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EmmaSchachner_2019X-_让恐龙称霸地球的秘密武器_-
We've all heard about how the dinosaurs died. 我们都听说过恐龙是如何灭绝的。
The story I'm going to tell you happened over 200 million years before the dinosaurs went extinct . 我接下来要讲的故事 发生在超过两亿年前 恐龙还未灭绝的时候。
extinct:adj.灭绝的,绝种的;熄灭的;vt.使熄灭;
This story starts at the very beginning, when dinosaurs were just getting their start. 这个故事要从头开始, 那时恐龙刚刚开始繁衍。
One of the biggest mysteries in evolutionary biology is why dinosaurs were so successful. 进化生物学最大的谜团之一 就是恐龙为什么那么成功。
evolutionary:adj.进化的;发展的;渐进的; biology:n.(一个地区全部的)生物;生物学;
What led to their global dominance for so many years? 它们如何在地球上称霸多年？
global:adj.全球的;总体的;球形的; dominance:n.优势;统治;支配;
When people think about why dinosaurs were so amazing, they usually think about the biggest or the smallest dinosaur, or who was the fastest, or who had the most feathers, the most ridiculous armor , spikes or teeth. 当人们感叹恐龙的神奇时, 他们通常会联想到 体型最大或最小的恐龙, 或是速度最快的, 或是羽翼最丰满的, 有着最奇异的铠甲,尖刺或利齿的。
ridiculous:adj.可笑的;荒谬的; armor:n.[军]装甲;盔甲;v.为…装甲; spikes:n.钉鞋(spike的复数);v.把…钉牢(spike的第三人称单数);
But perhaps the answer had to do with their internal anatomy -- a secret weapon, so to speak . 但是答案也许是它们的身体结构—— 这种所谓的秘密武器。
internal:n.内脏;本质;adj.内部的;里面的;体内的;(机构)内部的; anatomy:n.解剖;解剖学;剖析;解析; so to speak:可以说;打个譬喻说;
My colleagues and I, we think it was their lungs. 我和同事们都认为是它们的肺。
colleagues:n.同事;同行(colleague的复数);
I am both a paleontologist and a comparative anatomist , and I am interested in understanding how the specialized dinosaur lung helped them take over the planet. 我是一名古生物学家 也是一名比较解剖学家, 我十分想了解恐龙如何用 它们特殊的肺来称霸地球。
paleontologist:n.古生物学家;古生物学者; comparative:adj.比较的;相当的;n.比较级;对手; anatomist:n.解剖学家;剖析者; specialized:adj.专业的; v.专门研究(或从事); (specialize的过去式和过去分词) take over:接管;继承;接收;接任;接替;
So we are going to jump back over 200 million years to the Triassic period. 我们现在要倒退到两亿年前的 三叠纪时代。
The environment was extremely harsh , there were no flowering plants, so this means that there was no grass. 那里的环境十分严酷, 没有开花的植物, 也就意味着没有草。
extremely:adv.非常,极其;极端地; harsh:adj.严厉的;严酷的;刺耳的;粗糙的;刺目的;
So imagine a landscape filled with all pine trees and ferns . 想象一片只有松树和蕨类的土地。
landscape:n.景观;乡村风景画;(文件的)横向打印格式;v.对…做景观美化;美化…的环境; pine:n.松木;松树;vi.难过,悲伤 ferns:n.蕨类;[植]蕨类植物(fern的复数形式);
At the same time , there were small lizards , mammals , insects, and there were also carnivorous and herbivorous reptiles -- all competing for the same resources . 同时,还有小型蜥蜴, 哺乳动物,昆虫, 而且还有食肉和食草 的爬虫类动物—— 都在为相同的资源而竞争。
