经济学人136:进化和表皮色彩

 　　Science and technology

　　科学与技术

　　Evolution and coat colour

　　进化和表皮色彩

　　Well spotted¹

　　美丽涂鸦

　　The reason why some cats are plain and others are patterned

　　为何有些猫科动物全无斑纹，而其他的则斑斑点点？

　　How the leopard² got his spots is, famously, the subject of one of Rudyard Kipling's “Just So Stories”.

　　美洲豹为何满身斑点？这是吉卜林大作《原来如此》中的一个著名问题。

　　Kipling suggested they were handprints made by the leopard's human friend. More plausibly³, he had an explanation for what the spots are for: to break up the animal's shape when it is hiding in the dappled light of the forest.

　　吉卜林认为，那是美洲豹的人类朋友们留下的手印。他更靠谱的解释是，当美洲豹藏身在树丛的斑驳光影之中，斑点有助于让它们“隐去”形迹。

　　These days, the human-handprint theory of the leopard's spots has fallen out of favour.

　　最近，美洲豹斑点的手印理论已不合口味。

　　Instead, a more prosaic⁴ idea has gained ground, based on what is known as reaction-diffusion pattern formation, in which chemicals that trigger the differentiation⁵ of cells in an embryo⁶ interact with one another to produce patterns that are then reflected in the fates of nearby cells.

　　取而代之并渐为人知的是一种更乏味的观点：斑点产生于“反应－扩散”的图案形成过程，其中，胚胎细胞分化由化学反应引发，各类化学反应之间又发生作用，其作用模式最后在表皮细胞的发育中表现出来。

　　But that, too, has its difficulties. Just how much a process like this can be shaped by natural selection is unclear.

　　但这一说也有其困难，它在多大程度上收到自然选择的影响，目前尚不清楚。

　　Reaction-diffusion patterns which can be created in a laboratory using standard reagents are simple and deterministic.

　　反应－扩散模式可在实验室用标准试剂产生简洁而又有说服力。

　　That simple reactions of this sort sometimes result in cryptic⁷ patterns could be a coincidence.

　　这类偶尔引发神奇图案的简单反应纯粹是巧合。

　　Nevertheless, the details of the patterns produced vary, according to things like how rapidly the chemicals diffuse⁸.

　　不过，图案产生的细节各各不同，依据诸如扩散速度等情形而有差别。

　　That could be selected. Different cats do, indeed, have different patterns.

　　这就可加以选择。确实，不同的猫科动物有不同图案。

　　So researchers at the University of Bristol, led by William Allen, have been deconstructing these patterns, trying to match the elements to cats' habits and habitats, and thus show whether the patterns are evolving.

　　因此，在威廉姆﹒艾伦的带领下，布里斯托大学的研究者正在分解这些图案，并尝试把图案要素同猫科动物的习性与栖息地匹配起来，以发现图案是否会发生进化。

　　They published their results this week in the Proceedings⁹ of the Royal Society.

　　本周他们在《皇家学会学报》上发表了研究结果。

　　The reaction-diffusion process can be mimicked¹⁰ by a computer, and the program's parameters¹¹ manipulated to produce patterns matching those of cat coats.

　　反应－扩散过程可以用计算机加以模拟，对程序参数也可加控制，以产生同猫科动物外表匹配的图案。

　　That, the researchers hoped, might help illuminate¹² what is going on.

　　研究者希望借此搞清楚到底发生了什么。

　　They trawled the world wide web for pictures of wild cats, found the best six for each of 37 species, and roped in a group of human volunteers to choose which of the program's outputs were most similar to real coats.

　　他们在互联网上搜罗野生猫科动物的图片，为37个猫科物种的每一种都准备了最佳的6张照片，并说服一批人类志愿者来判定：哪个程序的输出结果和真实的外表最为相似。

　　The patterns produced had five parameters: how plain they were, how irregular, how complex, how big the spots were and whether the pattern had a perceptible direction to it.

　　为产生图案设置了5个参数：斑点的有无程度、规则程度、复杂程度、大小程度、是否有明显的生长位置。

　　The volunteers' judgments¹³ about which artificial patterns best matched which natural ones were almost perfectly¹⁴ consistent.

　　志愿者关于人工图案与自然图案匹配程度的判断几乎完美的一致。

　　That allowed Mr Allen to assess which parameters contribute to each species's pattern, and thus which are correlated with behaviour.

　　这使艾伦先生可以推断哪个参数对物种的图案起了影响，从而进一步同物种行为联系起来。

　　The biggest distinction—no surprise, but nice to confirm—is that spotted cats are forest cats and plain ones prefer open countryside.

　　最大的区别发现本身并不出人意料，但推理非常严密是：有斑点的猫科动物生活在丛林中，没有斑点的更偏好生活在开阔的平原地带。

　　In that, Kipling was right.

