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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viii 페이지
... by changes of climate and of the level of the land , and by occasional means - Dispersal during the Glacial period 346-382 co - extensive with the world .. CONTENTS . ix CHAPTER XII . GEOGRAPHICAL DISTRIBUTION - continued. viii CONTENTS .
... by changes of climate and of the level of the land , and by occasional means - Dispersal during the Glacial period 346-382 co - extensive with the world .. CONTENTS . ix CHAPTER XII . GEOGRAPHICAL DISTRIBUTION - continued. viii CONTENTS .
30 페이지
... land or mountain pasture , with the wool of one breed good for one purpose , and that of another breed for another purpose ; when we compare the many breeds of dogs , each good for man in very different ways ; when we compare the game ...
... land or mountain pasture , with the wool of one breed good for one purpose , and that of another breed for another purpose ; when we compare the many breeds of dogs , each good for man in very different ways ; when we compare the game ...
42 페이지
... land plays a part . Wandering savages or the inhabitants of open plains rarely possess more than one breed of the same species . Pigeons can be mated for life , and this is a great convenience to the fancier , for thus many races may be ...
... land plays a part . Wandering savages or the inhabitants of open plains rarely possess more than one breed of the same species . Pigeons can be mated for life , and this is a great convenience to the fancier , for thus many races may be ...
48 페이지
... land , I was much struck how entirely vague and arbi- trary is the distinction between species and varieties . On the islets of the little Madeira group there are many insects which are characterized as varieties in Mr. Wollaston's ...
... land , I was much struck how entirely vague and arbi- trary is the distinction between species and varieties . On the islets of the little Madeira group there are many insects which are characterized as varieties in Mr. Wollaston's ...
52 페이지
... land - shells in Madeira . If a variety were to flourish so as to exceed in numbers the parent species , it would then rank as the species , and the spe- cies as the variety ; or it might come to supplant and exterminate the parent ...
... land - shells in Madeira . If a variety were to flourish so as to exceed in numbers the parent species , it would then rank as the species , and the spe- cies as the variety ; or it might come to supplant and exterminate the parent ...
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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