At the same time:同时;另一方面;与此同时; lizards:n.[动]蜥蜴,蜥蜴爬虫类动物;(lizard的复数) mammals:n.哺乳动物;(mammal的复数) carnivorous:adj.食肉的;肉食性的; herbivorous:adj.[动]食草的; reptiles:n.爬行动物(reptile的复数);[脊椎]爬行类;爬虫类; competing:adj.相互冲突的;相互矛盾的;v.竞争;对抗;参加比赛;(compete的现在分词) resources:n.[计][环境]资源; v.向…提供资金(resource的第三人称单数);
Critical to this story is that oxygen levels have been estimated to have been as low as 15 percent, compared to today's 21 percent. 这个故事还有重要的一点, 就是当时的大气层中 的氧气含量只有 15%, 现在则是 21%。
Critical:adj.鉴定的;[核]临界的;批评的,爱挑剔的;危险的;决定性的;评论的; estimated:adj.估计的;预计的;估算的; compared:adj.比较的,对照的; v.相比; (compare的过去式和过去分词)
So it would have been crucial for dinosaurs to be able to breathe in this low-oxygen environment, not only to survive but to thrive and to diversify . 所以对恐龙来说, 在这种低氧环境中呼吸 是至关重要的, 不仅仅为了生存, 还要能繁衍和多样化。
crucial:adj.重要的;决定性的;定局的;决断的; thrive:v.繁荣;茁壮成长;蓬勃发展;兴旺发达; diversify:vt.使多样化,使变化;增加产品种类以扩大;
So, how do we know what dinosaur lungs were even like, since all that remains of a dinosaur generally is its fossilized skeleton ? 那我们是如何知道 恐龙的肺长什么样子呢？ 它们遗留下来的只有化石骨架了。
generally:adv.通常;普遍地,一般地; fossilized:adj.石化的;僵化的;老化的;v.石化(fossilize的过去式和过去分词); skeleton:n.骨架,骨骼;纲要;骨瘦如柴的人;adj.骨骼的;骨瘦如柴的;概略的;
The method that we use is called " extant phylogenetic bracketing ." 我们采用的方法 是“现存系统发育分组”。
extant:adj.现存的;显著的; phylogenetic:adj.[生物]系统发生的;动植物种类史的; bracketing:n.托架;括弧;夹叉射击;
This is a fancy way of saying that we study the anatomy -- specifically in this case, the lungs and skeleton -- of the living descendants of dinosaurs on the evolutionary tree. 这只是一个专业名词, 意思是我们研究的生物结构—— 在这个例子中,尤其是肺和骨架—— 来自于恐龙在进化树中现存的后裔。
fancy:n.幻想; adj.想象的; v.想象; specifically:adv.特别地;明确地; descendants:n.后裔;后代;子孙;派生物;(descendant的复数)
So we would look at the anatomy of birds, who are the direct descendants of dinosaurs, and we'd look at the anatomy of crocodilians , who are their closest living relatives , 于是我们会研究鸟类的生物结构, 也就是恐龙的直接后代, 我们还会研究鳄鱼, 它们是恐龙最近的亲戚,
crocodilians:adj.鳄鱼的;鳄鱼一样的;伪善的;n.鳄目动物; relatives:n.亲戚;亲属;同类事物;(relative的复数)
and then we would look at the anatomy of lizards and turtles , who we can think of like their cousins. 还有蜥蜴和龟类, 它们也算是恐龙的表兄弟。
turtles:n.海龟;龟;陆龟;水龟;鳖;(turtle的复数)
And then we apply these anatomical data to the fossil record, and then we can use that to reconstruct the lungs of dinosaurs. 然后我们把这些生物结构数据 应用到化石记录中, 这样我们就可以重建恐龙的肺结构。
apply:v.申请;涂,敷;应用;适用;请求; anatomical:adj.解剖的;解剖学的;结构上的; reconstruct:vt.重建;改造;修复;重现;
And in this specific instance , the skeleton of dinosaurs most closely resembles that of modern birds. 在这个例子中, 恐龙的骨架和鸟类最相似。