　　在这点上，吉卜林是对的。

　　An analysis based on the relationship between the species, though, shows that evolutionary¹⁵ lines can swap¹⁶ from spots to no spots, and vice¹⁷ versa, as the habitat dictates¹⁸.

　　基于物种关系的一个分析表明，进化路线有时是从有斑点到无斑点，有时又反过来，这取决于栖息地在哪里。

　　Moreover, the more a species prefers the forest, the more irregular the pattern it sports, and the more complex.

　　并且，如果一个物种越是喜欢丛林生活，图案就越是不规则，越加复杂对大小和图案生长位置没有影响。

　　Size and direction have no effect.Even among forest-dwellers there are differences.

　　即使丛林物种之间也不一样。

　　Those that tend to spend their time actually in trees, as opposed to wandering around on the ground between them, have more irregular and complex patterns.

　　与那些喜欢呆在地上的相比，更多时间呆在树上的种群，其图案就更不规则，更加复杂。

　　And, crucially, there is no relationship between a cat's pattern and how sociable¹⁹ it is.

　　并且，重要的是在猫科动物的图案和社群习性之间没有关联。

　　That knocks on the head an alternative explanation for coat patterns, namely that spots are some form of signal between animals of the same species.

　　这对关于表皮图案的另一理论解释是当头一击，此种解释认为斑点是同一动物种群的共有标记形式。

　　Mr Allen and his colleagues made one other observation. Some species of cat regularly produce melanic forms—the so-called black panther actually a melanic jaguar²⁰ being the most familiar.

　　艾伦先生及其同事还作了其他的观察。某些猫科动物会周期性变成黑色——例如大家熟悉的黑豹实际上是黑色的美洲虎。

　　The data seem to rule out one obvious explanation for melanism: the idea that black cats, with their unusual appearance, have more success hunting because their prey²¹ are not keeping an eye out for predators²² that look like them.

　　这一观察似乎也排除了“黑变论”的解释。这种说法是，黑色猫科动物因其不同寻常的外表，而在捕猎方面非常成功，因为它们无须留神被猎物看见。

　　Melanic forms, though, are particularly prevalent in species with complicated lives—those that inhabit a range of habitats, are active both day and night, and move between the ground and the trees.

　　可是，黑色外表为各种复杂形式的物种所有，它们栖息在不同地带、有白天活动的也有黑夜活动的、有在地面生存的也有在树上生存的。

　　What advantage melanism brings in these circumstances is obscure.

　　在这些环境中表皮黑化到底有什么优势似乎模糊不清。

　　One for Kipling, perhaps. “How the jaguar got his melanocytes.”

　　这问题可能要交给吉卜林了：“美洲虎为何是黑色？”

　　1.evolution n.进化；发展

　　Charles Darwin and Alfred Russell Wallace discovered evolution independently.

　　查尔斯·达尔文和阿尔弗雷德· 罗素·华莱士各自独立地发现了进化论。

　　Within 30 years,humans could be debating whether to take charge of their own evolution.

　　不出30年，人类将讨论是否要掌控自身的进化。

　　Our watchword is: ‘Evolution, not revolution’.

　　我们的口号是: ‘要循序渐进,不要剧烈变革’。

　　Our political institutions are in continuous evolution.

　　我们的政治制度正在不断发展中。

　　In politics Britain has preferred evolution to revolution.

　　在政治上，英国喜欢渐进而不喜欢革命。

　　2.dapple n.斑纹；斑点

　　The sun shinning through the leaves dappled the ground.

　　阳光穿过树叶照在地上，现出一块块亮斑。

　　The dapple of the deer is yellow.

　　鹿的斑点是黄色的。

　　3.trigger v.使发生；触发

　　Price increases will trigger off demands for wage increases.

　　价格上涨会激发人们增长工资的要求。

　　The odour of food may trigger people's appetite.

　　食物的香味能引起人的食欲。

　　A detonator is used to trigger an explosive device.

　　雷管用来引爆爆炸装置。

　　4.cryptic a.隐秘的；秘密的

　　A cryptic message said France needs to pull troops out of Afghanistan.

　　一个神秘消息要求法国需要从阿富汗撤军。

　　I don't know what this cryptic remark is intended to convey.

