VOA慢速英语2019 地球最早可移动生物追溯至21亿年前（在线收听）

Earth’s Earliest Mobile Organism Lived 2.1 Billion Years Ago

Scientists have discovered the oldest fossil evidence of organism motility, or the ability of an organism to move independently. The discovery shows that development of motility began more than two billion years ago.

科学家们发现了最古老的化石证据，证明了生物体的运动性，即生物体独立运动的能力。这一发现表明，运动能力的发展始于20多亿年前。

The fossils were found in Gabon, in rock called shale. Researchers described them as tube-like structures up to 170 millimeters long. They say the structures may have been created when the organisms moved through soft, wet dirt in search of food or a better environment.

这些化石是在加蓬的页岩中发现的。研究人员称其为“长达170毫米的管状结构”。他们说，这些结构可能是某种生物在柔软潮湿的泥土中觅食或更舒适的生存环境时行成的。

The researchers also said the organisms might have been moving together as a group. The organisms remains a mystery as the fossils are a record only of their movement.

研究人员还说，这些生物可能是作为群体一起移动的。这些生物的本体仍然成谜，因为这些化石只是它们运动的记录。

The researchers said the fossils dated back to a time when Earth was rich with oxygen. These conditions permitted simple life forms to develop more complexity.

研究人员说，这些化石可追溯到地球上氧气丰富的时代。简单细胞生命体才得以进化为复杂结构生命体。

Life on Earth started with single-celled bacteria about 4 billion years ago. The earliest life forms could not move under their own power. The Gabon fossils dated to the Paleoproterozoic Era are about 1.5 billion years older than the previous earliest evidence of organism motility.

地球上的生命始于约40亿年前的单细胞细菌。最早的生命体无法依靠自己的力量移动。加蓬的化石可以追溯到古元古代，比先前最早的生物活动的证据要推前15亿年。

Abderrazak El Albani, a scientist with the University of Poitiers in France, led the team in Gabon. The shale deposit there has proven to be a treasure for the study of ancient life. Several years ago, Albani and his team discovered it held the oldest fossils know of multicellular animals.

法国普瓦捷大学的科学家阿卜杜勒－埃尔·阿尔巴尼（Abderrazak El Albani）在加蓬领导了这一研究小组。当地页岩矿床已被证明是研究古代生命的宝库。几年前，阿尔巴尼和他的研究小组发现这里保存着已知的最古老的多细胞动物化石。

“What matters here is their astonishing complexity and diversity in shape and size, and likely in terms of metabolic, developmental and behavioral patterns, including the just-discovered earliest evidence of motility, at least for certain among them,” Albani said.

“重要的是它们在形状和大小方面惊人的复杂性和多样性，也有可能在代谢、发育和行为模式方面，包括刚发现的最早的运动性证据，至少这些发现是可以肯定的，”阿尔巴尼说道。

The first vertebrates, or animals with backbones, appeared about 525 million years ago. Dinosaurs came about 230 million years ago and human-like species developed about 300,000 years ago.

最早的脊椎动物出现在约5.25亿年前。恐龙大约出现在2.3亿年前，类人物种大约于30万年前形成。

Scientists believe this early time in motility may have faced a setback soon after the Paleoproterozoic Era, about the time of the Gabon fossils. The Earth saw a considerable loss of atmospheric oxygen at that time.

科学家们认为，这种早期的活动性可能在古元古代（大约是加蓬化石年代）后不久就开始发生倒退。当时地球大气中的氧气开始大量流失。

The research was published in the Proceedings of the National Academy of Sciences.

I'm Pete Musto.

Words in This Story

fossil – n. something, such as a leaf, skeleton, or footprint, that is from a plant or animal which lived in ancient times and that you can see in some rocks

deposit – n. an amount of a substance, such as oil or coal, that exists naturally in the ground

astonishing – adj. causing a feeling of great surprise or wonder

diversity – n. the quality or state of having many different forms, types, ideas, etc.

metabolic – adj. of or relating to the chemical processes by which a plant or an animal uses food, water, etc., to grow and heal and to make energy