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腹毛动物门:四天高龄的祖母 – 译学馆
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腹毛动物门:四天高龄的祖母

Gastrotrichs: Four Day Old Grandmothers

《微观旅途》
It takes a long time to make a human.
造就一个人需要很长时间
We can sometimes, I think,
我认为有时候
get caught up in our own perceptions of how life works.
我们会局限于以自己的视角来看待生命的运作
But there are some organisms
但有些生物
that don’t have the luxury of years and years of childhood.
它们没有这份奢侈——年复一年的幼年期
No, for them, life is brief
对他们来讲 生命是简单的
and they’ve got to get on with living…
必须生存下去……
and so sometimes like with the gastrotrich,
有时候 比如像腹毛动物
they’ll just go ahead
它们只能匆忙向前
and have their first baby on the day they’re born.
在出生当天就产下第一个后代
Now we’ve never had the chance to name a species of microbe.
如今我们再也没有机会去命名微生物的某个物种了
We name individuals all the time,
我们总是给个体取名
this one’s Neil.
这一个叫Neil
But naming a species
但是给一个物种命名
seems like both a thrilling and weighty task.
似乎是一项既刺激又沉重的任务
You take this strange, new, tiny thing,
你把这个奇怪 陌生的小东西
and you assign it an identity that it will never know
赋予一个它自己永远不会知道
but that other human observers will come to rely on,
但其他人类观察者会依赖于此的名字
ostensibly forever.
看来会一直用下去
And through the years, people who have faced this challenge
多年来 面临这一挑战的人们
have turned to a wealth of imagery and language to guide them.
从比喻和语言文字的宝库中寻求指导
There’s the multi-headed serpent of Greek and Roman mythology,
“海德拉”——希腊和罗马神话中的多头蛇
now also the name
它有着神奇的再生能力
for the multi-cellular, regenerating wonder of Hydras.
它如今也是这种多细胞生物水螅的名字
Or you could go cuter,
或者可以用更可爱的名字
like the tardigrade, which translates roughly to “slow stepper”
比如 缓步类动物 大致就是“走路缓慢者”的意思
which also has the advantage of being accurate.
这也具有更为准确的优点
And then, you have Gastrotrichs,
接下去 腹毛动物出场了
also known by their phylum name Gastrotricha.
它也以腹毛动物门这个词为人所知
These organisms were not named in so flattering a fashion.
这些生物的名字并不那么讨喜
No, Gastrostricha translates to “hairy stomachs.”
腹毛翻译过来就是“长毛的胃”
And when you don’t feel like saying “gastrotrich,”
当你不想说“腹毛”的时候
you can also call them by their common name: “hairy backs.”
也可以用通用名“长毛的背部”来称呼它们
But a rose is a rose by any other name,
不过不管叫什么名字 玫瑰还是玫瑰
and, truth is, they do have hairy stomachs. And backs.
事实就是 它们的胃和背部确实有毛
All, as we will see, for good reason.
我们将会看到 有毛是有充分理由的
But if their name doesn’t capture the mythological glory
如果说它们的名字没有像其他生物那样
that other organisms get,
披有神话的荣光
there are moments, when the light hits just right
但有些时候 当光线照射角度刚好
and bounces off their little scales,
它们的小鳞片反着光
that Gastrotrichs resemble iterations of
那样的腹毛动物竟有点类似
one of the most pervasive mythological figures of all time:
有史以来最广为流传的 反复出现的神话形象之一
the dragon.

