21 Summary

I have now completed a brief, and necessarily very imperfect, survey of the various ways in which the external form and colouring of animals is adapted to be useful to them, either by concealing² them from their enemies or from the creatures they prey³ upon. It has, I hope, been shown that the subject is one of much interest, both as regard a true comprehension of the place each animal fills in the economy of nature, and the means by which it is enabled to maintain that place; and also as teaching us how important a part is played by the minutest details in the structure of animals, and how complicated and delicate is the equilibrium⁴ of the organic world.

My exposition of the subject having been necessarily somewhat lengthy⁵ and full of details, it will be as well to recapitulate⁶ its main points.

There is a general harmony in nature between the colours of an animal and those of its habitation. Arctic animals are white, desert animals are sand-coloured; dwellers⁷ among leaves and grass are green; nocturnal animals are dusky. These colours are not universal, but are very general, and are seldom reversed. Going on a little further, we find birds, reptiles⁸, and insects, so tinted⁹ and mottled as exactly to match the rock, or bark, or leaf, or flower, they are accustomed to rest upon — and thereby¹⁰ effectually concealed¹¹. Another step in advance, and we have insects which are formed as well as coloured so as exactly to resemble particular leaves, or sticks, or mossy twigs¹², or flowers; and in these cases very peculiar¹³ habits and instincts come into play to aid in the deception¹⁴ and render the concealment¹⁵ more complete. We now enter upon a new phase of the phenomena¹⁶, and come to creatures whose colours neither conceal¹ them nor make them like vegetable or mineral substances; on the contrary, they are conspicuous¹⁷ enough, but they completely resemble some other creature of a quite different group, while they differ much in outward appearance from those with which all essential parts of their organization show them to be really closely allied¹⁸. They appear like actors or masqueraders dressed up and painted for amusement, or like swindlers endeavouring to pass themselves off for well-known and respectable members of society. What is the meaning of this strange travestie? Does Nature descend¹⁹ to imposture²⁰ or masquerade? We answer, she does not. Her principles are too severe. There is a use in every detail of her handiwork. The resemblance of one animal to another is of exactly the same essential nature as the resemblance to a leaf, or to bark, or to desert sand, and answers exactly the same purpose. In the one case the enemy will not attack the leaf or the bark, and so the disguise is a safeguard; in the other case it is found that for various reasons the creature resembled is passed over, and not attacked by the usual enemies of its order, and thus the creature that resembles it has an equally effectual safeguard. We are plainly shown that the disguise is of the same nature in the two cases, by the occurrence in the same group of one species resembling a vegetable substance, while another resembles a living animal of another group; and we know that the creatures resembled, possess an immunity²¹ from attack, by their being always very abundant, by their being conspicuous and not concealing themselves, and by their having generally no visible means of escape from their enemies; while, at the same time, the particular quality that makes them disliked is often very clear, such as a nasty taste or an indigestible hardness. Further examination reveals the fact that, in several cases of both kinds of disguise, it is the female only that is thus disguised; and as it can be shown that the female needs protection much more than the male, and that her preservation²² for a much longer period is absolutely necessary for the continuance of the race, we have an additional indication that the resemblance is in all cases subservient²³ to a great purpose — the preservation of the species.

In endeavouring to explain these phenomena as having been brought about by variation and natural selection, we start with the fact that white varieties frequently occur, and when protected from enemies show no incapacity for continued existence and increase. We know, further, that varieties of many other tints²⁴ occasionally occur; and as “the survival of the fittest” must inevitably²⁵ weed out those whose colours are prejudicial and preserve those whose colours are a safeguard, we require no other mode of accounting²⁶ for the protective tints of arctic and desert animals. But this being granted, there is such a perfectly²⁷ continuous and graduated series of examples of every kind of protective imitation, up to the most wonderful cases of what is termed “mimicry,” that we can find no place at which to draw the line, and say — so far variation and natural selection will account for the phenomena, but for all the rest we require a more potent²⁸ cause. The counter theories that have been proposed, that of the “special creation” of each imitative form, that of the action of “similar conditions of existence” for some of the cases, and of the laws of “hereditary descent and the reversion to ancestral forms” for others — have all been shown to be beset²⁹ with difficulties, and the two latter to be directly contradicted by some of the most constant and most remarkable³⁰ of the facts to be accounted for.

1 conceal   

v.隐藏，隐瞒，隐蔽

参考例句：

• He had to conceal his identity to escape the police.为了躲避警方，他只好隐瞒身份。
• He could hardly conceal his joy at his departure.他几乎掩饰不住临行时的喜悦。

2 concealing   

v.隐藏，隐瞒，遮住( conceal的现在分词 )

参考例句：

• Despite his outward display of friendliness, I sensed he was concealing something. 尽管他表现得友善，我还是感觉到他有所隐瞒。 来自《简明英汉词典》
• SHE WAS BREAKING THE COMPACT, AND CONCEALING IT FROM HIM. 她违反了他们之间的约定，还把他蒙在鼓里。 来自英汉文学 - 三万元遗产

3 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。

4 equilibrium   

n.平衡，均衡，相称，均势，平静

参考例句：

• Change in the world around us disturbs our inner equilibrium.我们周围世界的变化扰乱了我们内心的平静。
• This is best expressed in the form of an equilibrium constant.这最好用平衡常数的形式来表示。

5 lengthy   

adj.漫长的，冗长的

参考例句：

• We devoted a lengthy and full discussion to this topic.我们对这个题目进行了长时间的充分讨论。
• The professor wrote a lengthy book on Napoleon.教授写了一部有关拿破仑的巨著。

6 recapitulate   

v.节述要旨，择要说明

参考例句：

• Let's recapitulate the main ideas.让我们来概括一下要点。
• It will be helpful to recapitulate them.在这里将其简要重述一下也是有帮助的。