instance:n.实例;情况;建议;v.举...为例; resembles:v.看起来像:显得像:像(resemble的第三人称单数)
So, because dinosaurs were competing with early mammals during this time period, it's important to understand the basic blueprint of the mammalian lung. 因为在远古时代 恐龙曾和哺乳动物竞争, 那么了解哺乳动物 的肺结构就尤为重要。
blueprint:vt.计划;制成蓝图;n.蓝图,设计图;计划; mammalian:adj.哺乳类动物的;n.哺乳类;
Also, to reintroduce you to lungs in general , we will use my dog Mila of Troy, the face that launched a thousand treats , as our model. 为了让你们重新熟悉肺结构, 我就用我的狗狗米拉—— 它可爱到可以骗取无数零食—— 来做模型。
reintroduce:vt.再引入;再提出;再介绍; in general:总之,通常;一般而言; launched:v.发射;发起;开展;开始;(launch的过去式和过去分词) treats:v.以…态度对待; n.乐事;
(Laughter) （笑声）
This story takes place inside of a chest cavity . 我们先来看看胸腔结构。
cavity:n.腔;洞,凹处;
So I want you to visualize the ribcage of a dog. 我想让你们先想象一下 一只狗的肋骨。
visualize:vt.形象,形象化;想像,设想;vi.显现; ribcage:n.胸腔;胸廓;
Think about how the spinal vertebral column is completely horizontal to the ground. 设想脊椎和脊柱 是和地面平行的。
spinal:adj.脊髓的;脊柱的;针的;脊骨的;尖刺的;n.脊椎麻醉; vertebral:adj.脊椎的;椎骨的;由椎骨组成的;有脊椎的; column:n.栏目,纵队; horizontal:n.水平线;水平面;横线;水平位置;adj.水平的;与地面平行的;横的;
This is how the spinal vertebral column is going to be in all of the animals that we'll be talking about, whether they walked on two legs or four legs. 我们接下来要讲的 所有动物的脊椎脊柱 和这个是一样的, 无论是两条腿走路的 还是四条腿。
Now I want you to climb inside of the imaginary ribcage and look up. 想象我们在胸腔内部, 然后朝上看。
imaginary:adj.虚构的,假想的;想像的;虚数的;
This is our thoracic ceiling. 那是我们的胸椎顶部。
thoracic:adj.[解剖]胸的;[解剖]胸廓的;
This is where the top surface of the lungs comes into direct contact with the ribs and vertebrae . 在这里我们的肺的最上部 会和肋骨,脊椎 有直接接触。
contact:n.接触,联系;v.使接触,联系; ribs:n.[解剖]肋骨;排骨(rib的复数); vertebrae:n.[解剖]椎骨;脊椎;
This interface is where our story takes place. 这个界面就是我们要讨论的地方。
interface:n.接口;人机界面;连接电路;v.连接;
Now I want you to visualize the lungs of a dog. 现在你们可以想象一只狗的肺。
On the outside, it's like a giant inflatable bag where all parts of the bag expand during inhalation and contract during exhalation . 在外面看似一个巨大的充气袋子, 吸气时会膨胀, 呼气时会收缩。
giant:n.巨人;伟人;巨兽;adj.巨大的;特大的 inflatable:adj.膨胀的,可充气的;得意的; expand:v.扩张;使膨胀;详述;发展;张开,展开; inhalation:n.吸入;吸入药剂; contract:v.收缩;感染;订约;n.合同;婚约; exhalation:n.蒸发,呼气;散发物;
Inside of the bag, there's a series of branching tubes, and these tubes are called the bronchial tree. 在袋子里面有一系列的分支气管, 这些气管叫做支气管树。
series:n.系列,连续;[电]串联;级数;丛书; bronchial:adj.支气管的;
These tubes deliver the inhaled oxygen to, ultimately , the alveolus . 这些气管把吸入的氧气运送到肺泡。
inhaled:v.吸入;吸气;(inhale的过去分词和过去式) ultimately:adv.最终;最后;归根结底;终究; alveolus:n.肺泡;小窝;