We should scale back a bit though.
我们把放大倍数缩小一点
After all, gastrotrichs are among some of the smallest metazoans,
毕竟 腹毛动物属于最小的多细胞动物之一
or we could say, less esoterically…animals.
或者我们可以说 不那么复杂的……动物
They range from around 60-500 micrometers long,
它们的长度在60-500微米之间
though in some very exceptional cases,
不过在一些非常特殊的情况下
they might get up to several millimeters in length.
它们的长度可能达到几毫米
There are two orders in the Gastrotricha phylum:
腹毛动物门有两个目:
Chaetonida, which are mostly found in freshwater,
鼬虫目 主要存在于淡水中
and Macrodasyida, which are found in marine systems,
还有大鼬目 存在于海水中
though there are, weirdly, a few freshwater species.
不过也有一些奇特的淡水种
No matter what order they belong to,
不管它们属于哪个目
they make up part of what’s called the meiofauna.
它们构成了所谓的较小型底栖生物的一部分
These are species grouped by their size.
它们是按照大小分组的物种
Too big to be microfauna,
说它是微型动物则太大
too small to be macrofauna,
说它是大型动物又太小
the meiofaunal organisms are between 60 micrometers to 2 millimeters
较小型底栖生物在60微米至2毫米之间
—and they play a deeply important ecological role,
它们在生态系统中扮演着非常重要的角色
a bridge between the micro and the macro,
是微型和大型生物之间的过渡
consuming the former and being consumed by the latter.
以前者为食 又被后者吃掉
They are a part of this system
它们是这个系统的一部分
that brings nutrients out from the microscopic world,
把营养物质从微观世界
into the parts of ecosystems that we can directly observe.
带到我们可以直接观察到的生态系统中
Gastrotrichs are among the most abundant species present in the meiofauna.
腹毛动物是较小型底栖生物中数量最多的物种之一
In some habitats,
在一些栖息地
it’s been estimated that there are around 100,000 individual gastrotrichs per square meter.
据估计每平方米大约有100000个腹毛动物
And there are around 860 known species counted across both orders.
这两个目总共有约860种已知物种
Now, that’s a lot of species of Gastrotrichs,
你看 腹毛动物有很多种吧
but it’s actually surprisingly low
但事实上 与其他较小型底栖生物的多样性相比
compared to the diversity of other meiofaunal organisms.
它的数量少得惊人
There are, for example,
比如说
over 2,000 rotifer species,
轮虫有2000多种
and approximately 40,000 species of nematode.
线虫大约有40000种
Now this doesn’t mean anything bad for gastrotrichs
这对腹毛动物而言并不意味着坏事
—though it might be why they have yet to be found in any extreme kind of habitat.
不过这可能是未曾在极端的栖息地发现它们的原因
But it is remarkable that for microscopic metazoans,
但值得一提 就微小的多细胞动物而言
860 species is low when you put it up against some other phyla.
与其他一些门相比 860个种算是少的
Returning to their unfortunate but well-earned name:
回到它们那个不幸却又实至名归的名字
the stomachs of gastrotrichs are covered in hair-like cilia,
腹毛动物的腹部覆盖着毛状纤毛
which they use to glide along surfaces
当它们进食细菌 藻类和其他小颗粒时
as they dine on bacteria, algae, and other small particles.
可以通过纤毛沿着它们的表面游动
Unfortunately for us, it is hard to observe and film these hairy stomachs
不幸的是 我们很难观察和拍摄这些长毛的腹部
because, well, they swim with their bellies down
因为它们游动时腹部朝下
We’ve found that when we record gastrotrichs, we have to be extra careful.
我们发现 记录腹毛动物时必须格外小心
Their head is covered in cilia and mechanoreceptors
它们的头部覆盖着纤毛和机械感受器
that seem to respond to any slight movement in the water.
它们似乎对水中任何细小的运动都有反应
So it’s important
所以这点很重要
not to create any accidental vibrations in the microscope
不要在显微镜中产生任何意外振动
that might startle them.
以免可能惊吓到它们
Gastrotrich bodies are enclosed in a cuticle
腹毛动物的身体有角质层包裹
and covered in spines or scales, or sometimes both.
表面覆盖着棘刺或鳞片 有时两者都有
And at the end of their bodies, many species have a pair of feet,
在它们身体的末端 许多物种都有脚
which hold adhesive tubes
脚上有吸附管
that they can use to attach to grains of sand or other objects.
可以通过它吸附在沙粒或其他物体上
And underneath the hairy, scaly cuticle,
在毛鳞片状的角质层下面
we see the wonder of a multicellular body:
我们见识到了多细胞体的奇迹
a brain, nervous system, simple gut, intestines, muscles, and more.
有大脑 神经系统 简单的胃 肠 肌肉等等
Inside of this chaetonid gastrotrich is an egg,
这个腹毛动物的内部是一个卵
and when that egg hatches,
当卵被孵化后
out will come a new gastrotrich, fully developed with all of those organs in place,
就会产出一个各器官已充分发育的新的腹毛动物
and about 2/3 the length of a full adult.
大约是成年体三分之二的长度
The fact that it hatches so formed is remarkable on its own,
这种自体孵化方式非常引人注目
but the whole reproductive cycle of chaetonids is a marvel
鼬虫的整个繁殖周期堪称奇迹
Gastrotrichs are not particularly long-living creatures.
腹毛动物并不是特别长寿的动物
Their life span is on the order of days to weeks,
