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 70
... proportion to its usefulness . In fact , it is a most exagger- ated structure , often becoming closely coiled on account of its extreme length . One would sup- pose that this would be the first structure eliminated , or at least ...
... proportion to its usefulness . In fact , it is a most exagger- ated structure , often becoming closely coiled on account of its extreme length . One would sup- pose that this would be the first structure eliminated , or at least ...
Сторінка 81
... proportion ; traits which we may safely suppose to be of more recent origin than the ordinary characters marking off species within the group . Illustrations of geminate species of birds , mammals , fishes , reptiles , snails ...
... proportion ; traits which we may safely suppose to be of more recent origin than the ordinary characters marking off species within the group . Illustrations of geminate species of birds , mammals , fishes , reptiles , snails ...
Сторінка 126
... proportion of them , which may indicate one of two things ; either that there are differences . between the eggs in their capacity for modification , or that only certain eggs were in the proper stage for modification , at the time of ...
... proportion of them , which may indicate one of two things ; either that there are differences . between the eggs in their capacity for modification , or that only certain eggs were in the proper stage for modification , at the time of ...
Сторінка 146
... proportions of the offspring . He framed in general terms a state- ment of what those proportions are and advanced a simple hypothesis to account for them . Men- del's generalization we know to - day as Mendel's law , and his hypothesis ...
... proportions of the offspring . He framed in general terms a state- ment of what those proportions are and advanced a simple hypothesis to account for them . Men- del's generalization we know to - day as Mendel's law , and his hypothesis ...
Сторінка 149
... proportion three black to one brown . We thus learn that black is a unit character . It was contributed by one par ... proportions in which the individuals occur in these classes . The point may be made clearer by following through a ...
... proportion three black to one brown . We thus learn that black is a unit character . It was contributed by one par ... proportions in which the individuals occur in these classes . The point may be made clearer by following through a ...
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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...