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 viii
... single species On simultaneous changes in the forms of life throughout the world - On the affinities of extinct species to each other and to living species - On the state of development of ancient forms On the succession of the same ...
... single species On simultaneous changes in the forms of life throughout the world - On the affinities of extinct species to each other and to living species - On the state of development of ancient forms On the succession of the same ...
Página 2
... single point is discussed in this volume on which facts cannot be adduced , often apparently leading to conclusions directly opposite to those at which I have arrived . A fair result can be obtained only by fully stating and balancing ...
... single point is discussed in this volume on which facts cannot be adduced , often apparently leading to conclusions directly opposite to those at which I have arrived . A fair result can be obtained only by fully stating and balancing ...
Página 9
... single bud or offset , which suddenly assumes a new and sometimes very different character from that of the rest of the plant . 10 VARIATION Such buds can be propagated by grafting ,. B 3 CHAP . I. 9 UNDER DOMESTICATION . this curious ...
... single bud or offset , which suddenly assumes a new and sometimes very different character from that of the rest of the plant . 10 VARIATION Such buds can be propagated by grafting ,. B 3 CHAP . I. 9 UNDER DOMESTICATION . this curious ...
Página 11
... single domestic animal can be named which has not in some country drooping ears ; and the view suggested by some authors , that the drooping is due to the disuse of the muscles of the ear , from the animals not being much alarmed by ...
... single domestic animal can be named which has not in some country drooping ears ; and the view suggested by some authors , that the drooping is due to the disuse of the muscles of the ear , from the animals not being much alarmed by ...
Página 14
... intercrossing , that only a single variety should be turned loose in its new home . Nevertheless , as our varieties certainly do occasionally revert in some of their characters to ancestral forms ,. 14 CHAP . I. VARIATION.
... intercrossing , that only a single variety should be turned loose in its new home . Nevertheless , as our varieties certainly do occasionally revert in some of their characters to ancestral forms ,. 14 CHAP . I. VARIATION.
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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