它们的寿命大约是几天到几周
which means
这意味着
they have to cram a lot of living into a short amount of time.
它们不得不把许多生命活动塞进短短的一生
When they hatch,
当鼬虫孵化时
chaetonids seem to immediately begin developing their eggs through parthenogenesis,
它们似乎立即开始通过孤雌生殖发育卵
a kind of cloning
这是一种克隆
through which an unfertilized egg
未受精的卵子通过这种方式
is able to develop into an embryo that is genetically the same as the parent.
可以发育成与母体基因相同的胚胎
In the species and conditions that chaetonid reproduction has been most extensively documented in,
在大量对鼬虫繁殖的种类和条件的记载中
you might see a gastrotrich lay an egg within a day after they themselves hatch.
你可能会看到腹毛动物在自己出生后一天就产卵
And typically, they’ll lay 4 eggs within 4 days
一般情况下 它们会在4天内产下4枚卵
that can develop and hatch within a day of being laid,
这些卵在被产下后的一天内就能发育和孵化
producing genetically identical offspring.
产生基因相同的后代
And those children are then out there themselves laying eggs,
然后那些后代又可以自己产卵
meaning a gastrotrich can become a grandmother just a few days after it was born!
这意味着腹毛动物出生后几天就能成为祖母!
And here’s another weird thing…
还有另一件怪事
sometimes, they lay a special kind of egg called an opsiblastic egg,
有时 它们会产下一种特殊的卵 称为晚期卵
which has spines and is thicker and larger compared to the other eggs,
与其他卵相比 它有棘刺 并且更厚更大
qualities that keep it protected under harsher conditions.
这些特点能让它抵御恶劣的条件
Because of this rapid egg laying,
由于这种快速产卵
we used to think that chaetonids were entirely made up of parthenogenetic females.
我们曾经以为鼬虫完全由孤雌生殖雌性组成
But later observations have revealed
但是后来的观察发现
that once these early eggs get laid,
一旦产下这些早期的卵
the chaetonids become hermaphroditic, developing sperm and eggs.
鼬虫会变成雌雄同体 产生精子和卵子
What they use the sperm for though is a mystery.
但它们的精子有何用仍然是个谜
We just don’t have the observations we need
我们尚未得到必要的观察资料
to understand how chaetonids make use of their hermaphroditic phase.
去了解鼬虫如何利用它们的雌雄同体阶段
This life history though characterizes just the chaetonids.
不过 这一生活阶段只是鼬虫目的特征
Macrodasyoid gastrotrichs seem to all be hermaphroditic except for one species,
对于大鼬目 除了一个物种 似乎都是雌雄同体的
and so their process is of course different.
所以它们的生殖过程当然是不同的
And yet the result is the same:
但结果是相同的
the direct development of young gastrotrichs
腹毛动物幼体的直接发育
that contain the full multicellular plan in their own body,
其体内带有完整的多细胞生物发育计划
ready to create the next generation at birth.
出生时就做好了孕育下一代的准备
It’s hard to know sometimes
当你观察微观世界的时候
what to be most impressed by when you’re looking into the microcosmos.
有时很难知道什么会给你留下最深刻的印象
Is it the giant unicellular organism,
是巨大的单细胞生物
or the tiny multicellular one?
还是微小的多细胞生物?
Is it giving birth on the day you were born,
是出生当天就产下后代
or the 40,000 species of nematodes..
还是40000种线虫……
of course, chances are,
当然 很有可能
just minutes ago
就在几分钟前
you had no idea that the earth was covered in these tiny beasts,
你还不知道地球上覆盖着这些微小的动物
bridging the words of the micro and macro,
它们架起了微型和大型两词之间的桥梁
and now we can’t even decide what the coolest thing about them is.
我们甚至说不清它们最酷的地方是什么
Complexity is its own complex thing,
复杂性本身就是一个复杂的东西
so carry on, our hairy-bellied friend.
所以继续前行吧 我们的毛茸茸肚皮朋友
And thank you for coming on this journey with us as we explore the unseen world that surrounds us.
感谢你与我们一起踏上这趟探索周围未知世界的旅程
And thank you especially to all of the people on the screen right now
特别感谢现在屏幕上
who support us via Patreon.
通过Patreon赞助我们的所有人
These people allow us to continue diving into these mysteries.
是他们让我们得以继续探究这些谜团
It’s a joy to do
这是件愉快的事
and we’re so happy that you are compelled to help us out.
我们很高兴 你给我们提供了必要的帮助
If you want to see more from our Master of Microscopes, James,
如果你想看更多《显微镜大师詹姆斯》的节目
you can check him out on Jam and Germs.
请关注Jam and Germs
And if you want to see more from us,
如果你想看更多我们的节目
here at Journey to the Microcosmos,
请关注《微观旅途》
you can find us on twitter at twitter.com/journeytomicro
可以在推特找到我们 twitter.com/journeytomicro
and you can also find us here on youtube at youtube.com/microcosmos.
也可以在youtube找到我们 youtube.com/microcosmos

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视频概述

名字不讨喜的腹毛动物 是生态系统的重要一环

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视频来源

https://www.youtube.com/watch?v=wje4W2XiZus

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