Fifty Years of Darwinism: Modern Aspects of Evolution; Centennial Addresses in Honor of Charles Darwin, Before the American Association for the Advancement of Science, Baltimore, Friday, January 1, 1909H. Holt, 1909 - 274 стор. |
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Сторінка 76
... colors of the ani- mals . All these variations , too small to justify the use of technical names , form the beginnings of difference in subspecies . With more perfect isolation these characters would soon assume greater importance ...
... colors of the ani- mals . All these variations , too small to justify the use of technical names , form the beginnings of difference in subspecies . With more perfect isolation these characters would soon assume greater importance ...
Сторінка 108
... color by specific and separable factors , the production of particular colors by mixing to- gether factors which are singly incapable of pro- ducing color — in all this we see a series of oper- ations that show an astonishing similarity ...
... color by specific and separable factors , the production of particular colors by mixing to- gether factors which are singly incapable of pro- ducing color — in all this we see a series of oper- ations that show an astonishing similarity ...
Сторінка 125
... , that the eggs thus treated , when fertilized by normal male germs , gave the form shown , which breeds true without subsequent segregation of charac- ters . In this case both structural and color char- OF ENVIRONMENT 125.
... , that the eggs thus treated , when fertilized by normal male germs , gave the form shown , which breeds true without subsequent segregation of charac- ters . In this case both structural and color char- OF ENVIRONMENT 125.
Сторінка 126
... color char- acters are modified . " Many other illustrations might be given of the entire change in the coloration of body , both in larvæ or adult , of the modifications of parts and of particular portions of the body or of individual ...
... color char- acters are modified . " Many other illustrations might be given of the entire change in the coloration of body , both in larvæ or adult , of the modifications of parts and of particular portions of the body or of individual ...
Сторінка 141
... color , or it may be taken as a differentiation in advance . 6. The behavior of the newly derived forms when subjected to natural conditions , competi- tion , and possibility of hybridization with paren- tal forms , has been extremely ...
... color , or it may be taken as a differentiation in advance . 6. The behavior of the newly derived forms when subjected to natural conditions , competi- tion , and possibility of hybridization with paren- tal forms , has been extremely ...
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Загальні терміни та фрази
acquired characters acters adapted faunas albinos American animals appearance arise arisen Asa Gray beetles biological birds blind fishes brachycephaly breed causes cave changes of proportion char Characins Charles Darwin chromatin chromosomes color crossed cusps Darwin Darwinian direction discontinuous dolichocephaly effects eggs elements eliminated environment Eocene evidence evolution existence experiments fact factors Francis Darwin fresh water genus germ-cells germ-plasm germinal gray Gymnosperms hereditary heredity Homoplasy horns Horse Cave hypothesis individual intergrades isolation Lamarckian large number less Letters Lyell mammals Mendel ment modification muta mutation Nägeli Natural Selection naturalist observation ontogeny organs origin of adaptations Origin of Species orthogenesis Osborn ovaries paleontology pangenesis parent phyla pigment plants present principle produced protoplasm quantitative question rabbits rectigradations relation reproductive cells seed soma somatic sooty structure tain tation teeth theory tion titanotheres transmission unit characters variations Vries Waagen Weismann yellow zoologist
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Сторінка 14 - but no. From scarped cliff and quarried stone She cries " A thousand types are gone : I care for nothing, all shall go.
Сторінка 206 - These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction ; Variability from the indirect and direct action of the external conditions of life, and from use and disuse...
Сторінка 207 - These laws, taken in the largest sense being Growth with Reproduction; Inheritance which is almost implied by reproduction; Variability from the indirect and direct action of the conditions of life and from use and disuse; a Ratio of Increase so high as to lead to a struggle for Life, and as a consequence to Natural Selection, entailing Divergence of Character and the Extinction of less-improved forms. Thus from the war of nature, from famine and death, the most exalted object which we are capable...
Сторінка 73 - Given any species in any region, the nearest related species is not likely to be found in the same region nor in a remote region, but in a neighboring district separated from the first by a barrier of some sort, or at least by a belt of country, the breadth of which gives the effect of a barrier.
Сторінка 11 - All which seem to have been gradually produced during many generations by the perpetual endeavour of the creatures to supply the want of food, and to have been delivered to their posterity with constant improvement of them for the purposes required.
Сторінка 13 - I can without saying so in so many words —for I have always thought that the great merit of the Principles was that it altered the whole tone of one's mind...
Сторінка 12 - For consistent uniformitarianism postulates evolution as much in the organic as in the inorganic world. The origin of a new species by other than ordinary agencies would be a vastly greater " catastrophe " than any of those which Lyell successfully eliminated from sober geological speculation.
Сторінка 16 - It was, very briefly, that there had been no gradual modification of the surface of the earth, or slow development of organic forms, but that when the catastrophic act of creation took place, the world presented, instantly, the structural appearance of a planet on which life had long existed.
Сторінка 22 - I have read your book with more pain than pleasure. Parts of it I admired greatly, parts I laughed at till my sides were almost sore ; other parts I read with absolute sorrow, because I think them utterly false and grievously mischievous. You have deserted — after a start in that tram-road of all solid physical truth — the true method of induction, and started us in machinery as wild, I think, as Bishop Wilkins's locomotive that was to sail with us to the moon.
Сторінка 20 - I was then (as often since) the "young man in a hurry"; he, the painstaking and patient student, seeking ever the full demonstration of the truth that he had discovered, rather than to achieve immediate personal fame. Such being the actual facts of the case, I should have had no cause for complaint if the respective shares of Darwin and myself in regard to the elucidation of nature's method of organic development had been thenceforth estimated as being, roughly, proportional to the time we had each...