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Humans belong to a large and proud lineage
人类属于一种
of animals known as bilaterians.
叫做两侧对称动物的庞大世系
Bilaterian because we are all bilaterally symmetrical;
这是因为我们的身体是对称的
you can draw a line down the middle of us
你可以在中间从上向下画一条线
and each half is basically a reflection of the other.
每一半基本上都和另一半可以重叠
Paleontologists have long suspected that
古生物学家很早以前就猜想
our lineage arose more than 550 million years ago
我们的世系发源于5.5亿多年以前的
in the Ediacaran Period,
埃迪卡拉纪
just before animals of all shapes exploded in diversity during the Cambrian.
即在动物多样性爆炸增长的寒武纪之前
But the only solid evidence
但是迄今为止
they could find of these long lost ancestors
他们能够发现关于古老的祖先的确凿证据
were tiny horizontal tunnels
也仅仅是在沙化石中
preserved in fossilized sand…until now.
保留下来的水平的小坑道
This week, researchers publishing in the
本周 科研人员在美国
Proceedings of the National Academy of Sciences
国家科学院院刊上发表文章
describe wormlike fossils that date back over half a billion years!
描述了这种可以追溯到5亿多年前的虫状化石
For decades, paleontologists have been intrigued
几十年以来 古生物学家一直被这些
by small, curved, linear grooves
很小的 或直线或弯曲的凹槽吸引着
found in rocks that date back more than half a billion years.
它们被发现在有着超过5亿年历史的岩石中
These suspected burrows, dubbed “Helminthoidichnites”,
这种可疑的洞穴叫做Helminthoidichnites
have been found all over the world.
它们在世界各地都已经被发现
And many experts agree that they are evidence
并且许多专家认为它们是
that tiny bilaterians wiggled around in the Ediacaran.
小型双侧对称动物在埃迪卡拉纪出现的证据
But there were other organisms living back then
但是那时也有很多其他生物的存在
that aren’t directly related to modern animals.
尽管那些生物和现代动物并没有直接关系
And no one could find fossils of the burrow-makers themselves.
另外 没有人能够找到建造洞穴的生物的化石
Then, researchers from the University of California Riverside
然后 来自加利福尼亚大学河滨分校的科研人员
noticed some strange, tiny, oval-ish divots
在检查这些古老的洞穴化石时
while examining some of these ancient burrow fossils.
注意到了一些奇怪而细小的椭圆形草皮
In fact, these teeny impressions were in the same layer as the tunnels,
事实上 这些微小的痕迹和坑道处于同一层
which meant they probably existed at the same time.
意味着它们可能存在于同一时期
So, the team used special 3D laser scanners
所以 团队成员使用3D激光扫描仪
to create detailed images of the impressions.
来获取这些痕迹的细节图象
Those revealed that the divots were imprints of
这些发现表明 草皮是一种
cylindrical creatures with
身体上有着微小肌肉凹槽的
tiny muscular grooves on their bodies.
圆柱形生物留下的印记
Whatever made these fossils would’ve been
不管这些化石由什么组成
one to two millimeters wide
它们的宽度都只有1到2毫米左右
and anywhere from 2 to 7 millimeters long;
并且任何地方的长度都在2到7毫米内
a perfect fit for those mysterious burrows!
这与那些神秘洞穴的尺寸完美符合
And they probably had many of the same features that
并且 它们可能与你我
you, and I, and other bilaterians have today.
以及现在的其他双侧对称动物 有很多相似之处
For instance, the scans showed that
举例来说 扫描图显示
one end was wider than the other,
一段比另一端要更宽
which likely means that they had a front and a back.
这可能意味着它们形成了首端和尾端
I know that, maybe like, having a front end and a back end
我知道 或许形成首端和尾端
might not sound that remarkable,
听起来没有这么值得称道
but in the Ediacaran, it was.