　　我不知道这句暗藏玄机的评语是要表示什么。

1 spotted   

adj.有斑点的，斑纹的，弄污了的

参考例句：

• The milkman selected the spotted cows,from among a herd of two hundred.牛奶商从一群200头牛中选出有斑点的牛。
• Sam's shop stocks short spotted socks.山姆的商店屯积了有斑点的短袜。

2 leopard   

n.豹

参考例句：

• I saw a man in a leopard skin yesterday.我昨天看见一个穿着豹皮的男人。
• The leopard's skin is marked with black spots.豹皮上有黑色斑点。

3 plausibly   

似真地

参考例句：

• The case was presented very plausibly. 案情的申述似很可信。
• He argued very plausibly for its acceptance. 他为使之认可辩解得头头是道。

4 prosaic   

adj.单调的，无趣的

参考例句：

• The truth is more prosaic.真相更加乏味。
• It was a prosaic description of the scene.这是对场景没有想象力的一个描述。

5 differentiation   

n.区别，区分

参考例句：

• There can be no differentiation without contrast. 有比较才有差别。
• The operation that is the inverse of differentiation is called integration. 与微分相反的运算叫做积分。

6 embryo   

n.胚胎，萌芽的事物

参考例句：

• They are engaging in an embryo research.他们正在进行一项胚胎研究。
• The project was barely in embryo.该计划只是个雏形。

7 cryptic   

adj.秘密的，神秘的，含义模糊的

参考例句：

• She made a cryptic comment about how the film mirrored her life.她隐晦地表示说这部电影是她人生的写照。
• The new insurance policy is written without cryptic or mysterious terms.新的保险单在编写时没有隐秘条款或秘密条款。

8 diffuse   

v.扩散；传播；adj.冗长的；四散的，弥漫的

参考例句：

• Direct light is better for reading than diffuse light.直射光比漫射光更有利于阅读。
• His talk was so diffuse that I missed his point.他的谈话漫无边际，我抓不住他的要点。

9 proceedings   

n.进程，过程，议程；诉讼(程序)；公报

参考例句：

• He was released on bail pending committal proceedings. 他交保获释正在候审。
• to initiate legal proceedings against sb 对某人提起诉讼

10 mimicked   

v.（尤指为了逗乐而）模仿( mimic的过去式和过去分词 )；酷似

参考例句：

• He mimicked her upper-class accent. 他模仿她那上流社会的腔调。 来自辞典例句
• The boy mimicked his father's voice and set everyone off laughing. 男孩模仿他父亲的嗓音，使大家都大笑起来。 来自辞典例句

11 parameters   

因素，特征； 界限； （限定性的）因素( parameter的名词复数 )； 参量； 参项； 决定因素

参考例句：

• We have to work within the parameters of time. 我们的工作受时间所限。
• See parameters.cpp for a compilable example. This is part of the Spirit distribution. 可编译例子见parameters.cpp.这是Spirit分发包的组成部分。

12 illuminate   

vt.照亮，照明；用灯光装饰；说明，阐释

参考例句：

• Dreams kindle a flame to illuminate our dark roads.梦想点燃火炬照亮我们黑暗的道路。
• They use games and drawings to illuminate their subject.他们用游戏和图画来阐明他们的主题。

13 judgments   

判断( judgment的名词复数 )； 鉴定； 评价； 审判

参考例句：

• A peculiar austerity marked his judgments of modern life. 他对现代生活的批评带着一种特殊的苛刻。
• He is swift with his judgments. 他判断迅速。

14 perfectly   

adv.完美地，无可非议地，彻底地

参考例句：

• The witnesses were each perfectly certain of what they said.证人们个个对自己所说的话十分肯定。
• Everything that we're doing is all perfectly above board.我们做的每件事情都是光明正大的。

15 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• 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。

16 swap   

n.交换；vt.交换，用...作交易

参考例句：

• I will swap you my bicycle for your radio.我想拿我的自行车换你的收音机。
• This comic was a swap that I got from Nick.这本漫画书是我从尼克那里换来的。

17 vice   

n.坏事；恶习；[pl.]台钳，老虎钳；adj.副的

参考例句：

• He guarded himself against vice.他避免染上坏习惯。
• They are sunk in the depth of vice.他们堕入了罪恶的深渊。

18 dictates   

n.命令，规定，要求( dictate的名词复数 )v.大声讲或读( dictate的第三人称单数 )；口授；支配；摆布

参考例句：

• Convention dictates that a minister should resign in such a situation. 依照常规部长在这种情况下应该辞职。 来自《简明英汉词典》
• He always follows the dictates of common sense. 他总是按常识行事。 来自《简明英汉词典》

19 sociable   

adj.好交际的，友好的，合群的

参考例句：

• Roger is a very sociable person.罗杰是个非常好交际的人。
• Some children have more sociable personalities than others.有些孩子比其他孩子更善于交际。

20 jaguar   

n.美洲虎

参考例句：

• He was green with envy when he saw my new Jaguar car.看见我那辆美洲虎牌新车，他非常妒忌。
• Should you meet a jaguar in the jungle,just turn slowly,walk away.But slowly,never look back.你在丛林中若碰上美洲虎，就慢慢转身走开，可一定要慢，切莫回头看。

21 prey   

n.被掠食者，牺牲者，掠食；v.捕食，掠夺，折磨

参考例句：

• Stronger animals prey on weaker ones.弱肉强食。
• The lion was hunting for its prey.狮子在寻找猎物。

22 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》