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2017年12月18日 11:23:08来源:兰州晨报


  • Don:Hey, Yale. Would you rather be bitten by a saber-toothed tiger or a modern day tiger?唐:嘿,雅艾尔。你宁愿被剑齿虎咬还是被现代的老虎咬?Yael:Neither, of course. But if I have to pick, I supposed I choose the modern tiger. Since the saber-toothed tiger massive fangs.雅艾尔:都不愿意。如果一定要选的话,我情愿选现代的老虎。因为剑齿虎长有巨大的獠牙。Don:Well, you may be surprised to learn that paleontologists now think that despite their huge, fearsome looking canine teeth, the prehistoric American sabercat, Smilodon fatalis, had a bite force only about one-third as strong as modern big cats.唐:不过,古生物学家认为除了巨大的、长相可怕的犬齿之外,美国史前剑齿虎 Smilodon fatalis 的咬合力只有现代大猫的三分之一,知道这一点你可能会觉得很惊讶。Yael:How can they told that from fossilized bones?雅艾尔:他们是如何根据骨头化石得知咬合力的?Don:They used very fine CT scans of the skull, jaw and neck bones to create a highly detailed 3 D computer model. Then using careful analysis of the size and placement of muscle attachment points and mathematical modeling they were able to calculate the power of the jaw muscles and the bite force of the now extinct sabercats. This was the most detailed computer model ever created for a vertebrate.唐:他们用精密的CT扫描仪扫描头骨,颚和颈椎骨,用来建立一个高度精确的3D电脑模型。然后仔细分析肌肉附着点的尺寸和位置,利用这些数据进行数学建模,这样他们才能够计算出目前已经灭绝的剑齿虎的颚肌的力量和咬合力。这是人们迄今建立的最精确的脊椎动物电脑模型。Yael:Neat! So if they had such a wimpy bite, whats with the huge fangs?雅艾尔:做得好!那么如果它们的咬合力小,那么这些獠牙还有何用?Don:The function of the sabercats eight inch teeth is one of the longest running debates in paleontology. The results of this study support the hypothesis that the sabercats brought down and subdued large prey, like mammoths, with their strong forelimbs. Once the prey was safely restrained on the ground, sabercats used their large fangs to pierce through the thick hide on the neck of their quarry. In contrast, modern day big cats use their more powerful jaws to bite the neck of their prey for an extended period to subdue them by asphyxiation.唐:剑齿虎的门牙有八英尺长,至于它的作用至今仍是古生物学届最持久的争议话题之一。这项研究的结果持这种假说:剑齿虎使用强壮的前肢扑倒和制像猛犸象这样的大型猎物。一旦猎物被彻底制在地上,剑齿虎便用它那巨大的獠牙刺穿猎物脖子上的厚皮。相反,现代的大猫则利用更锋利的颚来长时间咬住猎物的脖子,直到它们窒息而亡。Yael:Yikes!I think Ill pass on being bitten by either a sabercat or a modern day tiger.雅艾尔:呀!我想在剑齿虎或者现代老虎咬我的时候,我就会不行了。Don:Wise choice.唐:明智的选择。原文译文属!201304/233270
  • Don: Time now for another episode of A Moment of Sciences ;Did You Know...; So, Yael, did you know that there have been about twenty-three mass extinctions since life began on earth?唐:现在进入科学时刻另一段情节:“你知道...”那么,雅艾尔,你知道吗,地球上自有生命以来发生过23起物种大灭绝事件?Yael: I know thereve been a few extinctions, Don, but not that many!雅艾尔:我知道几次物种大灭绝,但不知道次数如此多!Don: Yep. Many were of prehistoric bacteria and other single-celled microorganisms. But in the past 540 million years or so there have been about five mass extinctions, mainly of marine plants and animals but also of land organisms.唐:是啊。许多都是史前的细菌或其它单细胞微生物。但是在5.4亿年前已发生过5次大灭绝,主要包括海生植物和动物,当然也有陆生生物。Yael: Well, I know that the dinosaurs disappeared about 65 million years ago, possibly due to a large meteor that crashed into earth and blotted out the sun. But what caused all those other extinctions?雅艾尔:好吧,我知道恐龙大约在六千五百万年前消失,可能是由于一颗大流星撞击地球,遮住阳光引起的。但是什么导致其他物种灭绝的呢?Don: Thats been a mystery for a long time. But now some scientists think that most mass extinctions have been driven by the rise and fall of sea level. That may sound strange, but consider that millions of years ago a shallow sea covered the entire middle section of North America. That sea grew and shrank back several times. Each time it drained it caused entire species of sea plants and creatures to die off. The last time it drained was around 65 million years ago—when the dinosaurs disappeared.唐:长期以来那一直是个谜。但如今一些科学家们认为大多数的灭绝是由于海平面的上升和下降引起的。这也许听起来很奇怪,但考虑到百万年前有一片浅海覆盖在整个北美洲中部就不足为奇了。那片海历经几次扩张和消失,每一次干涸就会导致这个海洋的生物灭绝。最后一次干涸发生在6500万年前恐龙消失的时候。Yael: OK, I understand how a sea vanishing would kill off marine life. But did the seas disappearance also have something to do with the dinosaurs going extinct?雅艾尔:好吧,我明白了海洋的消失会引起海洋生物消失。但海洋的消失与恐龙的灭绝也有联系吗?Don: Maybe. When a sea disappears it has a big effect on climate. All that water provides heat and moisture. And when a sea drains, the climate becomes drier and colder. So the change in climate may have combined with the meteor impact to kill off the dinosaurs. 唐:也许。海洋消失会对气候产生深远的影响。海水能提供热量和湿度。当海水干枯时,气候就会变得更加干燥和寒冷。因此气候变化再加上流星撞击地球足以将恐龙推向毁灭。原文译文属!201305/240934
  • The two touch.交织在一起。It seems as if Pucks reassuring that all is OK.Samu suckles for the briefest moments.好像帕克在安慰它,没事的,没问题。莎木喝了几口奶。One small fish is not enough to keep the growing cafl going.小鱼还不能喂饱成长中的莎木。Despite of increasing independence, the bond between mother and son is extremely strong.尽管它越来越独立,但母子关系还是很牢靠。As the endlessly energetic Samu rushes off to play, closing one eye, Puck graps achance for a quick nap.莎木总是精力充沛的玩耍,帕克闭上眼睛,打了个盹。It is tiring to raise a youngster.照看孩子很累人。Lying still in the shallows, Puck sleeps with half of brain awake.帕克躺在浅水区,半睡半醒。She has to cautiously breathe or she has to drown.它必须这样呼吸空气,才不会被溺死。While his mother snoozes, Janet is watching Samu.海豚妈妈打盹的间隙,珍妮特正在照看莎木。She sees something she has never seen before.她看到了从未见过的一幕。Samu joints up with one of Pucks granddaughters.莎木和帕克的外孙女呆在一起。The young female appears to be given in fishing lessons.雌海豚教她如何。201406/308408
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