Having thus shown how
varied1 and extraordinary are the modes in which
mimicry2 occurs among insects, we have now to
enquire3 if anything of the same kind is to be observed among vertebrated animals. When we consider all the conditions necessary to produce a good
deceptive4 imitation, we shall see at once that such can very rarely occur in the higher animals, since they possess none of those facilities for the almost infinite
modifications5 of external form which exist in the very nature of insect organization. The outer covering of insects being more or less solid and horny, they are capable of almost any amount of change of form and appearance without any essential
modification6 internally. In many groups the wings give much of the character, and these organs may be much modified both in form and colour without
interfering7 with their special functions. Again, the number of species of insects is so great, and there is such diversity of form and proportion in every group, that the chances of an accidental approximation in size, form, and colour, of one insect to another of a different group, are very considerable; and it is these chance approximations that furnish the basis of mimicry, to be continually advanced and perfected by the survival of those varieties only which tend in the right direction.
In the Vertebrata, on the contrary, the skeleton being internal the external form depends almost
entirely8 on the proportions and arrangement of that skeleton, which again is
strictly9 adapted to the functions necessary for the
well-being10 of the animal. The form cannot therefore be rapidly modified by variation, and the thin and flexible
integument11 will not admit of the development of such strange protuberances as occur continually in insects. The number of species of each group in the same country is also comparatively small, and thus the chances of that first accidental resemblance which is necessary for natural selection to work upon are much diminished. We can hardly see the possibility of a mimicry by which the
elk12 could escape from the wolf, or the
buffalo13 from the tiger. There is, however, in one group of Vertebrata such a general similarity of form, that a very slight modification, if accompanied by identity of colour, would produce the necessary amount of resemblance; and at the same time there exist a number of species which it would be
advantageous14 for others to resemble, since they are armed with the most fatal weapons of offence. We accordingly find that
reptiles15 furnish us with a very
remarkable16 and instructive case of true mimicry.
点击
收听单词发音
1
varied
|
|
adj.多样的,多变化的 |
参考例句: |
- The forms of art are many and varied.艺术的形式是多种多样的。
- The hotel has a varied programme of nightly entertainment.宾馆有各种晚间娱乐活动。
|
2
mimicry
|
|
n.(生物)拟态,模仿 |
参考例句: |
- One of his few strengths was his skill at mimicry.他为数不多的强项之一就是善于模仿。
- Language learning usually necessitates conscious mimicry.一般地说,学习语言就要进行有意识的摹仿。
|
3
enquire
|
|
v.打听,询问;调查,查问 |
参考例句: |
- She wrote to enquire the cause of the delay.她只得写信去询问拖延的理由。
- We will enquire into the matter.我们将调查这事。
|
4
deceptive
|
|
adj.骗人的,造成假象的,靠不住的 |
参考例句: |
- His appearance was deceptive.他的外表带有欺骗性。
- The storyline is deceptively simple.故事情节看似简单,其实不然。
|
5
modifications
|
|
n.缓和( modification的名词复数 );限制;更改;改变 |
参考例句: |
- The engine was pulled apart for modifications and then reassembled. 发动机被拆开改型,然后再组装起来。 来自《简明英汉词典》
- The original plan had undergone fairly extensive modifications. 原计划已经作了相当大的修改。 来自《简明英汉词典》
|
6
modification
|
|
n.修改,改进,缓和,减轻 |
参考例句: |
- The law,in its present form,is unjust;it needs modification.现行的法律是不公正的,它需要修改。
- The design requires considerable modification.这个设计需要作大的修改。
|
7
interfering
|
|
adj. 妨碍的
动词interfere的现在分词 |
参考例句: |
- He's an interfering old busybody! 他老爱管闲事!
- I wish my mother would stop interfering and let me make my own decisions. 我希望我母亲不再干预,让我自己拿主意。
|
8
entirely
|
|
ad.全部地,完整地;完全地,彻底地 |
参考例句: |
- The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
- His life was entirely given up to the educational work. 他的一生统统献给了教育工作。
|
9
strictly
|
|
adv.严厉地,严格地;严密地 |
参考例句: |
- His doctor is dieting him strictly.他的医生严格规定他的饮食。
- The guests were seated strictly in order of precedence.客人严格按照地位高低就座。
|
10
well-being
|
|
n.安康,安乐,幸福 |
参考例句: |
- He always has the well-being of the masses at heart.他总是把群众的疾苦挂在心上。
- My concern for their well-being was misunderstood as interference.我关心他们的幸福,却被误解为多管闲事。
|
11
integument
|
|
n.皮肤 |
参考例句: |
- The first protector against the entry of microorganisms is the integument.抗御微生物进入体内的第一道防线是皮肤。
- The cells of the integument and nucellus of some plants form perfectly normal embryos.某些植物的珠被和珠心细胞形成完全正常的胚。
|
12
elk
|
|
n.麋鹿 |
参考例句: |
- I was close enough to the elk to hear its labored breathing.我离那头麋鹿非常近,能听见它吃力的呼吸声。
- The refuge contains the largest wintering population of elk in the world.这座庇护所有着世界上数量最大的冬季麋鹿群。
|
13
buffalo
|
|
n.(北美)野牛;(亚洲)水牛 |
参考例句: |
- Asian buffalo isn't as wild as that of America's. 亚洲水牛比美洲水牛温顺些。
- The boots are made of buffalo hide. 这双靴子是由水牛皮制成的。
|
14
advantageous
|
|
adj.有利的;有帮助的 |
参考例句: |
- Injections of vitamin C are obviously advantageous.注射维生素C显然是有利的。
- You're in a very advantageous position.你处于非常有利的地位。
|
15
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》
|
16
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。
|