但是 这在埃迪卡拉世纪是非凡的
Plus, the researchers think they munched
另外 科研人员认为它们咀嚼
their way through a mat of microbes on the ocean floor,
海底的微生物垫来开辟道路
so they must have had mouths, guts, and anuses.
因此它们必须具备嘴 肠道以及肛门
The team decided to call these worm-like creatures Ikaria wariootia
于是这个团队决定 把这些像蠕虫一样的生物
after the Indigenous Australian names for the site where the fossils were found.
以化石发现地的澳大利亚土著名字命名 称之为Ikaria wariootia
And it probably pushed the origin of bilaterians back by millions of years,
尽管还不能研究出这些岩石的具体存在时期
though the rocks examined haven’t been conclusively dated.
双侧对称动物的起源又向前推了几百万年
These mini worms could have even been the first bilaterians,
这些小型的蠕虫甚至可能是首个双侧对称动物
that is, the first animals to have
也就是说 它们是第一批
the full set of bilaterian traits.
有着全部双侧对称动物特征的生物
Though, even if they weren’t,
就算不是这样
they can help paleontologists peer into the past
它们也帮助了古生物学家窥探过去
and gain a better understanding of how we ended up with
并对我们现在拥有的
the wonderful diversity of organisms we have today.
丰富多样的生物类别有了更好的了解
Speaking of wonderful complexity:
说到生物的多样性
in a new paper published this week in Cell Reports,
在《Cell Reports》中新发表的一篇论文
researchers have mapped and visualized the physical structure
科研人员观测并绘制出了
of the microscopic communities growing on human tongues.
人类舌头上生长的微观群落的物理结构
Here’s what one of those communities looks like.
这是其中一个群落的样子
The gray stuff in the middle is tongue tissue, and
在中间的灰色部分就是舌头组织
all those colorful spots are microbes.
所有彩色的斑点是微生物
Beautiful, right?
是不是很漂亮？
Who’d have thought tongue bacteria could be so pretty.
谁能想到附着在舌头上的细菌竟然如此美丽
And this image isn’t just stunning.
并且 这个图像不仅仅是让人惊叹于它的美丽
It demonstrates that we can take detailed pictures of our microbial mouth residents,
它表明我们可以给口腔里居住着的微生物拍照
which oddly enough,
尽管听上去有点奇怪
may help us learn about their role
但这或许可以帮助我们了解
in protecting our hearts.
它们在保护心脏方面的作用
It’s no secret that lots of different bacteria
大量不同的细菌
live in people’s mouths.
生活在人类的口腔中已经不是一个秘密
Microbial DNA from oral swabs
几十年以前 科学家就通过口腔拭子上
told scientists that decades ago.
携带的微生物DNA发现了这一点
But it wasn’t clear exactly where these bacteria are.
但是这些细菌具体在哪里仍不明确
Knowing that could help researchers
如果能够知道它们的具体位置
figure out how these microbes
科研人员就可以弄清楚这些微生物相互之间
interact with one other and with our cells,
以及和我们的细胞之间是如何交流的
an idea known as spatial ecology.
这属于空间生态学的范畴
That way, we can get a better idea of how they impact us.
那样 我们就能够更好的理解它们如何影响我们
So, over the past decade, the researchers have been
所以 在过去的十年中 科研人员致力于
developing an imaging technique
发展一种叫做
called CLASI-FISH
光谱成像-荧光原位杂交 的成像技术
which lets them distinguish between similar-looking microbes
这项技术让他们在放大细菌群落时
when they zoom in on bacterial communities.
可以区分外观相似的微生物
Essentially, this technique labels microbes with fluorescent pigments
这项技术的本质是把荧光分子
by attaching those pigments to genetic material
附着在与微生物遗传分子匹配的遗传物质上
that match to the microbe’s genetic molecules.
从而用荧光色素标记微生物
For this new study,
在这项新的研究中
21 volunteers scraped the tops of their tongues
21名志愿者用试纸刮取了舌尖
to provide a film of bacteria, saliva, and tongue cells,
并得到了细菌 唾液和舌头细胞的薄膜
which was then preserved with ethanol or formaldehyde.
