未登录,请登录后再发表信息
最新评论 (0)
播放视频

蛋壳显示恐龙或不是冷血动物

Dinosaurs Probably Weren't Cold-Blooded, According to Eggshells

Sometimes in science
有时在科学领域
the answer just isn’t where you thought it was gonna be
答案并非你想的那样
and last week in the journal Science Advances an international group
上周 一个国际研究小组在《科学进步》期刊上
of researchers published insight into an age-old problem
发表了他们对一个老问题的看法
from a pretty surprising place
其研究对象令人惊讶
They analyzed dinosaur eggs to get an idea of the mother dinosaurs‘ body temperature
为了解恐龙蛋形成时恐龙妈妈的体温
when the egg was formed
他们分析了恐龙蛋
and the results are giving us a much clearer picture
研究结果使我们更清楚地知道
of how dinosaurs evolved from cold blooded reptiles to warm-blooded birds.
恐龙是如何从冷血爬行动物进化成温血鸟类的
Warm-bloodedness aka endothermy
温血也就是恒温状态
is a huge part of how birds and mammals
鸟类和哺乳动物遍布全球
have been able to spread all across the world
很大一部分是因为它们是恒温动物
it seems to have evolved separately in each group
每一个种群似乎都是单独进化的
but the result is the same
但结果是一样的
instead of relying on the sun’s warmth to maintain our body temperatures
我们不依赖太阳的温度来保持体温
we have the freedom to live in a whole range of climates
可以自由地生活在各种气候中
and keep up fairly consistent energy levels at the same time
同时保持相当稳定的能量水平
many researchers are pretty sure that
许多研究人员坚信
birds warm-bloodedness evolved in their dinosaur ancestors
鸟类的恒温性是从它们的恐龙祖先进化而来的
but for a long time
但很长一段时间以来
they’ve been trying to figure out exactly how
他们一直试图弄清楚这是何时发生的
and when that happened
又是如何发生的
these days a lot of researchers argue
最近有许多研究人员认为
that many dinosaurs were mesotherms
很多恐龙都是中温动物
basically somewhere in between warm and cold blooded
大致介于恒温动物和冷血动物之间
Like endotherms,
像恒温动物一样
mesotherms burn energy to produce heat
中温动物消耗体内能量来产生热量
that raises their body temperature.
从而使体温升高
now we endotherms maintain our body temperatures
作为恒温动物 我们人类的体温
at a set point about 37 degrees in humans
维持在一个约37摄氏度的固定值
but living mesotherms don’t have a thermostat
但中温动物体内没有“恒温器”
they just kind of turn on the heat and hope for the best
它们只是稍微开了些暖气 希望一切都暖和起来
To learn more about how temperature regulation might have evolved in dinosaurs,
为了进一步了解恐龙体温调节是如何进化的
it’s important to know what their internal temperatures were
很重要的一点是要知道恐龙体内的温度
if they were warmer than the weather outside
如果恐龙的体温高于外界温度
that points to at least some control over their body temperatures
那至少说明它们可以在一定程度上控制体温
Previous research on this has involved
早前在研究恐龙体温的时候
looking at different dinosaurs growth rates
根据恐龙骨骼上有点像树木年轮的印记
which you can calculate based on marks left in their bones
人们算出了不同种类恐龙的生长速度
kind of like tree rings
并且对此进行了研究
Cold-blooded reptiles with their slow metabolism
新陈代谢缓慢的冷血爬行动物
tend to grow slowly,
往往生长速度也很慢
while warm-blooded animals tend to have much higher energy levels
而恒温动物能量水平更高
and therefore it grow more quickly
所以它们生长速度更快
The problem is the relationship between growth rate and metabolism isn’t always that simple
但是 生长速度和新陈代谢之间的关系复杂
which means looking at how dinosaurs grew might not be
也就是说 研究恐龙的生长速度
the most reliable way to figure out if they had control over their body temperatures.
也许不是弄清它们能否控制体温的最可靠办法
So the authors of this new paper used a different technique
所以这篇论文的作者们采用了另一种
one that’s only come into use relatively recently
人们最近才开始使用的方法
it’s called clumped isotope paleo thermometry
它叫块状同位素古测温法
The paleo thermometry part just means measuring temperature
古温测定部分是指测量动物的体温
in animals usually extinct ones
通常是灭绝动物的体温
it’s the clumped isotope part of the name
而名称中的块状同位素
that really describes what the technique is.
才真正说明了该技术到底是什么
Isotopes are basically versions of the same element with different weights
说穿了 同位素就是同一元素不同质量的原子
