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溶解化石以证明恐龙是恒温动物

We Dissolved Fossils To Prove Dinosaurs Were Warm Blooded | Science Skills

-You are the first person to see a bit of Sue’s blood vessels.
-你是第一个看见Sue的血管微观图的人
-Yes. -That’s rad. And you’re going to be the second.
-对 -真激动人心 你将是第二个
[Abby laughs]
[Abby笑声]
-Is this hollow branching shape
-那个中空分支型的
-Yes, yeah!
-对 看到了!
That Sue in question is Sue the T. rex,
我们研究的暴龙叫Sue
and we’re about to see proof that she was warm-blooded.
我们将验证她是恒温动物
We went to the Field Museum to see how they work their magic.
我们去菲尔德博物馆 看看研究人员如何进行神奇的工作
Our first stop was …
第一站是……
So, here is our dinosaur and oversize collections.
这儿有我们的恐龙和大件物品
-That’s Jingmai O’Connor, and she —
-你将见到邹晶梅 她……
you know what? I’ll let her tell you.
我会请她自我介绍的
Yeah, I would say I’m one of
我可以说我是
the world’s experts on Mesozoic birds.
研究中生代鸟类的世界级专家之一
Not to brag or anything. Nah, I’m just kidding.
不为吹牛或别的 就开玩笑
-And one of the key questions she asks
-她在研究中提的一个重要论题
with her research is why birds were the only dinosaurs
就是为什么鸟类是恐龙中唯一
to survive the Cretaceous-Paleogene extinction.
在白垩纪-古近纪灭绝事件中存活的
We need to look at birds, and then we need to back up from birds
我们需要观察鸟 然后从鸟类出发
and look at the dinosaurs closely related.
再研究与鸟类相近的恐龙
I think it’s kind of funny,
这听起来很滑稽
but we have a drawer full of bits of Sue.
但我们的确有满满一抽屉Sue的碎片
When you have the edge of the puzzle,
当你拼图才拼到边上的时候
that’s the easiest part to do, right?
最简单 对吧
The inside of the puzzle is harder to put together.
可要把里面部分拼好 就更困难了
So these are like the inside puzzle bits.
这些就相当于是内部的拼图块儿
You can’t figure out where they go,
你搞不清楚 要怎样拼在一起才好
but this is to our advantage,
但我们有信心克服
because these are the type of fragments
因为 这是一类允许我们
that it’s OK for us to do destructive analyses on.
进行损毁分析的碎片
-The destruction of these rare and one-of-a-kind fossils
-对这些珍稀 独一无二的碎片的损毁分析
can involve slicing or dissolving in acid.
包括切片和酸水溶解
Slicing allows the scientists to study specimens histologically.
切片能让科学家 从组织学角度研究样本
You have to cut a piece of the bone, remove it,
你得切割一块骨头 取出来
grind it down so it’s really thin so that light can pass through it
把它研磨非常细 这样光线才能穿过
so you can study it under a microscope.
你才能用显微镜观察它
It’s a cost-benefit analysis essentially, right?
这本身是成本效益分析 对吗?
What are the questions you’re trying to answer?
你要回答什么问题呢?
Is it worth it to damage this extremely rare, important fossil?
破坏如此稀有珍贵的碎片来进行研究 是否值得呢?
To show me how it’s done,
为展示如何切割
they demonstrated with a prehistoric bird bone.
他们用一块史前鸟类的骨头做示范
-You’re going to bring it to, in our case, Akiko Shinya
-像我们这种情况 要把骨头放进Akiko Shinya里面
She’s our chief fossil preparator. She’s amazing.
Akiko是我们主要的选矿机 好用得很
-Akiko starts by taking a small slice of the specimen.
-要使用Akiko 首先切一小片标本
-You then take your little chunk of bone
-你然后拿切的
that you’ve removed, and you drop it into resin.
小块骨头放进树脂
And then this needs to cure for several days.
