首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Cryptic Coloring Cryptic coloring is by far the commonest use of color in the struggle for existence. It is employed for the
Cryptic Coloring Cryptic coloring is by far the commonest use of color in the struggle for existence. It is employed for the
admin
2011-03-10
38
问题
Cryptic Coloring
Cryptic coloring is by far the commonest use of color in the struggle for existence. It is employed for the purpose of attack as well as of defense, and may be either general or special.
Ⅰ. General resemblance:
It’s especially common among the animal inhabiting some
uniformly colored expanse of【1】, such as an ocean or a desert: 【1】______
1) Animals are often【2】by their transparent 【2】______
blue color or sandy appearance.
2) Equally diverse forms are defended by their sandy appearance.
Ⅱ. Special resemblance:
It’s far commoner than general, and usually met with:
1) on the diversified surface of the earth; 2)on the shores;
3) in【3】water; 4)on the surface of the ocean. 【3】______
The【4】of coloring, shape, and attitude produces a more 【4】______
or less exact resemblance to some one of【5】in the environment. 【5】______
Ⅲ. The attempts have been made along two lines for the
【6】of these most interesting and elaborate adaptations: 【6】______
1) The first explans:
Effect is a result of the direct influence of the environment
upon【7】, or by the inherited effects of efforts and 【7】______
the【8】of parts. 【8】______
2) The second believes:
【9】produced the result and afterwards maintained it 【9】______
by the survival of the best concealed in each generation.
In the present state of science, the only possible hole
of an interpretation【10】the theory of natural selection. 【10】______
【8】
Cryptic Coloring
Good morning, we are going to talk about cryptic coloring today.
Cryptic coloring is by far the commonest use of color in the struggle for existence. It is employed for the purpose of attack (aggressive resemblance or anticryptic coloring ) as well as of defense (protective resemblance or procryptic coloring ). The fact that the same method concealment, may be used both for attack and defense has been Well explained by T. Belt, who suggests as an illustration the rapidity of movement which is also made use of by both pursuer and pursued, which is similarly raised to a maximum in both by the gradual dying out of the slowest through a series of generations. Cryptic coloring is commonly associated with other aids in the struggle for life. Thus well-concealed mammals and birds, when discovered, will generally endeavor to escape by speed and will often attempt to defend themselves actively. On the other hand, small animals which have no means of active defense, such as large numbers of insects, frequently depend upon concealment alone. Protective resemblance is far commoner among animals than aggressive resemblance, in correspondence with the fact that predaceous forms are as a rule much larger and much less numerous than their prey. in the case of insectivorous vertebrata and their prey such differences exist in an exaggerated form. Cryptic coloring, whether used for defense of attack, may be either general or special. In general resemblance the animal, in consequence of its coloring, produces the same effect as its environment, but the conditions do not require any special adaptation of shape and outline. General resemblance is especially common among the animal inhabiting some uniformly colored expanse of the earth’s surface, such as an ocean or a desert. In the former, animals of all shapes are frequently protected by their transparent blue color, on the latter, equally diverse forms are defended by their sandy appearance. The effect of a uniform appearance may be produced by a combination of tints in startling contrast. Thus the black and white stripes of the zebra blend together at a little distance, and "their proportion is such as exactly to match the pale tint which arid ground possesses when seen by moonlight." Special resemblance is far commoner than general and is the form which is usually met with on the diversified surface of the earth, on the shores, and in shallow water, as well as on the floating masses of algae on the surface of the ocean, such as the Sargasso Sea. In these environments the cryptic coloring of animals is usually aided by special modifications of shape, and by the instinct which leads them to assume particular attitudes. Complete stillness and the assumption of a certain attitude play an essential part in general resemblance on land; but in special resemblance the attitude is often highly specialized, and perhaps more important than any other element in the complex method by which concealment is effected. In special resemblance the combination of coloring, shape, and attitude is such as to produce a more or less exact resemblance to some one of the objects in the environment, such as a leaf of twig, a patch of lichen, a flake of bark. In all cases the resemblance is to some object which is of no interest to the enemy or prey respectively. The animal is not hidden from view by becoming indistinguishable from its background as in the case of general resemblance, but it is mistaken for some well-know object.