They cross over a thin membrane into the bloodstream by diffusion . 氧气再穿过一层薄膜 扩散进入血流。
membrane:n.膜;薄膜;羊皮纸; bloodstream:n.[生理]血流,血液的流动; diffusion:n.扩散,传播;[光]漫射;
Now, this part is critical. 这一步很关键。
The entire mammalian lung is mobile . 哺乳类动物的整个肺是可移动的。
mobile:n.手机;汽车;移动电话;adj.活跃的;可动的;
That means it's moving during the entire respiratory process , so that thin membrane, the blood-gas barrier , cannot be too thin or it will break. 这意味着在整个呼吸过程中 它都在移动, 所以那层血气屏障 如果太薄的话容易破损。
respiratory:adj.呼吸的; process:v.处理;加工;列队行进;n.过程,进行;方法,adj.经过特殊加工(或处理)的; barrier:n.屏障;障碍;障碍物;关口;v.用栅围住;
Now, remember the blood-gas barrier, because we will be returning to this. 我们等会儿还要回到那层薄膜。
So, you're still with me? 你们还跟得上吗？
Because we're going to start birds and it gets crazy, so hold on to your butts . 我们现在开始要讲鸟类了, 准备好。
hold on to:坚持;紧握;克制; butts:n.短硬黄麻根纤维; v.踩熄或捻熄香烟等;
(Laughter) （笑声）
The bird is completely different from the mammal. 鸟类和哺乳类动物完全不一样。
And we are going to be using birds as our model to reconstruct the lungs of dinosaurs. 我们要用鸟类作为模型来 重造恐龙的肺。
So in the bird, air passes through the lung, but the lung does not expand or contract. 在鸟类中, 空气通过肺, 但是肺部并不会膨胀或收缩,
The lung is immobilized , it has the texture of a dense sponge and it's inflexible and locked into place on the top and sides by the ribcage and on the bottom by a horizontal membrane. 它们的肺是无法移动的, 质地和一块厚海绵一样, 在肋骨的顶部和侧面都有连接, 还有底部水平的薄膜, 导致肺无法移动。
immobilized:v.使不动;使不能正常运作;(immobilize的过去分词和过去式) texture:n.质地;纹理;结构;本质,实质; dense:adj.稠密的;浓厚的;愚钝的; sponge:v.抹掉;用海绵擦拭;讨得;n.海绵;海绵状物; inflexible:adj.顽固的;不可弯曲的;不屈挠的;不能转变的;
It is then unidirectionally ventilated by a series of flexible, bag-like structures that branch off of the bronchial tree, beyond the lung itself, and these are called air sacs . 有一系列灵活的袋状结构 为它们的肺提供单向通风, 这些结构从支气管树延伸 到肺部的外面, 它们叫做气囊。
ventilated:adj.通风的;v.发表;使…通风(ventilate的过去分词); structures:n.结构; v.建造(structure的第三人称单数形式); sacs:n.[生物]囊,液囊;糖精(sac的复数);
Now, this entire extremely delicate setup is locked into place by a series of forked ribs all along the thoracic ceiling. 这个错综复杂的结构沿胸腔顶部 被一系列 分叉的肋骨锁定到位。
delicate:adj.精致的,微妙的,脆弱的,熟练的,柔和的;
Also, in many species of birds, extensions arise from the lung and the air sacs, they invade the skeletal tissues -- usually the vertebrae, sometimes the ribs -- and they lock the respiratory system into place. 而且,在许多鸟类体内, 肺部上方以及气囊包含 的延伸的结构 会扩张到骨骼组织中—— 通常是椎骨,有时是肋骨—— 它们让整个呼吸系统得到固定。
species:n.[生物]物种;种类; extensions:n.扩大;延伸;扩建部分;增建部分;(extension的复数) arise:v.出现;发生;产生;起身; invade:v.侵犯;侵略;侵袭;干扰; skeletal:adj.骨骼的,像骨骼的;骸骨的;骨瘦如柴的; tissues:n.纸巾,手巾纸;(人、动植物细胞的)组织;(tissue的复数)