7 dwellers   

n.居民，居住者( dweller的名词复数 )

参考例句：

• City dwellers think country folk have provincial attitudes. 城里人以为乡下人思想迂腐。 来自《简明英汉词典》
• They have transformed themselves into permanent city dwellers. 他们已成为永久的城市居民。 来自《简明英汉词典》

8 reptiles   

n.爬行动物，爬虫( reptile的名词复数 )

参考例句：

• Snakes and crocodiles are both reptiles. 蛇和鳄鱼都是爬行动物。 来自《简明英汉词典》
• Birds, reptiles and insects come from eggs. 鸟类、爬虫及昆虫是卵生的。 来自《现代汉英综合大词典》

9 tinted   

adj. 带色彩的 动词tint的过去式和过去分词

参考例句：

• a pair of glasses with tinted lenses 一副有色镜片眼镜
• a rose-tinted vision of the world 对世界的理想化看法

10 thereby   

adv.因此，从而

参考例句：

• I have never been to that city,,ereby I don't know much about it.我从未去过那座城市，因此对它不怎么熟悉。
• He became a British citizen,thereby gaining the right to vote.他成了英国公民，因而得到了投票权。

11 concealed   

a.隐藏的，隐蔽的

参考例句：

• The paintings were concealed beneath a thick layer of plaster. 那些画被隐藏在厚厚的灰泥层下面。
• I think he had a gun concealed about his person. 我认为他当时身上藏有一支枪。

12 twigs   

细枝，嫩枝( twig的名词复数 )

参考例句：

• Some birds build nests of twigs. 一些鸟用树枝筑巢。
• Willow twigs are pliable. 柳条很软。

13 peculiar   

adj.古怪的，异常的；特殊的，特有的

参考例句：

• He walks in a peculiar fashion.他走路的样子很奇特。
• He looked at me with a very peculiar expression.他用一种很奇怪的表情看着我。

14 deception   

n.欺骗，欺诈；骗局，诡计

参考例句：

• He admitted conspiring to obtain property by deception.他承认曾与人合谋骗取财产。
• He was jailed for two years for fraud and deception.他因为诈骗和欺诈入狱服刑两年。

15 concealment   

n.隐藏, 掩盖，隐瞒

参考例句：

• the concealment of crime 对罪行的隐瞒
• Stay in concealment until the danger has passed. 把自己藏起来，待危险过去后再出来。

16 phenomena   

n.现象

参考例句：

• Ade couldn't relate the phenomena with any theory he knew.艾德无法用他所知道的任何理论来解释这种现象。
• The object of these experiments was to find the connection,if any,between the two phenomena.这些实验的目的就是探索这两种现象之间的联系，如果存在着任何联系的话。

17 conspicuous   

adj.明眼的，惹人注目的；炫耀的，摆阔气的

参考例句：

• It is conspicuous that smoking is harmful to health.很明显，抽烟对健康有害。
• Its colouring makes it highly conspicuous.它的色彩使它非常惹人注目。

18 allied   

adj.协约国的；同盟国的

参考例句：

• Britain was allied with the United States many times in history.历史上英国曾多次与美国结盟。
• Allied forces sustained heavy losses in the first few weeks of the campaign.同盟国在最初几周内遭受了巨大的损失。

19 descend   

vt./vi.传下来，下来，下降

参考例句：

• I hope the grace of God would descend on me.我期望上帝的恩惠。
• We're not going to descend to such methods.我们不会沦落到使用这种手段。

20 imposture   

n.冒名顶替，欺骗

参考例句：

• Soiled by her imposture she remains silent.她背着冒名顶替者的黑锅却一直沉默。
• If they knew,they would see through his imposture straight away.要是他们知道，他们会立即识破他的招摇撞骗行为。

21 immunity   

n.优惠；免除；豁免，豁免权

参考例句：

• The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
• He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。

22 preservation   

n.保护，维护，保存，保留，保持

参考例句：

• The police are responsible for the preservation of law and order.警察负责维持法律与秩序。
• The picture is in an excellent state of preservation.这幅画保存得极为完好。

23 subservient   

adj.卑屈的，阿谀的

参考例句：

• He was subservient and servile.他低声下气、卑躬屈膝。
• It was horrible to have to be affable and subservient.不得不强作欢颜卖弄风骚，真是太可怕了。

24 tints   

色彩( tint的名词复数 )； 带白的颜色； （淡色）染发剂； 痕迹

参考例句：

• leaves with red and gold autumn tints 金秋时节略呈红黄色的树叶
• The whole countryside glowed with autumn tints. 乡间处处呈现出灿烂的秋色。

25 inevitably   

adv.不可避免地；必然发生地

参考例句：

• In the way you go on,you are inevitably coming apart.照你们这样下去，毫无疑问是会散伙的。
• Technological changes will inevitably lead to unemployment.技术变革必然会导致失业。

26 accounting   

n.会计，会计学，借贷对照表

参考例句：

• A job fell vacant in the accounting department.财会部出现了一个空缺。
• There's an accounting error in this entry.这笔账目里有差错。

27 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。

28 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

29 beset   

v.镶嵌；困扰，包围

参考例句：

• She wanted to enjoy her retirement without being beset by financial worries.她想享受退休生活而不必为金钱担忧。
• The plan was beset with difficulties from the beginning.这项计划自开始就困难重重。

30 remarkable   

adj.显著的，异常的，非凡的，值得注意的

参考例句：

• She has made remarkable headway in her writing skills.她在写作技巧方面有了长足进步。
• These cars are remarkable for the quietness of their engines.这些汽车因发动机没有噪音而不同凡响。