VOA慢速英语2016 恐龙数量在小行星撞击地球前就已减少分享到:（在线收听）

Dinosaurs Already Decreasing Before Asteroid Hit 恐龙数量在小行星撞击地球前就已减少分享到:

Dinosaurs—those big prehistoric creatures— may have already been decreasing in population long before an asteroid crashed into the Earth, and killed them.

恐龙是一种史前大型生物，其实在小行星撞击地球将其灭绝之前，它们的数量就已经在减少了。

Until now, it was thought that an asteroid, or meteorite, that hit the Earth 66 million years ago was the main reason the reptiles became extinct.

迄今为止，人们都认为6600万年前小行星撞击地球（又说陨石撞击地球），是导致恐龙灭绝的主要原因。

But a new study finds that they may have already been decreasing in numbers millions of years before that.

但是，一项新的研究表明，其实在小行星撞击地球的几百万年前，恐龙数量就已经在减少了。

Dr. Manabu Sakamoto is a dinosaur expert – a paleontologist – at the University of Reading in the United Kingdom.He led the research in the new study.

衫本·坂本博士是英国雷丁大学的恐龙专家，还是古生物学者。他是本次研究项目的领导者。

“We were not expecting this result,” Sakamoto said.

坂本称：“我们没有预料到这个结果”。

The effect of the asteroid hitting the Earth is still considered the main reason for the dinosaurs’ final disappearance, Sakamoto said.But, he added, “it is clear that they were already past their prime in an evolutionary sense.”

坂本称，目前人们认为恐龙最终消失的主要原因是小行星撞击地球。但他补充道：“从进化的角度来讲，当时恐龙的发展已过全盛时期。”

In other words, Sakamoto means that dinosaurs were already starting to disappear from the land before the asteroid struck the Earth.

换言之，坂本的意思是，小行星撞击地球前，恐龙就已开始逐步消失了。

The researchers studied the fossil record.Fossils are remains of plants or animals that lived in ancient times that one can now see in some rocks.

调查者们研究了化石记录。化石是动植物的残骸，这些动植物生活在古代，当今人们在一些岩石中还可看到。

The new study says that 50 million years before the asteroid struck Earth, there was a decline of all types of dinosaurs.The long-necked sauropods were decreasing more quickly than other kinds of dinosaurs. The population of dinosaurs like the fierce Tyrannosaurus rex was decreasing at a slower rate than other dinosaurs.

新的研究表明，小行星撞击地球的5000万年前，恐龙的种类就在减少。长颈蜥脚类恐龙是所有恐龙种类中减少最快的。而凶残的雷克斯霸王龙的数量则下降相对较慢。

Sakamoto called the results of the study “groundbreaking.”

坂本称这次研究的结果“具有突破性”。

“Once again, it will change our understanding of the fate of these mighty creatures,” Sakamoto said.

坂本称：“这个调查结果再一次转变了我们对这些强大生物命运的理解”。

He also said that while the asteroid may have been what finally led to their extinction, “something else had already been preventing dinosaurs from evolving new species as fast as old species were dying out.”

他还说，虽然小行星可能是最终导致恐龙灭绝的原因，但还有一些别的因素导致恐龙新物种的进化速度较慢，赶不上旧恐龙物种的灭绝速度”。

Sakamoto said this suggests that for tens of millions of years before they finally died out from the asteroid effects, dinosaurs were beginning to lose their position as the leading animals on Earth. Dinosaurs ruled the Earth for about 150 million years.

坂本说，这意味着恐龙在最终受到小行星影响而灭绝的数千万年前，就已经失去了地球动物之王的地位。恐龙统治地球大约一亿五千万年。

Mike Benton was the co-author of the new study. He is a paleontology professor at the University of Bristol. He said the dinosaurs had lost their ability to evolve – or change – quickly enough to deal with environmental changes on the planet.Some of these changes came from volcanic activity and the breaking up of continental landmasses.

麦克·本顿是该研究报告的合著者。他是布里斯托大学的古生物学教授。他称，恐龙已不能通过进化或改变来敏捷应对地球上的气候变化。其中一些改变来自于火山活动，或大陆板块的分离。

When the asteroid hit the Earth, its force was so strong. It blew rocks and dust and particles up into the atmosphere, covering the Earth. That stopped the sunlight from reaching the ground, so plants could not grow. With their food supply gone, the dinosaurs died off too.

小行星撞击地球威力巨大。地球被卷入大气中的岩石、尘土和各种粒子覆盖。因为阳光无法穿透这些物质照射到大地上，所以植物无法生长。恐龙没有了食物来源，也慢慢地死去。

Some scientists believe the asteroid hit the Earth in an area that is now part of Mexico.

一些科学家坚信，小行星撞击地球的位置位于现在墨西哥的某个地区。

The study is published in the journal Proceedings of the National Academy of Sciences.

美国国家科学院的期刊发表了这项研究报告。

Words in This Story

extinct – adj. no longer exist, or alive

paleontologist – n. a person who studies the fossils of animals and plants that lived a long time ago, including dinosaurs

prime – adj. time when they are at their best

evolutionary - adj. changes and development over time

groundbreaking – adj. introducing new ideas or methods

fate – n. a power that is believed to control what happens in the future