And this is called "vertebral pneumaticity ." 这个结构叫做“椎体气动性”。
pneumaticity:n.有气腔;
The forked ribs and the vertebral pneumaticity are two clues that we can hunt for in the fossil record, because these two skeletal traits would indicate that regions of the respiratory system of dinosaurs are immobilized. 这些分叉的肋骨和椎体气动性 是两个在化石中有迹可循的线索, 因为这两个骨骼特征 表明恐龙的呼吸系统 也是不可移动的。
clues:n.(调查,研究等的)线索;迹象;(故事的)关键情节;(clue的复数) traits:n.特性,特质,性格(trait的复数); indicate:v.表明;显示;象征;暗示; regions:n.地区;地域;行政区;左近;(region的复数)
This anchoring of the respiratory system facilitated the evolution of the thinning of the blood-gas barrier, that thin membrane over which oxygen was diffusing into the bloodstream. 呼吸系统的不可移动性 推动了血气屏障—— 也就是那层协助氧气 扩散到血液中的薄膜—— 朝着变薄的方向进化。
facilitated:v.促进;促使;使便利;(facilitate的过去分词和过去式) diffusing:v.散布,传播;漫射(diffuse的现在分词形式);
The immobility permits this because a thin barrier is a weak barrier, and the weak barrier would rupture if it was actively being ventilated like a mammalian lung. 肺的不可移动性可以使 那层薄膜变得脆弱, 那层薄膜在十分通风的情况下 很容易破裂, 就像哺乳类动物的肺 所处的环境一样。
immobility:n.不动,固定; rupture:n.破裂;决裂;疝气;vi.破裂;发疝气;vt.使破裂;断绝;发生疝;
So why do we care about this? 我们为什么要关心这个呢？
Why does this even matter? 有什么意义吗？
Oxygen more easily diffuses across a thin membrane, and a thin membrane is one way of enhancing respiration under low-oxygen conditions -- low-oxygen conditions like that of the Triassic period. 氧气更容易通过薄膜扩散, 薄膜是在低氧环境下 提高呼吸率的一种办法—— 比如三叠纪的低氧环境中。
diffuses:adj.弥漫的;散开的;vt.扩散;传播;漫射;vi.传播;四散; enhancing:n.优化,增强;暖色加重效果;v.增强(enhance的现在分词); respiration:n.呼吸;呼吸作用;
So, if dinosaurs did indeed have this type of lung, they'd be better equipped to breathe than all other animals, including mammals. 如果恐龙的确有这种肺结构, 它们就比别的动物 具备更好的呼吸系统, 包括哺乳动物。
So do you remember the extant phylogenetic bracket method where we take the anatomy of modern animals, and we apply that to the fossil record? 你们还记得现存系统发育分组法吗？ 也就是我们用现代动物的构造 来应用到化石记录中。
So, clue number one was the forked ribs of modern birds. 线索一就是现代鸟类的分叉的肋骨。
Well, we find that in pretty much the majority of dinosaurs. 这一点在几乎所有恐龙中都可以找到。
majority:n.大部分:大多数:多数票:成年人:
So that means that the top surface of the lungs of dinosaurs would be locked into place, just like modern birds. 这意味着恐龙的肺的顶部 是锁定到位的, 就像现存的鸟类一样。
Clue number two is vertebral pneumaticity. 线索二是椎体气动性。
We find this in sauropod dinosaurs and theropod dinosaurs, which is the group that contains predatory dinosaurs and gave rise to modern birds. 我们在蜥脚类恐龙和兽脚类恐龙, 也就是掠食性恐龙中, 都可以找到, 它们也就是现代鸟类的祖先。