它需要几天来固化
I mean, can you imagine playing Dungeons and Dragons
我想说 你能想象用恐龙骰子
with dinosaur dice? -Dungeons and Dinosaurs?
玩《龙与地下城》吗 -《龙与地下城》?
-Oh!
哦!
Exactly.
正是
-Then you glue your D6 to a microscope slide
-接着你把骰子和载物片粘合
and slice it down even more.
再进一步切片
I did a terrible job with the saw.
我用锯子犯了大错
I almost destroyed everything with the saw, actually.
我几乎损毁了全部标本
I feel like I’m pushing too hard.
我觉得我已经尽力了
-OK.
-停
[yelps]
[惊叫]
I did it.
弄好了
-At this point, it’s too small to slice,
-此时 标本小得不能切
so Akiko will grind away extra layers.
所以Akiko将磨掉多余的层面
这圈是钻石沙 这里就是打磨用的一面
你稍微带上来一下 一点一点来 最后你就会开始听到噪声
We’re listening for that “shoog-shoog” sound.
我们在听“嘘-嘘”声
[shoog-shooging]
[磨片的“嘘嘘”声]
The slide ultimately needs to be between
最终切片厚度需要
30 and 80 microns thick —
在30到80微米之间
thinner than a sheet of paper.
比一张纸还薄
Akiko basically uses finer and finer grinders,
Akiko其实在用越来越精细的研磨机
like varying grades of sandpaper,
就像不同级别的砂纸
to slowly shave off extra layers.
以此慢慢磨掉多余的层
-Straight down. That’s the key.
-下一步是关键
– I will try my best. – Yeah, I’ll show you.
-我会尽力 -好 我会教你
-You scared me now, though.
-你吓着我了
There’s a polishing stage to smooth out
这是抛光阶段
any major imperfections that might obstruct the sample.
抚平任何会影响显微镜观察的严重瑕疵
You’re not getting away from me!
帮我 别离我太远
And a second polish for fine tuning.
第二次抛光是为了精调
This one feels like someone is
做这个我感觉就像有人
pulling carpet out from underneath the block.
这个方块下扯垫子
Even with your naked eye, you can learn about a specimen.
就算是用肉眼 你也能分辨标本
Here’s a piece of Sue’s rib,
这片是Sue的肋骨
and you can see how Sue grew almost like rings on a tree.
你能像看年轮一样 观察Sue怎么成长
You see these faint lines?
看见细微的线条了吗?
Yeah.
看到了
– Yeah, it’ll be much – It looks like agate.
-对 它会更 -看着像玛瑙
-Yeah, it’ll be much clearer
-放在显微镜下时
once we get it under a microscope,
线条会更清晰
but those are the lines of arrested growth.
但这些线条表示生长停滞
Do you want to look in?
你想往里看看吗?
Yeah I will look in
好 我会看的
-And here we’re looking into the rib of Sue the T. rex.
我们现在观察Sue的肋骨
You notice that the space between these lines of growth
你会看到这些生长线之间
is becoming smaller and smaller.
空隙变得越来越小
So when it was younger and really having to bulk up, right,
当它更年轻时 不得不快速长大 是吧
it was growing very quickly.
它长得特别快
And as it reaches adult size, growth slows down.
长到成年体格时 生长速度就变慢
-The thinness of these sections was surprising
这些线条很稀疏 真令人惊讶
because it shows a fast growth rate,
因为这代表着生长速率很快
a key indicator that Sue had a high metabolic rate,
而高生长速率是Sue具有高代谢率的关键指标
meaning she was probably not as cold-blooded
意味着它可能不是科学家
as scientists previously thought.
之前所认为的冷血动物
Scientists also looked at another indicator
科学家同时也关注高代谢率的
of high metabolism, which is actually color.
另一个特征 即颜色
More diverse colors in a species
在一个物种中 更缤纷的色彩
tends to mean a higher metabolism.
