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 the commonest use of color in the struggle for existence. Ⅰ Cryptic coloring, may be ei
Cryptic Coloring Cryptic coloring is the commonest use of color in the struggle for existence. Ⅰ Cryptic coloring, may be ei
admin
2013-06-12
46
问题
Cryptic Coloring
Cryptic coloring is the commonest use of color in the struggle for existence.
Ⅰ Cryptic coloring, may be either general or special.
General
1) In general resemblance the animal through its coloring, produces the same
effect as its environment, but no special adaptation of shape and【1】______ 【1】______
is required.
2) General resemblance is commonly employed by the animal inhabiting some
uniformly colored expanse of the earth’ s surface, such as【2】______. The 【2】______
effect of a uniform appearance may be produced by a combination of tints in
startling【3】______. 【3】______
Special
Special resemblance is far commoner than the general one and is the form usually met with on the diversified surface【4】______, as well as on the floating masses of algae 【4】______
on the surface of the ocean. 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【5】______. 【5】______
Accordingly we can note that the animal tries to be
hidden from view by becoming【6】______ from its background in case of 【6】______
general resemblance while the animal tries to
be mistaken for some well-known object in case of special resemblance.
Ⅱ People have tried to explain these adaptations in two ways.
1) The first suggestion that the effect is a result of the direct influence of the
environment on the【7】______ breaks down when the complex nature of 【7】______
numerous special resemblances is【8】______ 【8】______
2) The second believes that natural selection produced the result and afterwards
maintained it by the survival of the best concealed in【9】______. The 【9】______
cryptic effect is due to the exact cooperation of many factors; and in the present state of science, the only possible hole of an interpretation lies in【10】______. 【10】______
【5】
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.P.Lamarck). 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 lint 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 pan of a leaf. This method of rendering invisible any pan which would interfere with the resemblance is well know in mimicry.
选项
答案
attitudes
解析
转载请注明原文地址:https://kaotiyun.com/show/Sr4O777K
0
专业英语八级
相关试题推荐
______meansthatlanguagecanbeusedtorefertothecontextsthatareremovedfromtheimmediatesituationofthespeaker,esp
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeveryoneonamassbasisorfindthegiftedfewandt
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeveryoneonamassbasisorfindthegiftedfewandt
ThegreatdividinglinebetweenthenineteenthcenturyandthecontemporaryAmericanLiteratureis______.
______takesLondonasthesettinginmostofhisnovels.
Literatureisameansbywhichweknowourselves.Byitwe(1)______meetfutureselves,andrecognizepastselves;againstitw
Literatureisameansbywhichweknowourselves.Byitwe(1)______meetfutureselves,andrecognizepastselves;againstitw
那还是几年前的一个早晨,在太阳刚刚升起来的时候,踏着熹微的晨光,到一个离开旅馆不远的菜市场去。到了邻近菜市场的地方,市场的气氛就逐渐浓了起来。熙熙攘攘的人群,摩肩擦背,来来往往。许多老大娘的菜篮子里装满了蔬菜海味鸡鸭鱼肉。有的篮子里活鱼在摇摆着尾巴,肥鸡在
Shewasveryhandsome,withacertainfine,richcoloringthatbelongstothehealthybrunettype.Shewasquitecomposed,assh
随机试题
论述陶行知的普及教育思想。
当前Internet网络主要使用的IP是【】
《诗经.氓》:三岁为妇,靡室劳矣。_________,靡有朝矣。
近端小管对葡萄糖重吸收的关键途径是
某药品批发企业拟根据现行的《药品经营质量管理规范》申请药品GSP换证。该药品批发企业在下列有关药品储存方面,应当做到:不符合现行《药品经营质量管理规范》的行为是()
对淹溺病人出现心脏呼吸骤停的现场急救应最先实施
城市交通调查的目的是()。
集中型风险管理部门的缺点是难以绝对控制商业银行的敏感信息,无法形成长期的核心竞争力和强大的市场定价能力。()
文明的进展并不完全像是一股奔腾直前、日趋佳境的巨流。如果我们用一种相当大的比例尺把它绘制成图,也许会具有上述外观。但这种广泛的看法往往会____________细节,而我们对这一过程的全部理解却必须____________于这种细节。假如我们从绵延几万年的
请从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性。
最新回复
(
0
)