In seeking the interpretation of these most interesting and elaborate adaptations, attempts have been made along two lines. The first seeks to explain the effect as a result of the direct influence of the environment upon the individual (G.L.L.Buffon), or by the inherited effects of efforts and the use and disuse of parts (J.B.RLamarck). The second believes that natural selection produced the result and afterwards maintained it by the survival of the best concealed in each generation. The former suggestion breaks down when the complex nature of numerous special resemblances is appreciated. Thus the arrangement of colors of many kinds into an appropriate pattern requires the cooperation of a suitable shape and the rigidly exact adoption of a certain elaborate attitude. The latter is instinctive and thus depends on the central nervous system. The cryptic effect is due to the exact cooperation of all these factors; and in the present state of science, the only possible hole of an interpretation lies in the theory of natural selection, which can accumulate any and every variation which tends toward survival. A few of the chief types of methods by which concealment is effected may be briefly described. The colors of large numbers of vertebrate animals are darkest on the back and become gradually lighter on the sides, passing into white on the belly. Abbot H. Thayer has suggested that this gradation obliterates the appearance of solidity, which is due to shadow. The color harmony, which is also essential to concealment, is produced because the back is of the same tint as the environment (e. g. earth), bathed in the cold blue-white of the sky, while the belly, being cold blue-white and bathed in shadow and yellow earth reflections produces the same effects. This method of neutralizing shadow for the purpose of concealment by increased lightness of tint was first suggested by E.B.Poulton in the case of a larva and a pupa, but he did not appreciate the great importance of the principle. In an analogous method an animal in front of a background of dark shadow may have part of its body obliterated by the existence of a dark tint, the remainder resembling, e.g., a part of a leaf. This method of rendering invisible any part which would interfere with the resemblance is well know in mimicry.
选项
答案
use and disuse
解析
转载请注明原文地址:https://www.kaotiyun.com/show/TDYO777K
0
专业英语八级
相关试题推荐
TheAmericanCivilWarbrokeoutin______.
Sinceabout1950,publictransportationintheU.S.hashadtostruggletosurvive.Thegrowthofprivateautomobileownership,
Rabiesisanordinarilyinfectiousdiseaseofthecentralnervoussystem,causedbyavirusand,asarule,spreadchieflybydo
Transformational-generativegrammar(TG)isof______’sgreatcontributiontolinguisticsdevelopment.
CrypticColoringCrypticcoloringisbyfarthecommonestuseofcolorinthestruggleforexistence.Itisemployedforthe
______looksatlanguagefromapsychologicalpointofview,andtohim,competenceisapropertyofthemindofeachindividual
Likeallanimalspecies,plantspeciesmustspreadtheiroffspringtosuitableareaswheretheycangrowandpassontheirparen
AlongpainfulstrugglewithcancerandchemotherapyhadcausedbaldnessforBarbaraBassett,ofMoorstown,N.J.Thedayherblo
外来移民难道真的是欧洲社会难以摆脱的失业和高犯罪率的罪魁祸首吗?今天的欧洲或许算是一方乐土,吸引着非洲、亚洲、南美洲的许多年轻人背井离乡到这里来谋生求发展。更重要的是,西欧今天已经离不开移民。移民的到来对欧洲的经济社会发展,甚至改善欧洲人口年龄结构,起着不
随机试题
下列关于简易程序说法错误的是:()
(当谈到细节时)heisverycareful.
男,5岁,平素健康,4天来高热,寒战咳嗽伴右侧胸痛,胸片提示右下肺片状影伴右侧中等量胸腔积液。关于胸腔穿刺的目的正确的是
下列关于涉外民事诉讼的表述,哪些符合民事诉讼法的规定?
下列关于营业税的相关陈述,不正确的是( )。
根据社会保险法律制度的规定,职工发生的下列情形中,不认定为工伤的有()。
王凯是一个对上网非常痴迷的孩子。他爸爸由于工作需要买了一台电脑在家中上网,起初他同爸爸一起玩,父母也没有表示反对。到后来,他发展到每天起床后就去上网,连中午、晚上休息时间也不放过。王凯俨然成了一个名副其实的“网虫”。沉迷于互联网上的紧张、激烈的游戏和无拘无
某市出租车司机要求降低税费等而发生罢运事件。出租车行业协会辞退了参与罢运的46名司机,并对他们处以终身停运的处罚。你认为这种做法是否妥当,谈谈你对这件事的看法?如果你负责这件事情,你会如何处理?
(13)矩阵相似的充分必要条件为
某二叉树中度为2的节点有n个,则该二叉树中有______个叶子节点。
最新回复
(
0
)