地球上最古老的10種生物(上)
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?
這份名單羅列了地球上最古老的生物，其中涵蓋了動物、物種和微生物，看完後你一定覺得自己很年輕。可能有人會對名單吹毛求疵，以爲其中某些生物不過區區百萬年歷史，但實際上它們都是相當久遠的存在。那麼地球上最古老的生物到底有哪些呢？更重要的是它們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?
這些古生物已經有上億年甚至數十億年的歷史了，爲了更適應生存環境，長久以來它們持續進化，至臻完美。在進化過程中它們的尾巴也許會消失，也許會長出新觸手，抑或進化出更精簡有效的保護殼。不過，如果有個人從高中就開始剪頭髮，這些生物會疑惑：如果頭髮實用，爲什麼還要剪掉呢？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.
當人類滅絕併成爲擱在一堆塑料盒中的化石後，這些地球上最古老的生物也許還會一如既往地存活下去。
obacteria
1.藍藻細菌Age: 3.5 billion years old
年齡：35億歲
The 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.
已知的最古老的藍藻菌化石在澳大利亞西部的太古巖中被發現。藍藻細菌又名藍綠藻，是一種能利用光合作用生成能量的細菌。人們認爲這一過程促進了大氣層中氧氣的形成，使地球更加適宜已知生命生存。ge
2.海綿Age: 580 million years old
年齡：5.8億歲
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.
海綿源自一個原始的動物門，這個動物門的歷史能追溯到生命起源。在澳大利亞、中國和蒙古境內的岩石中發現過玻璃海綿的化石。雖然現在所發現的海綿中約有90%都屬於尋常海綿綱，但此類海綿化石比其他類型的更加罕見，因爲它們的骨骼由相對柔軟的海綿硬蛋白組成，不易形成化石。yfish
3.水母Age: 505 million years old
年齡：5.05億歲
Jellyfish belong to the group of animals called Cnidaria or Coelenterata. This group includes corals, hydras, jellyfish, Portuguese men-of-war, sea anemones, sea pens, sea whips, and sea fans. They are hard to fossilize, as they're made of mostly water, but fossils suggest they are even older than previously thought.
水母與珊瑚、水螅、僧帽水母、海葵、海鰓、海鞭以及海扇同屬刺胞動物門，又名腔腸動物門。它們的身體幾乎由水組成，難以形成化石，不過現有的化石記錄表明它們比我們預想的更加古老。eshoe Crab
4.馬蹄蟹Age: 450 million years old
年齡：4.5億歲
Horseshoe crabs are considered "living fossils." The earliest horseshoe crab fossils are dated to the Ordovician period. These marine arthropods live primarily near shallow ocean waters with soft, sandy or muddy bottoms. Their populations have been in decline due to habitat destruction and over harvesting.
馬蹄蟹素有“活化石”之稱，最古老的馬蹄蟹化石可追溯到奧陶紀。這類海洋節肢動物主要棲息在柔軟的砂質或泥質底淺海區。由於棲息地遭到破壞以及過度捕撈，它們的數量一直在減少。acanth
5.腔棘魚Age: 400 million years old
年齡：4億歲
A rare order of fish, coelacanths are more closely related to lungfish, reptiles and even mammals than to common ray-finned fish. Live species have been discovered as recently as 1998.
腔棘魚是一種罕見的魚，相較常見的輻鰭魚，它們與肺魚、爬行動物甚至哺乳動物纔是近親。最近一次發現活體腔棘魚是在1998年。
