双语有声阅读：进化与轮子
时间：2019-02-17 作者：英语课 分类：双语有声阅读
英语课
进化与轮子
从前，研究自然界没有轮子的进化论生物学家都同意不能用无此需要来解释这种现象：轮子对于动物会像对于我们人类一样有好处。 生物学家们推论，动物没有进化出轮子是由下述困难所致：动物身上的活细胞通过血管与心脏相连，通过神经与大脑相连。 因为一个旋转的接头对轮子来说是至关重要的，由活的细胞构成的轮子在第一次转动时便会扭伤其上的动脉和神经的连结，因而不现实。
不过，动物未能进化出轮子是受阻于无法解决接头问题的说法有一个缺陷。 这种理论无法解释为何动物没有进化出由死组织构成的而无需动脉和神经的轮子。 包括人在内的无数动物都有一些没有血液供应和神经的体外构造，例如，我们的头发和指甲，或者鳞片、爪子和其它一些动物的角。为什么老鼠没有进化出类似于滑轮溜冰鞋的骨质的轮子呢?在某些情况下，爪子可能比轮子更有用，但猫的爪子是可以伸缩的： 为什么不能有可以伸缩的轮子呢?这样，我们便得出了一个被戏称为RRR 的严肃的生物学悖论：大自然未能产生出有可伸缩的滑轮溜冰鞋的老鼠。
Evolution and Wheels
In the past, evolutionary 1 biologists contemplating 2 the absence of wheels in nature agreed that the explanation was not undesirability 3: wheels would be good for animals, just as they are for us. Animals were prevented from evolving wheels, the biologists reasoned, by the following dilemma 4: living cells in an animal's body are connected to the heart by blood vessels 5, and to the brain by nerves. Because a rotating joint 6 is essential to a wheel, a wheel made of living cells would twist its artery 7 vein 8 and nerve connections at the first revolution, making living impracticable.
However, there is a flaw in the argument that the evolution of wheeled animals was thwarted 9 by the insoluble joint problem. The theory fails to explain why animals have not evolved wheels of dead tissue with no need for arteries 10 and nerves. Countless 11 animals, including us, bear external structures without blood supply or nerves - for example, our hair and fingernails, or the scales, claws, and ho rns of other animals. Why have rats not evolved bony wheels, similar to roller skates?Paws might be more useful than wheels in some situations, but cats' claws are retractable 12: why not retractable wheels?We thus arrive at the serious biological paradox 13 flippantly termed the RRR dilemma: nature's failure to produce rats with retractable roller skates.
从前，研究自然界没有轮子的进化论生物学家都同意不能用无此需要来解释这种现象：轮子对于动物会像对于我们人类一样有好处。 生物学家们推论，动物没有进化出轮子是由下述困难所致：动物身上的活细胞通过血管与心脏相连，通过神经与大脑相连。 因为一个旋转的接头对轮子来说是至关重要的，由活的细胞构成的轮子在第一次转动时便会扭伤其上的动脉和神经的连结，因而不现实。
不过，动物未能进化出轮子是受阻于无法解决接头问题的说法有一个缺陷。 这种理论无法解释为何动物没有进化出由死组织构成的而无需动脉和神经的轮子。 包括人在内的无数动物都有一些没有血液供应和神经的体外构造，例如，我们的头发和指甲，或者鳞片、爪子和其它一些动物的角。为什么老鼠没有进化出类似于滑轮溜冰鞋的骨质的轮子呢?在某些情况下，爪子可能比轮子更有用，但猫的爪子是可以伸缩的： 为什么不能有可以伸缩的轮子呢?这样，我们便得出了一个被戏称为RRR 的严肃的生物学悖论：大自然未能产生出有可伸缩的滑轮溜冰鞋的老鼠。
Evolution and Wheels
In the past, evolutionary 1 biologists contemplating 2 the absence of wheels in nature agreed that the explanation was not undesirability 3: wheels would be good for animals, just as they are for us. Animals were prevented from evolving wheels, the biologists reasoned, by the following dilemma 4: living cells in an animal's body are connected to the heart by blood vessels 5, and to the brain by nerves. Because a rotating joint 6 is essential to a wheel, a wheel made of living cells would twist its artery 7 vein 8 and nerve connections at the first revolution, making living impracticable.
However, there is a flaw in the argument that the evolution of wheeled animals was thwarted 9 by the insoluble joint problem. The theory fails to explain why animals have not evolved wheels of dead tissue with no need for arteries 10 and nerves. Countless 11 animals, including us, bear external structures without blood supply or nerves - for example, our hair and fingernails, or the scales, claws, and ho rns of other animals. Why have rats not evolved bony wheels, similar to roller skates?Paws might be more useful than wheels in some situations, but cats' claws are retractable 12: why not retractable wheels?We thus arrive at the serious biological paradox 13 flippantly termed the RRR dilemma: nature's failure to produce rats with retractable roller skates.
adj.进化的；演化的，演变的；[生]进化论的
- Life has its own evolutionary process.生命有其自身的进化过程。
- These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。
深思，细想，仔细考虑( contemplate的现在分词 )； 注视，凝视； 考虑接受（发生某事的可能性）； 深思熟虑，沉思，苦思冥想
- You're too young to be contemplating retirement. 你考虑退休还太年轻。
- She stood contemplating the painting. 她站在那儿凝视那幅图画。
n.不受欢迎
- Being dateless on New Year's Eve is proof positive of a person's social and sexual undesirability. 除夕时没有约会是社交上不受欢迎，而且缺乏性魅力的铁证。
n.困境，进退两难的局面
- I am on the horns of a dilemma about the matter.这件事使我进退两难。
- He was thrown into a dilemma.他陷入困境。
n.血管( vessel的名词复数 )；船；容器；（具有特殊品质或接受特殊品质的）人
- The river is navigable by vessels of up to 90 tons. 90 吨以下的船只可以从这条河通过。 来自《简明英汉词典》
- All modern vessels of any size are fitted with radar installations. 所有现代化船只都有雷达装置。 来自《现代汉英综合大词典》
adj.联合的，共同的；n.关节，接合处；v.连接，贴合
- I had a bad fall,which put my shoulder out of joint.我重重地摔了一跤，肩膀脫臼了。
- We wrote a letter in joint names.我们联名写了封信。
n.干线，要道；动脉
- We couldn't feel the changes in the blood pressure within the artery.我们无法感觉到动脉血管内血压的变化。
- The aorta is the largest artery in the body.主动脉是人体中的最大动脉。
n.血管，静脉；叶脉，纹理；情绪；vt.使成脉络
- The girl is not in the vein for singing today.那女孩今天没有心情唱歌。
- The doctor injects glucose into the patient's vein.医生把葡萄糖注射入病人的静脉。
阻挠( thwart的过去式和过去分词 )； 使受挫折； 挫败； 横过
- The guards thwarted his attempt to escape from prison. 警卫阻扰了他越狱的企图。
- Our plans for a picnic were thwarted by the rain. 我们的野餐计划因雨受挫。
n.动脉( artery的名词复数 )；干线，要道
- Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
- This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》
adj.无数的，多得不计其数的
- In the war countless innocent people lost their lives.在这场战争中无数无辜的人丧失了性命。
- I've told you countless times.我已经告诉你无数遍了。
adj.可收回的；可撤消的；可缩回的；可缩进的
- a knife with a retractable blade 弹簧刀
- So, any thoughts of what you want for the retractable bed kid? 那么想为那个睡折叠床的小子做什么？ 来自电影对白