they were wiped out ultimately by the impact of the asteroid, they were actually already on their way out around 50 million years before the asteroid hit."

　　“尽管恐龙是由于小行星撞地球而灭绝，但在这之前，即距今约5000万年前，恐龙已经开始走向衰落。”

　　Mixed pattern

　　多重因素作用

　　Dr Sakamoto’s analysis shows that the long-necked giant sauropod dinosaurs were declining the fastest, whereas theropods, the group of dinosaurs that included the iconic Tyrannosaurus rex, were in a more gradual decline.

　　Skamoto博士的分析表明，长颈巨型蜥脚类恐龙衰亡速度最快，而兽角类恐龙- 代表性的如雷克斯霸王龙，数量下降缓慢。

　　Co-author Dr Chris Venditti, an evolutionary biologist from the University of Reading, told BBC News:

　　来自雷丁大学的演化生物学家、论文联合作者Chris Venditti博士告诉BBC：

　　"The current widespread view is that dinosaurs were reigning strong right up to the impact that hit the Earth - and it’s the impact that drove their final extinction," he said.

　　“目前普遍认为恐龙在小行星撞地球前统治着地球-而小行星撞击也是导致它们最终灭绝的原因。”他说。

　　"And while that’s certainly true, what we found was that they were on the decline long before that."

　　“这当然是事实，但我们发现它们早在那之前就已经走向衰亡。”

　　Dr Venditti believes that the dinosaurs’ 50 million year decline rendered them even more susceptible to the environmental catastrophe that followed the asteroid impact.

　　Venditti博士认为恐龙在5000万年前数量的减少导致它们更易受到小行星撞地球过后的环境大灾难影响。

　　"If they were reigning strong perhaps they would have fared much better than they did," he said.

　　“如果它们数量再多些，可能会更好地适应这种情况。”他说。

　　A study two years ago also indicated that some species were in decline, but only for the last few million years before the asteroid impact. The new research suggests that the problem began tens of millions of years earlier and affected a wider range of species.

　　两年前的一项研究同样表明，一些物种在衰退，但仅限于小行星撞地球的前几百万年。最新研究表明这个问题早在数千万年前就已经出现，并且对大范围的物种造成了影响。

　　So why were the dinosaurs in decline? No one knows but one possibility is an inability to cope with the way the environment was changing.

　　那么，恐龙究竟为何会衰亡?没人知道真正原因，但有一个可能是它们没有适应环境变化的能力。

　　Evolutionary pressures

　　进化压力

　　Conditions 230 million years ago were perfect for the dinosaurs when they first emerged, warm and lush from pole to equator.

　　2.3亿年前，恐龙刚出现时，地球环境非常适合它们生存，气候温暖，从两极到赤道动植物繁茂。

　　But as the climate cooled and sea levels shifted, the dinosaurs may have been subjected to new evolutionary pressures.

　　但随着气候变冷和海平面变动，恐龙可能面临新的进化压力。

　　Dinosaurs and mammals evolved at about the same time, but the former dominated the land surface for more than 100 million years.

　　恐龙和哺乳动物约在同一时期进化，但前者统治了地球超过1亿年之久。

　　The asteroid impact is commonly thought to have paved the way for mammals to take over. But the new study suggests that mammalian supremacy might have occurred eventually, without a space impact.

　　人们普遍认为，小行星撞地球为哺乳动物的翻身铺平了道路。但新的研究表明，即使小行星没有撞击地球，哺乳动物最终也会统治地球。

　　Co-author Prof Mike Benton of Bristol University, told BBC News: "World climates were getting cooler all the time. Dinosaurs rely on quite warm climates and mammals are better adapted to the cold.

　　论文联合作者、布里斯托大学德Mike Benton教授告诉BBC：“全球气候一直在变冷，恐龙适合在温暖的气候条件下生存，而哺乳动物更好地适应了寒气候。”

　　"So there might have been a switch over in any case without the asteroid impact."

　　“因此，无论是否有小行星撞地球，最终哺乳动物都会取代恐龙。”

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