On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeJ. Murray, 1860 - 502 páginas "In considering the Origin of Species, it is quite conceivable that a naturalist, reflecting on the mutual affinities of organic beings, on their embryological relations, their geographical distribution, geological succession, and other such facts, might come to the conclusion that each species had not been independently created, but had descended, like varieties, from other species. Nevertheless, such a conclusion, even if well founded, would be unsatisfactory, until it could be shown how the innumerable species inhabiting this world have been modified, so as to acquire that perfection of structure and coadaptation which most justly excites our admiration. Naturalists continually refer to external conditions, such as climate, food, & c, as the only possible cause of variation. In one very limited sense, as we shall hereafter see, this may be true; but it is preposterous to attribute to mere external conditions, the structure, for instance, of the woodpecker, with its feet, tail, beak, and tongue, so admirably adapted to catch insects under the bark of trees. In the case of the misseltoe, which draws its nourishment from certain trees, which has seeds that must be transported by certain birds, and which has flowers with separate sexes absolutely requiring the agency of certain insects to bring pollen from one flower to the other, it is equally preposterous to account for the structure of this parasite, with its relations to several distinct organic beings, by the effects of external conditions, or of habit, or of the volition of the plant itself"--Introduction. (PsycINFO Database Record (c) 2012 APA, all rights reserved) |
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Página 12
... Hence , if man goes on selecting , and thus augmenting , any pe- culiarity , he will almost certainly unconsciously modify other parts of the structure , owing to the mysterious laws of the correlation of growth . The result of the ...
... Hence , if man goes on selecting , and thus augmenting , any pe- culiarity , he will almost certainly unconsciously modify other parts of the structure , owing to the mysterious laws of the correlation of growth . The result of the ...
Página 14
... Hence it has been argued that no deductions can be drawn from domestic races to species in a state of nature . I have in vain endeavoured to discover on what decisive facts the above statement has so often and so boldly been made ...
... Hence it has been argued that no deductions can be drawn from domestic races to species in a state of nature . I have in vain endeavoured to discover on what decisive facts the above statement has so often and so boldly been made ...
Página 23
... Hence the supposed aboriginal stocks must either still exist in the countries where they were originally domes- ticated , and yet be unknown to ornithologists ; and this , considering their size , habits , and remarkable characters ...
... Hence the supposed aboriginal stocks must either still exist in the countries where they were originally domes- ticated , and yet be unknown to ornithologists ; and this , considering their size , habits , and remarkable characters ...
Página 24
... Hence the supposed ex- termination of so many species having similar habits with the rock - pigeon seems to me a very rash assump- tion . Moreover , the several above - named domesticated breeds have been transported to all parts of the ...
... Hence the supposed ex- termination of so many species having similar habits with the rock - pigeon seems to me a very rash assump- tion . Moreover , the several above - named domesticated breeds have been transported to all parts of the ...
Página 39
... goose has not given rise to any marked varieties ; hence the Thoulouse and the common breed , which differ only in colour , that most fleeting of characters , have lately been exhibited as. CHAP . I. 39 SELECTION BY MAN .
... goose has not given rise to any marked varieties ; hence the Thoulouse and the common breed , which differ only in colour , that most fleeting of characters , have lately been exhibited as. CHAP . I. 39 SELECTION BY MAN .
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Términos y frases comunes
adapted affinities allied species America analogous ancient animals become bees believe birds breeds cause cells chapter characters cirripedes climate closely allied colour continuous crossed crustaceans degree difficulty distinct species divergence domestic doubt embryo Europe existing exterminated extinct extremely facts favourable Fcap fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period greater number groups of species habits Hence hermaphrodites History hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing intermediate land larvæ less living male mammals manner migration modification modified descendants natural selection naturalists nearly nest offspring perfect pigeons plants pollen Portrait Post 8vo present principle probably produced progenitor racter ranked reciprocal crosses remarked resemble rudimentary organs Second Edition seeds sexual selection Silurian slight South America sterility structure struggle successive supposed theory Third Edition tion variability variations varieties vary Vols widely Woodcuts