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
51
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】______
【1】
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
outline
解析
转载请注明原文地址:https://kaotiyun.com/show/er4O777K
0
专业英语八级
相关试题推荐
我喜爱湖。湖是大地的眼睛,湖是一种流动的深情,湖是生活中没有被剥夺的一点奇妙。早在幼年时候,一见到北海公园的太液池,我就眼睛一亮。在贫穷和危险的旧社会,太液池是一个意外的惊喜,是一种奇异的温柔,是一种孩提式的敞露与清流。我常常认为,大地与人之间有
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeveryoneonamassbasisorfindthegiftedfewandt
Ifitwereonlynecessarytodecidewhethertoteachelementarysciencetoeveryoneonamassbasisorfindthegiftedfewandt
偶然也会有一座小岛出现在地平线上,我们不知其名,但它却给人以神秘之感,那是海底峰峦的顶部,孤独、凄凉、无瑕、偏僻地矗立在海上。人们喜爱岛屿,是否因为在这难以驾驭的广大世界里有这样一小块易于管理的领地,人们就不知不觉地要据为己有?我想到那座岛屿一直就在那里
MannersnowadaysinmetropolitancitieslikeLondonarepracticallynon-existent.Itisnothingforabig,strongschoolboytoe
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
在洛杉矶,一位美国朋友开车带我去看富人区。富人区就是有钱人的聚居地。美国人喜欢陪客人看富人区,好似观光。在我面前是千姿百态的房子和庭院,优雅、宁静、舒适,真如人间天堂。我忽然有个问题问他:“你们看到富人们住在这么漂亮的房子里,会不会嫉妒?”我这位
Itiswellthatthecommonestfruitshouldbealsothebest.OfthevirtuesoftheorangeIhavenotroomfullytospeak.Ithas
Peopletendtostrugglewhenlearninganotherlanguage,especiallyiftheyareexposedonlyitwhileattendingclasses.【M1】_____
随机试题
栓剂研制中应考虑
下列属于母婴保健法规定可以申请医学技术鉴定的是
A.极化B.去极化C.复极化D.超极化E.反极化
关于股票价格指数期货论述不正确的是( )。
下列关于依法收贷应注意的几个问题中,正确的是()。
商务谈判的模式包括()。
下列不具有法人资格的是()。
甲、乙、丙、丁四个同学排成一排,从左往右数,如果甲不排在第一个位置上,乙不排在第二个位置上,丙不排在第三个位置上,丁不排在第四个位置上,那么不同的排法共有()种。
PragmatismisaphilosophicalmovementthathashadamajorimpactonAmericanculturefromthelate19thcenturytothepresent
(1)Mostpeoplehaveexperiencedthefeeling,afterataxingmentalwork-out,thattheycannotbebotheredtomakeanymoredecis
最新回复
(
0
)