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acquired characters adaptive characters adduced admit animals appears argument argument from ignorance artificial selection become cause cessation of selection chapter climatic co-adaptation colour concerned congenital connexion continuity correlation Darwin Darwinian deduction definition degeneration degree distinction disuse doctrine due to natural epilepsy evidence experiments explain fact favour force of heredity Galton genera germ-plasm hereditary importance individuals inherited effects instincts kind Lamarck Lamarckian factors Lamarckian principles large proportional number less Lloyd Morgan matter merely modifications natural selection naturalists necessarily niata observed occur opinion organic evolution Origin of Species pangenesis panmixia particular peculiar plants possible present produced Professor Weismann progeny prove question reason reflex action reflex mechanism regard remark restiform body reversal of selection sciatic nerve sexual selection somatogenetic specific characters statement structure sufficient suppose theory of heredity theory of natural tion transmission of acquired transmitted use-inheritance utility variations varieties Wallace Wallace's Weismann's theory
Page 314 - I did not formerly consider sufficiently the existence of structures, which, as far as we can at present judge, are neither beneficial nor injurious; and this I believe to be one of the greatest oversights as yet detected in my work.
Page 4 - I have now recapitulated the facts and considerations which have thoroughly convinced me that species have been modified during a long course of descent. This has been effected chiefly through the natural selection of numerous successive, slight, favourable variations; aided in an important manner by the inherited effects of the use and disuse of parts; and in an unimportant manner, that is in relation to adaptive structures, whether past or present, by the direct action of external conditions, and...
Page 319 - The sutures in the skulls of young mammals have been advanced as a beautiful adaptation for aiding parturition, and no doubt they facilitate, or may be indispensable for this act; but as sutures occur in the skulls of young birds and reptiles, which have only to escape from a broken egg, we may infer that this structure has arisen from the laws of growth, and has been taken advantage of in the parturition of the higher animals.
Page 5 - Species, p. 176. favourable variations ; aided in an important manner by the inherited effects of the use and disuse of parts ; and in an unimportant manner, that is in relation to adaptive structures, whether past or present, by the direct action of external conditions, and by variations which seem to us in our ignorance to arise spontaneously.
Page 5 - ... selection. But as my conclusions have lately been much misrepresented, and it has been stated that I attribute the modification of species exclusively to natural selection, I may be permitted to remark that in the first edition of this work, and subsequently, I placed in a most conspicuous position — namely, at the close of the Introduction the following words : "I am convinced that natural selection has been the main but not the exclusive means of modification.
Page 105 - I have seen the transmission of the morbid state of the eye continue through four generations. In these animals modified by heredity, the two eyes generally protruded, although in the parents usually only one showed exophthalmia, the lesion having been made in most cases only on one of the corpora restiformia. "
Page 27 - The special faculties we have been discussing clearly point to the existence in man of something which he has not derived from his animal progenitors — something which we may best refer to as being of a spiritual essence or nature, capable of progressive development under favorable conditions.
Page 193 - ... but during the great droughts, when so many animals perish, the niata breed is under a great disadvantage, and would be exterminated if not attended to; for the common cattle, like horses, are able just to keep alive, by browsing with their lips on twigs of trees and reeds; this the niatas cannot so well do, as their lips do not join, and hence they are found to perish before the common cattle. This strikes me as a good illustration of how little we are able to judge from the ordinary habits...
Page 4 - When discussing special cases, Mr. Mivart passes over the effects of the increased use and disuse of parts, which I have always maintained to be highly important, and have treated in my ' Variation under Domestication ' at greater length than, as I believe, any other writer.