通常意味着更高的代谢率
-Here, we are looking at an SEM image of a sample from a feather
-我们正在观察一片羽毛样本的扫描电镜图
of a 130-million-year-old bird called Eoconfuciusornis.
羽毛来自1.3亿年前的始孔子鸟属
Pre-extinction.
在Sue之前灭绝
-So the only fossil bird
-所以唯一要比
older than this fossil bird is Archaeopteryx.
始孔子鸟化石更早的 是始祖鸟化石
-A scanning electron microscope relies on
-扫描式电子显微镜不依赖光
electrons instead of light to magnify even more detail.
而依赖电子 能放大更多的细节
-And so if you look closely, you’ll see this-
-所以如果你仔细观察 会看到这个
this is literally what we call them-
我们通常叫这个
sausage-looking structures.
香肠状结构
[Abby laughs]
[Abby笑声]
They are eumelanosomes.
这些是真黑色素
So eumelanosomes are responsible for the color black.
真黑色素会产生黑色
-Melanosomes are organelles found in animal cells
-黑素体是在动物细胞中发现的细胞器
that are associated with different colors.
与不同的颜色有关
When they fossilize, they leave behind distinct shapes.
当它们成为化石 会形成完全不同的形状
-If they’re very nicely aligned with each other,
-如果两者完美地互相叠加在一起
we can tell it’s iridescent black.
我们能看出闪亮的黑色
If they’re kind of a more oval-shaped eumelanosomes,
如果真黑色素更偏椭圆形些
that’s gray, and then if it’s a phaeomelanosome,
就成了灰色 如果是褐黑色素
we call these ones meatballs.
它们就是肉丸形状
Literally, this is like, in papers, they’re like, -Such a delicious science.
字面上 这就像 论文中也这么描述 就像 -科学听起来真好吃
“the meatball-shaped ones.”
“肉丸状的东西”
[Laugher] mm, I’m hungry.
[笑] 额 我饿了
The meatball-shaped phaeomelanosomes are responsible for a rusty red color.
肉丸型的褐黑色素会产生铁锈红的颜色
-Many of the genes responsible for melanosomes
-许多与黑素体相关的基因
are also linked to things that affect metabolism,
也与影响代谢率的物质有关
so evolving one most likely evolves the other.
所以一方有了 另一方必定存在
And with both meatballs and sausages,
肉丸和腊肠结合在一起
Eoconfuciusornis shows way more melanosome size diversity
始孔子鸟化石比今天的类蜥蜴爬行冷血动物
than modern-day cold-blooded lizards.
具有更多变的尺寸
-So we can say that the dinosaurs
-所以我们能说恐龙
that are becoming smaller, that are getting
变得更小 变得能发育出
these large extravagant ornamental structures
这些庞大 精美且富有装饰性的结构
that are then able to evolve flight
因此能进化出双翼
are also becoming more colorful.
恐龙也变得更加色彩斑斓
-But these melanosomes can only tell us so much.
-但这些黑素体也只能告诉我们这么多
They’re an indicator of warm-bloodedness, but not definitive proof.
它们是恒温动物的指标 但不能完全证明
This is where Jasmina comes in.
而Jasnina也研究这难题
-Everything that Jasmina is doing, five years ago that didn’t exist.
-Jasmina做的 全是五年前还不存在的研究
I’m a molecular paleobiologist.
我是一名分子古生物学家
My passion lies within the clade of dinosaurs including modern birds.
我的研究兴趣是恐龙(包括现代鸟类)的进化枝
People tend to think of bones and shells
人们更倾向于想到
and these kind of heart tissues
更易于保存的
that preserve much more readily.
这种骨头 外壳和心脏组织
But if we want to get a complete picture
但如果我们想要完整地认识
about the diversity of life on our planet,
地球的生物多样性
we really depend on soft-tissue preservation.
