On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeJ. Murray, 1860 - 502페이지 "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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5 페이지
... sometimes varying conditions of life , will have a better chance of surviving , and thus be naturally selected . From the strong principle of inheritance , any selected variety will tend to propagate its new and modified form . This ...
... sometimes varying conditions of life , will have a better chance of surviving , and thus be naturally selected . From the strong principle of inheritance , any selected variety will tend to propagate its new and modified form . This ...
9 페이지
... 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 subject; but to show how singular the ...
... 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 subject; but to show how singular the ...
10 페이지
... sometimes by seed . These " sports " are extremely rare under nature , but far from rare under cultivation ; and in this case we see that the treatment of the parent has affected a bud or offset , and not the ovules or pollen . But it ...
... sometimes by seed . These " sports " are extremely rare under nature , but far from rare under cultivation ; and in this case we see that the treatment of the parent has affected a bud or offset , and not the ovules or pollen . But it ...
13 페이지
... sometimes inherited and sometimes not so ; why the child often reverts in certain characters to its grand- father or grandmother or other more remote ancestor ; why a peculiarity is often transmitted from one sex to both sexes , or to ...
... sometimes inherited and sometimes not so ; why the child often reverts in certain characters to its grand- father or grandmother or other more remote ancestor ; why a peculiarity is often transmitted from one sex to both sexes , or to ...
20 페이지
... sometimes ( as I have found with pigeons ) extremely uniform , and everything seems simple enough ; but when these mongrels are crossed one with another for several generations , hardly two of them will be alike , and then the extreme ...
... sometimes ( as I have found with pigeons ) extremely uniform , and everything seems simple enough ; but when these mongrels are crossed one with another for several generations , hardly two of them will be alike , and then the extreme ...
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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