下面PTE院校小编为大家带来一篇PTE双语阅读，来提高同学们的阅读量。

　　This list of the oldest living things on Earth, including the oldest animals, species, and organisms, will definitely make you feel young. You could probably nitpick some of these life forms within a million years here, a million years there... but the fact remains that these animals have been around a loooong time. What are the oldest living organisms on earth? And more importantly how have they stuck around this long?

　　这份名单罗列了地球上最古老的生物，其中涵盖了动物、物种和微生物，看完后你一定觉得自己很年轻。可能有人会对名单吹毛求疵，以为其中某些生物不过区区百万年历史，但实际上它们都是相当久远的存在。那么地球上最古老的生物到底有哪些呢?更重要的是它们是如何做到生生不息的呢?

　　These ancient organisms have been around for millions, or ever billions of years and have achieved apparent perfection in their environment. Millennia have passed, and they keep on keeping on. Sure, a tail might shorten, an extra tentacle might grow, or they might develop a more streamlined coat of armor... but, like that guy you know with the haircut he's had since high school, these animals have asked themselves the question: Why change it if it's working?

　　这些古生物已经有上亿年甚至数十亿年的历史了，为了更适应生存环境，长久以来它们持续进化，至臻完美。在进化过程中它们的尾巴也许会消失，也许会长出新触手，抑或进化出更精简有效的保护壳。不过，如果有个人从高中就开始剪头发，这些生物会疑惑：如果头发实用，为什么还要剪掉呢?

　　These are the oldest living things on the planet, and they just might still be here long after we are nothing more than fossils found buried in a pile of styrofoam take-out boxes.

　　当人类灭绝并成为搁在一堆塑料盒中的化石后，这些地球上最古老的生物也许还会一如既往地存活下去。

　　1.Cyanobacteria

　　1.蓝藻细菌

　　Age: 3.5 billion years old

　　年龄：35亿岁

　　oldest known cyanobacteria fossils were found on Archaean rocks of western Australia. Cyanobacteria, or blue-green algae, is a type of bacteria that uses photosynthesis to create energy. It is believed that this played a role in oxidizing the earth's atmosphere, making the planet more suitable for life as we know it.

　　已知的最古老的蓝藻菌化石在澳大利亚西部的太古岩中被发现。蓝藻细菌又名蓝绿藻，是一种能利用光合作用生成能量的细菌。人们认为这一过程促进了大气层中氧气的形成，使地球更加适宜已知生命生存。

　　2.Sponge

　　2.海绵

　　Age: 580 million years old

　　年龄：5.8亿岁

　　Sponges are from an ancient animal group whose lineage can be traced back to the beginnings of animal life. Fossils of glass sponges have been found in rocks in Australia, China, and Mongolia. Although about 90% of modern sponges are demosponges, fossilized remains of this type are less common than other types because their skeletons are composed of relatively soft spongin that does not fossilize well.

　　海绵源自一个原始的动物门，这个动物门的历史能追溯到生命起源。在澳大利亚、中国和蒙古境内的岩石中发现过玻璃海绵的化石。虽然现在所发现的海绵中约有90%都属于寻常海绵纲，但此类海绵化石比其他类型的更加罕见，因为它们的骨骼由相对柔软的海绵硬蛋白组成，不易形成化石。