我们真得依赖于软组织的保存
-Soft tissue is the squishy stuff like skin,
-软组织就是湿软的东西
blood vessels, and other non-bony materials
像肌肤 血管 其他非骨质材料
that scientists didn’t even think could preserve until recently.
科学家甚至不认为它们能被保留到现在
So, about 30 years ago,
因此 大概三十年前
a vertebrate paleontologist tried for the first time
一位古脊椎动物学家第一次尝试
to extract soft tissues from dinosaur heart tissues.
从恐龙心脏组织中提取软组织
-Her name is Mary Schweitzer, and people did not believe her findings.
-她叫玛丽·史怀哲 人们质疑她的发现
It was very critically perceived, and people thought for a long time
对她的发现批评挑刺 很久以来 人们认为
that while these soft-tissue structures
虽然这些软组织结构
very much looked like the original biological structures,
与原始生物的结构非常相似
they could not possibly be related.
但它们之间也不可能有联系
-But soft tissues do preserve.
但软组织的确保留了下来
Why do they preserve?
为什么会保留下来了呢?
This is absolutely paradoxical
基于当时所谓的科学认知
based on what was known scientifically at that point in time
这完全是自相矛盾
-You can actually see traces of it under a UV light.
-在紫外线下 你能看到软组织的痕迹
-What we’re going to do is just shine the light and look for things.
-我们只需要打开灯光 并找到一些痕迹
It looks like some of these may be scales
其中一些看起来可能是鳞屑
that are preserving soft tissue.
鳞屑是保留下来的软组织
Not all of them.
不是全部
-Once soft tissues are suspected,
-一旦有软组织的迹象
demineralization will isolate them if they’re present,
那么若它们出现 脱矿作用就使其分离
so you can see the structures.
于是你就能观察结构了
This is where I got to try something with Sue’s bones
至此 我要用Sue的骨头做个实验
that has never been done before.
这从未被前人尝试
So, you mentioned that you would like to dissolve a Sue fragment
所以你是说你想要溶解Sue的一块碎片
and help us look for organics.
并帮我们一起找有机物
Every bone is going to have the tissues that we’re looking for
假设骨头确实保存了下来
if they are in fact preserved.
那其中的每一块都可能有我们需要的组织
But Sue has exceptional preservation,
但Sue保留了独特的物质
so we are quite hopeful.
所以我们很有希望
-We’re taking this bit of Sue
-我们打算拿这块碎片
and dissolving it in hydrochloric acid.
用盐酸溶解
The acid will dissolve any inorganic rock
这个盐酸可以溶解任何无机质岩石
but leave behind the organic soft tissues.
但会留下有机软组织
It’s starting to look like a hazy IPA.
开始看着像浑浊的间苯二甲酸液
– Are you seeing anything?
– 看见什么了吗?
-It’s all still in suspension.
-都还处于悬浮状态
-Me too. -We’ll have to give it a little bit of time.
-我看到了 -我们得给它点时间
-After about 15 minutes, the precipitate settles
-约15分钟后 颗粒沉淀下来
and Jasmina pipettes it onto a slide.
Jasmina用移液器吸取到载物片上
-From here we go to the microscope.
-我们从这儿拿到显微镜那儿
-Let’s go.
-走吧
-Ooh, this is looking good.
-哇哦 看起来很棒
-What are you seeing?
-你看见了什么?
-We have a couple of
-这里有几个
extracellular matrix pieces,
细胞外基质块
blood vessels, large blood vessel fragments.
血管及其大块碎片
-You are the first person to see
-你是第一个看见
a bit of Sue’s blood vessels.
Sue的一块血管的人
-Yes.
-对
I was the second person
我是第二个
to see Sue the T. rex’s veins.
看见暴龙Sue血管的人
Right now, take a look.
就现在 我看看
-OK.
-好的
-Do you see the blood vessel structures?
-你看见这个血管结构了吗
right in the focus center?
就在这个中心焦点
– It’s this hollow branching shape. -Yes, yeah!
