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科学美国人60秒:它可能是我们已知最古老的祖先

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Tiny Wormlike Creature May Be Our Oldest Known Ancestor

它可能是我们已知最古老的祖先

Half a billion years ago, there existed a wormlike creature the size of a grain of rice. And a new study finds that this animal may have been the first to crawl around the seafloor, gobble up organic matter at one end and poop it out the other end. The creature, dubbed Ikaria wariootia, was probably one of our oldest relatives.

5亿年前,有一种像虫子一样的生物,有一粒米那么大。一项新的研究发现,这种动物可能是第一个在海底爬行的动物,一端吞食有机物,在另一端排泄。这种生物被称为伊卡利亚瓦里尤蒂亚),可能是我们最古老的亲戚之一。

“Ikaria is maybe the oldest bilaterian animal that we find in the fossil record. So this is twice as old or more than things like dinosaurs.”

“伊卡利亚可能是我们在化石记录中发现的最古老的对称动物。它的年龄是恐龙的两倍甚至更多。”

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University of California, Riverside paleontologist Scott Evans. He says animals like sponges are even more ancient, but they lack the bilateral symmetry that characterizes most animals today.

加州大学河滨分校的古生物学家斯科特·埃文斯说道。他说,海绵动物甚至更古老,但它们缺乏今天大多数动物所具有的两侧对称的特征。

“So a front and a back, and a symmetrical left and right side. And bilaterians also have an opening for food to go in, an opening for waste to go out, and a gut connecting them, basically a tube. And really, most animals, everything from insects to mammals to us, those are all bilaterians that are around today.”

“前面和后面,左右两边对称。两侧动物两侧也有一个开口供食物进入,一个开口供废物排出,还有一个连接它们的肠道,基本上是一个管子。实际上,大多数动物,从昆虫到哺乳动物,再到我们人类,这些都是今天的两侧对称动物。”

Evans and his colleagues discovered the humble creatures in fossil layers from the Ediacara Hills of South Australia. They used 3D laser scanners from NASA to make high resolution images of Ikaria and the surfaces they lived on. The scans confirmed the animals’ bilateral body morphology and revealed the shape of the burrows they left from scavenging the seafloor.

埃文斯和同事们在南澳大利亚埃迪卡拉山脉的化石层中发现了这些不起眼的生物。他们使用美国国家航空航天局的3D激光扫描仪,对伊卡利亚岛及其表面进行高分辨率成像。扫描结果证实了这些动物的双侧身体形态,并揭示了它们在海底觅食时留下的洞穴形状。

“It probably had a body that was divided into what we refer to as modules or units or segments. And because of the way it moved through the sediment, we think it had muscles and probably moved similar to how an earthworm moves by sort of extending and contracting its body using those muscle groups.”

“它可能有一个身体,被分为我们所说的模块或单位或部分。因为它在沉积物中移动的方式,我们认为它有肌肉,可能和蚯蚓移动的方式相似,就是利用肌肉群来伸展和收缩身体。”

Later animals built off of Ikaria’s basic body morphology—which featured a small front end and a larger rear end.

后来的动物是根据伊卡利亚的基本身体形态建造的,其特点是前端小,后端大。

“It doesn't have a head or a tail, but it's starting that type of body organization by which things can build a head and a tail.”

“它没有头,也没有尾巴,但它开始形成一种身体组织,通过这种组织,可以形成头和尾巴。”

What’s more, Ikaria had the ability to sense the environment around it.

更重要的是,伊卡利亚有感知周围环境的能力。

“And sense where food was and where oxygen was, which is also a critical evolutionary step in these early animals.”

“感知食物在哪里,氧气在哪里,这也是这些早期动物进化的关键一步。”

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

这项研究发表在《美国国家科学院院刊》上。

It might not seem like we share that much with a 555-million-year-old fossil, but looks can be deceiving. There’s probably a little bit of Ikaria in all of us.

我们与5.55亿年前的化石似乎没有那么多共同之处,但外表可能具有欺骗性。我们每个人身上都有伊卡利亚的影子。

Tiny Wormlike Creature May Be Our Oldest Known Ancestor

Half a billion years ago, there existed a wormlike creature the size of a grain of rice. And a new study finds that this animal may have been the first to crawl around the seafloor, gobble up organic matter at one end and poop it out the other end. The creature, dubbed Ikaria wariootia, was probably one of our oldest relatives.

“Ikaria is maybe the oldest bilaterian animal that we find in the fossil record. So this is twice as old or more than things like dinosaurs.”

University of California, Riverside paleontologist Scott Evans. He says animals like sponges are even more ancient, but they lack the bilateral symmetry that characterizes most animals today.

“So a front and a back, and a symmetrical left and right side. And bilaterians also have an opening for food to go in, an opening for waste to go out, and a gut connecting them, basically a tube. And really, most animals, everything from insects to mammals to us, those are all bilaterians that are around today.”

Evans and his colleagues discovered the humble creatures in fossil layers from the Ediacara Hills of South Australia. They used 3D laser scanners from NASA to make high resolution images of Ikaria and the surfaces they lived on. The scans confirmed the animals’ bilateral body morphology and revealed the shape of the burrows they left from scavenging the seafloor.

“It probably had a body that was divided into what we refer to as modules or units or segments. And because of the way it moved through the sediment, we think it had muscles and probably moved similar to how an earthworm moves by sort of extending and contracting its body using those muscle groups.”

Later animals built off of Ikaria’s basic body morphology—which featured a small front end and a larger rear end.

“It doesn't have a head or a tail, but it's starting that type of body organization by which things can build a head and a tail.”

What’s more, Ikaria had the ability to sense the environment around it.

“And sense where food was and where oxygen was, which is also a critical evolutionary step in these early animals.”

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

It might not seem like we share that much with a 555-million-year-old fossil, but looks can be deceiving. There’s probably a little bit of Ikaria in all of us.


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