some are more common than others
同一元素中 有的同位素会相对常见些
and their abundances can vary based on a variety of factors
同位素的丰度会随着各种因素发生变化
so when the rarer isotopes clump together within groups of molecules
所以 当相对少见的同位素在数组分子中聚集
that can tell you a lot about how they got together
你能具体得知 它们聚集的方式
and what the conditions were like when those molecules formed,
和这些分子形成时的条件
like what the temperature was.
比如它们形成时的温度
In the past some researchers
过去一些研究人员
have used the clumped isotope technique on dinosaur egg shells
在恐龙蛋壳上使用过块状同位素技术
which allowed them to calculate the temperature
她们借此计算出了恐龙蛋形成的时候
inside the dinosaur when the egg was formed
恐龙体内的温度
but as the authors of this paper pointed out the problem is
但是 正如这篇论文作者所指出的
that they’ve only done that for dinosaurs that lived in warm climates
问题是 他们只研究了那些生活在温暖气候中的恐龙
which means it wouldn’t matter if they were endothermic
这意味着 假设恐龙是恒温动物 或者
or mesothermal or whatever
假设恐龙是中温动物之类的 都没有太大意义
because their temperature would have been close
因为它们的体温无论如何
to that of their warm surroundings no matter what
都会接近周围环境的温度
When dinosaurs ruled the world from about 230
两亿三千万年前到6500万年前
million years ago to around 65 million years ago
恐龙一直称霸地球
earth was much warmer than it is today
那时候地球的温度比现在要高很多
There were still some places with average temperatures below 30 degrees or so
不过也有一些地方的平均气温低于30度左右
and some dinosaurs were adapted to live in those lower temperatures
某些恐龙为了在这样较低的气温中生活进行了进化
so the team applied the clumped isotope technique
因此 研究小组将块状同位素技术
to eggshells of dinosaurs
运用在了这类恐龙的蛋壳上
that lived in places with cooler climates mainly ancient Canada
这类恐龙生存的地方 温度相对不高 大多属于远古加拿大
They looked at three different species and in two of them the temperature
他们研究了三种不同类型的恐龙
inside the dinosaurs when these eggs formed
其中有两种恐龙在恐龙蛋形成的时候
was much warmer than the temperature outside would have been .
它们体温要远远高于外界温度
In fact at 36 degrees and 44 degrees both
实际上 36摄氏度和44摄氏度这两种体温
temperatures were in line with what we see in endotherms today
与今天恒温动物的体温是一致的
so these dinosaurs probably had some control over their body temperature
所以 这些恐龙可能在一定程度上控制自己的体温
Although it’s hard to tell
不过 从这些数据还是很难判断
from this data whether they mesotherms or endotherms
恐龙属于中温动物还是恒温动物
In the other species called Troodon formosus
在另一种叫伤齿龙的物种中
they actually found a range of body temperatures
研究人员们发现它们体温范围
from about 27 to 38 degrees Celsius
在27摄氏度到38摄氏度之间
that could be a sign that they were able to raise their body temperature
这个温度预示着它们能够增加自己的体温
but not necessarily control it
但并不一定能控制体温
which would indicate that at the very least they weren’t cold blooded
这也就是说 它们最起码不属于冷血动物
and may have been mesotherms
而且有可能是中温动物
So just from looking at the chemistry of eggshells
所以 仅仅研究蛋壳的化学成分
we now understand a lot more about
我们现在进一步了解了
how certain dinosaurs might have controlled their body temperature
某些恐龙有可能是可以控制体温的
And if future studies apply the technique to more species
如果 未来研究中在更多的物种上使用这项技术
we could get a lot closer to understanding how endothermy evolved over time
我们就能更进一步了解恒温动物的进化过程
which just goes to show what we can learn
这件事情 正好说明了 通过研究
from looking in some pretty unexpected places
意想不到的某些方面 我们能够学到什么
Thanks for watching this episode of SciShow
感谢观看这一期的《科学秀》
which was brought to you with the help of our amazing patrons
我们的节目由赞助者们出资制作
if you want to get involved and help us continue making videos
如果你想加入我们并帮助我们制作
about everything from dinosaur eggs to supernovas
从恐龙蛋到超新星内容无所不有的视频
check out patreon.com/scishow
登陆patreon.com/scishow

发表评论

译制信息
视频概述

我们如何知道恐龙是冷血动物还是恒温动物,你也许会在视频里找到答案哦。

听录译者

收集自网络

翻译译者

Spencer

审核员

审核员SR

视频来源

https://www.youtube.com/watch?v=9aZpd2BAUAk

相关推荐