-就是这个空心的 有分支形状的 -看见了!
-That is definitely one of the bone vascular canals.
-确切的说那是 一个骨血管
-Oh, I see it real good now.
-哦 我现在很清晰地看到了
Hold on.
等一下
They’ve just been in there the whole time!
它们从古到今一直存在
-They’ve been sitting there for 65 million years. -Just floating around.
-它们已经呆在这儿6500万年了 -一直四处漂浮
[Laugher]
[笑]
That was rad.
真是激动人心
Because we can look at this
因为我们在这里见证了
of course fascinated by the fact that,
毫无疑问 这个令人着迷的事实
you know, soft tissues preserve in the time,
也就是 软组织保留到了现在
but there’s actually a lot of information
我们能从中挖掘很多
in the molecular composition of these materials -Yeah, what can we see?
这些物质分子构成的信息 -对 能看见什么呢
Demineralization shows us that
脱矿作用让我们看见
there are soft tissues present in a specimen,
样本中的确存在软组织
including the proteins, lipids,
包括能表现高代谢率的
and sugars that indicate a high metabolism.
蛋白质 脂质 糖分
But to concretely say, what soft tissues are present
但具体来说 为了搞明白出现了什么软组织
and prove that this vein is really a vein
也为了证明这些发现的结构确实是血管
and that these metabolic stress markers are actually here,
以及高代谢应激的标志物确实就在这儿
we need to study the chemicals found in the tissues.
我们就需要研究在这个组织里发现的化学物
This requires a brand-new method:
这需要使用一个全新的方案:
an application of Raman spectroscopy
也就是由Jasmina及其团队
developed by Jasmina and her team.
研发的拉曼光谱法
-It’s the brightest, purest green
-这将是你见到的
that you will ever see.
最亮 最纯粹的绿
Yeah, why the green light?
-为什么用绿光
-We’re using a green light that is exactly 532 nanometers.
-我们使用刚好532纳米的绿光
That is particularly good for characterizing organics
这种光 能很好地帮助我们表征
with many unsaturated carbon bonds.
有许多不饱和碳键的有机物
-It’s a nondestructive technique,
-这是一项无损测试的技术
so you can stick entire specimens under the laser
因此你可以把整个标本放到激光下
without having to prepare them at all.
完全不需要做前处理
We popped in a piece of Sue taken from her femur core.
我们从Sue的股骨中取出了一部分
-I want to make sure that we’re looking at a spot
-我要确定我们所观察的地方
where we don’t have too much surface texture,
没有太多表面纹理
where we have a lot of carbonaceous material preserved.
保留有很多含碳物质
-The laser excites the different materials in the sample.
-激光激发了样本里不同的物质
And so these chemical bonds, they start to vibrate
所以这些化学键开始振动
in direct response to their chemical environment.
对所在的化学环境直接产生响应
And these very specific little wiggles
于是这些特殊的小波动
are then detected in form of a spectrum.
就以光谱的形式被我们检测到
Now, if we want to, for example,
比如 若我们现在想要
learn something about the metabolic rate of Sue,
了解Sue的代谢率
we collect the spectrum for Sue
我们收集Sue和其他
and for all other kinds of dinosaurs that have this mode of preservation.
软组织保存方式相同的恐龙
I can show you basically what it looks like
我可以给你展示我们大体是怎样
when you compare these different spectra.
比较这些不同的光谱的
-This is Sue’s Raman data
-这是Sue的拉曼光谱数据
compared to data Jasmina got from other dinos.
与Jasmina从其他恐龙上得到的数据相比
-So every individual line basically represents
-所以基本上每条线都代表
evidence of the total composition
我们观察的每个化石
of one of the fossils we’ve looked at.
其整个构成成分的存在迹象
-So these numbers are sort of different wiggles.
-这些数字代表着不同的波动
-Yes.