随后将其浸泡在乙醇或氯仿中
Next, it was time to add some color.
下一步 是时候为它们染色了
Different kinds of bacteria got their own fluorescent pigments,
不同种类的细菌被染上了不同的荧光色素
so when the researchers shined different colors of light on them,
因此 科研人员用不同颜色的光照射它们
they could see where they were.
这样他们就能看到细菌的所在位置
Then, they combined images of all those colors
然后 他们把所有颜色混合到一张图像中
to build the beautiful maps.
来绘出美丽的图像
Though everyone’s tongue microbes were slightly different,
尽管每个人舌头上的微生物略有不同
it was clear right away that the bacterial communities had lots of structure to them.
显然 细菌群落有许多结构
Certain bacteria tended to attach themselves directly to tongue cells,
有的细菌倾向于把它们自己直接附着在舌细胞上
while others preferred the edges of the microbial moshpit.
而其他的喜欢栖息在微生物菌毛上
These patterns likely arise from differences
这些模式可能是由于
between the various microbes’ physiological needs.
各种微生物的生理需要之间的差异引起的
And the researchers in the study think
此外 在这项研究中科研人员认为
our cells might play a role in creating ideal homes
或许我们的细胞为不同的物种提供了
for different species to encourage their growth.
适宜条件来支持它们生长
They noted that many of these microbes are able to strip an oxygen from a nitrate
他们指出 许多这些微生物都能从硝酸盐中获得氧气
to make nitrite, a molecule that
从而生成亚硝酸盐
can be used to make nitric oxide.
这是一种可用于制造一氧化氮的分子
So it may be that our oral microbes help us make
所以 我们口腔的微生物帮助我们
more nitric oxide
制造更多的一氧化氮
than we’d be able to otherwise, and that,
这比我们本身能制造的多
in turn, has real impacts on our health.
也影响着我们的健康
See, among other things, nitric oxide helps regulate blood pressure.
其中 一氧化氮有助于调节血压
And recent studies have found that
近期研究还表明
higher activity of our oral microbes
我们口腔中更高活性的微生物
is associated with lower blood pressure.
与更低的血压水平有关联
So researchers in this experiment think that
因此 在这个实验中科研人员认为
our tongues may be cultivating these bacteria
我们的舌头也许培养这些细菌
to improve our health.
以提高我们的健康水平
But they’ll need to study the communities and their structure more
但他们需要进一步研究菌落和其结构
to discern all the details,
来辨明所有细节
like for example, how to best use this information
比如如何最好地利用这些信息
to improve people’s lives.
来改善人们的生活
And the team is excited to image other microbiomes, too,
团队还致力于拍摄其他微生物群
to better understand the mysterious workings of the microbial world.
以便更好地了解微生物世界中不可思议的杰作
Thank you for watching this episode of SciShow News!
感谢您收看科学秀的新闻
And especially, thank you to all of you who are patrons of the show on Patreon.
特别要感谢所有对Patreon的赞助者
We wouldn’t be able to make our weekly science news episodes
如果不是你们对我们Patreon社区的支持
if it weren’t for the support of our Patreon community.
我们将无法每周更新科学新闻短片
We wouldn’t be able to make most of our episodes, in fact.
事实上 如果没有你们 我们将不能制作大多数短片
Our patrons not only support us, they also inspire us and help us
我们的赞助者不仅支持并启发我们 还通过问题和评论
come up with ideas for episodes with their questions, comments,
让我们想出制作视频的新点子
both here and on our patron-only Discord channel.
不仅仅是在这里 也在我们专为赞助者的Discord频道
So thank you patrons, for being awesome.
因此 感谢您的惠顾
And if you want to join this community or learn more about it,
此外 如果您想要加入我们或是了解更多信息
you can go on over to Patreon.com/SciShow.
您可以登录Patreon.com/SciShow
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