sauropod:n.蜥脚类动物;adj.蜥脚类动物的; theropod:n.兽脚类的肉食恐龙;adj.兽脚亚目的; predatory:adj.掠夺的,掠夺成性的;食肉的;捕食生物的;
And while we don't find evidence of fossilized lung tissue in dinosaurs, vertebral pneumaticity gives us evidence of what the lung was doing during the life of these animals. 虽然我们没有恐龙的肺化石, 但椎体气动性可以告诉我们 恐龙存活时 肺的大致功能。
evidence:n.证据,证明;迹象;明显;v.证明;
Lung tissue or air sac tissue was invading the vertebrae, hollowing them out just like a modern bird, and locking regions of the respiratory system into place, immobilizing them. 肺组织和气囊组织侵入椎骨中, 使其变成空心,就如现代鸟类一样, 使部分呼吸系统锁定在位, 让肺无法移动。
invading:v.武装入侵;侵略;侵犯;涌入;干扰(invade的现在分词) hollowing:n.打凹成形(雕塑技法);v.挖空,弄凹(hollow的ing形式); immobilizing:v.使不动(immobilize的ing形式);
The forked ribs and the vertebral pneumaticity together were creating an immobilized, rigid framework that locked the respiratory system into place that permitted the evolution of that superthin, superdelicate blood-gas barrier that we see today in modern birds. 分叉的肋骨 和椎体气动性一起 创造了一个无法移动的, 坚硬的构架, 把整个呼吸系统锁定到位, 使得我们今天在现代鸟类身上 看到的超薄、超脆弱 的血气屏障得以进化。
rigid:adj.严格的;僵硬的,死板的;坚硬的;精确的;
Evidence of this straightjacketed lung in dinosaurs means that they had the capability to evolve a lung that would have been able to breathe under the hypoxic , or low-oxygen, atmosphere of the Triassic period. 恐龙有不可移动肺的证据 意味着它们可以演化出一个 能在低氧环境中呼吸的肺, 让它们在三叠纪大气层中得以存活。
capability:n.才能,能力;性能,容量; evolve:v.(使)逐渐形成;进化;进化形成; hypoxic:含氧量低的; atmosphere:n.大气;气氛;气压;风格;
This rigid skeletal setup in dinosaurs would have given them a significant adaptive advantage over other animals, particularly mammals, whose flexible lung couldn't have adapted to the hypoxic, or low-oxygen, atmosphere of the Triassic. 这样的肺结构使它们 与其他动物,尤其是哺乳类动物相比, 有巨大的适应性优势, 因为其他动物可移动的肺 无法适应三叠纪的低氧环境。
significant:adj.重大的;有效的;有意义的;值得注意的;意味深长的;n.象征;有意义的事物; adaptive:adj.适应的,适合的; advantage:n.有利条件:优势:优点: particularly:adv.特别地,独特地;详细地,具体地;明确地,细致地; adapted:adj.适于…的; v.使适应,使适合; (adapt的过去分词和过去式)
This anatomy may have been the secret weapon of dinosaurs that gave them that advantage over other animals. 这样的生物结构也许 就是恐龙的秘密武器, 可以带给它们巨大的生存优势。
And this gives us an excellent launchpad to start testing the hypotheses of dinosaurian diversification . 这也为我们去测试恐龙多样化 的假设提供了良好的基石。
launchpad:n.发射坪;发射台; hypotheses:n.假定;臆测(hypothesis的复数); dinosaurian:adj.恐龙的;n.恐龙; diversification:n.多样化;变化;
This is the story of the dinosaurs' beginning, and it's just the beginning of the story of our research into this subject. 这就是恐龙生存繁衍的故事, 也只是我们在这一领域研究的开端。
Thank you. 谢谢。
(Applause) （掌声）