-对
-So you get a different wiggle
所以你从这些不同的波动中
at each of these different wave numbers,
观察到不一样的波动
and that then evidence it’s
从而证明是
a different kind of molecular bond vibration.
不同的分子键振动
-So a different kind of chemical compound present in the sample.
-所以不同种类的化合物会出现在样本中
-Different compounds tell us different things
-不同的化合物告诉我们
about the dinosaur we’re looking at.
所研究恐龙的不同信息
For example, thioethers,
比如 此软组织中的硫醚键
sulfur heterocycles, and nitrogen heterocycles
含硫杂环 含氮杂环
in the soft tissues signal high metabolic stress.
标志着高水平的代谢应激
We have very high amounts
我们在恒温动物体内
of these metabolic stress markers in warm-blooded animals,
观察到了大量高代谢应激的标志物
and we have very low amounts
而在冷血动物体内
of these metabolic stress markers in cold-blooded animals.
看到的高代谢应激的标记物却很少
This peak here in combination with this peak here
这边的峰 加上这边的峰
and this one here tells us if we’re looking
再加这个 告诉了我们
at a warm-blooded or a cold-blooded extinct animal.
正在看的是恒温还是冷血的已灭绝动物
-This wiggle here is proof
-这一个波动证明了
that Sue the T. rex was truly warm-blooded.
暴龙Sue其实是恒温动物
And it once again changes the story of evolution
这项发现再次改写了
that scientists have been telling
古生物学研究初期时
and retelling since the early days of paleontology.
科学家反复强调的所谓进化史
It has been suggested that the high metabolism of birds
这个发现说明鸟类的高代谢率
eventually helped them to better adapt
最终帮助它们更好地适应
to the changing environments, the changing conditions
生物集群灭绝事件发生之后
right after the mass-extinction event.
变化的环境和生活条件
What we basically realized here once we start putting
当我们根据现实考虑这些新的生理数据
these new physiological data into context
我们其实会意识到
is that this incredibly high avian metabolism
这个极高的禽类代谢率
is actually not an avian innovation.
其实不是禽类的创新
-It’s not just Sue either.
-也不是Sue发展出的
Jasmina’s work has definitively found
Jasmina的研究最终发现
that most dinos were warm-blooded,
大多数恐龙是恒温动物
practically upending what was once common knowledge.
几乎颠覆了曾经被公认的所谓常识
I have been coming to the Field Museum
我从儿时开始
since I was a little kid.
就常常参观菲尔德博物馆
Oh, the Tully monster!
哇 怪物塔利!
This is my favorite fossil!
这是我最喜欢的化石
I won’t get distracted.
我不会被分心的
Being able to come to the Field Museum
能够来到菲尔德博物馆
and see how the Field Museum works
并且看到博物馆研究工作是怎样做的
was like a dream come true for tiny paleontologist Abby.
对我这个古生物学发烧友来说 像是梦想成真
The Abby-roll.
Abby人员名单
-Got ’em.
-没问题
-I cannot do inches. I’m European.
-我分不清英尺 我是欧洲人
[Abby laughs]
[Abby笑声]

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视频概述

随着相关领域研究的进步,人们发现研究恐龙化石中的软组织能够揭示大量恐龙细胞的惊人细节信息。在重建恐龙时,骨头通常是我们剩下的全部工作,但偶尔科学家会很幸运地找到更多的东西。像羽毛、皮肤、蛋、甚至大脑,这些则都可以揭示对这些神奇动物的新认识。 自从古生物学诞生以来,科学家们一直在激烈地争论恐龙是内温动物(简介中的恒温动物)还是外温动物(即常说的冷血动物)。人们普遍认为,温血动物是禽类的创新,是鸟类发展出来的,而它们的古恐龙亲戚如霸王龙Sue却没有。传统的方法和工具,如组织学和扫描电子显微镜,已经暗示

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视频来源

https://www.youtube.com/watch?v=nBqd_V418Kg

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