The Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeJohn Murray, 1873 - 458페이지 |
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73 페이지
... stamens and pistils placed , in relation to the size and habits of the particular insect which visited them , so as ... stamens producing a rather small quantity of pollen , and a rudimentary pistil ; other holly - trees bear only female ...
... stamens and pistils placed , in relation to the size and habits of the particular insect which visited them , so as ... stamens producing a rather small quantity of pollen , and a rudimentary pistil ; other holly - trees bear only female ...
74 페이지
... stamens alone in one flower or on one whole plant , and pistils alone in another flower or on another plant . In plants under culture and placed under new conditions of life , sometimes the male organs and sometimes the female organs ...
... stamens alone in one flower or on one whole plant , and pistils alone in another flower or on another plant . In plants under culture and placed under new conditions of life , sometimes the male organs and sometimes the female organs ...
77 페이지
... stamens of a flower suddenly spring towards the pistil , or slowly move one after the other towards it , the contrivance seems adapted solely to ensure self - fertilisation ; and no doubt it is useful for this end : but the agency of ...
... stamens of a flower suddenly spring towards the pistil , or slowly move one after the other towards it , the contrivance seems adapted solely to ensure self - fertilisation ; and no doubt it is useful for this end : but the agency of ...
78 페이지
... stamens , but by those of the many other flowers on the same plant ; and the pollen of each flower readily gets on its own stigma without insect - agency ; for I have found that plants carefully protected from insects produce the full ...
... stamens , but by those of the many other flowers on the same plant ; and the pollen of each flower readily gets on its own stigma without insect - agency ; for I have found that plants carefully protected from insects produce the full ...
97 페이지
... which have every organ , as sepals , petals , stamens , and pistils , fully developed in each flower ; whereas other botanists , H probably with more truth , look at the plants which CHAP . IV . 97 Natural Selection .
... which have every organ , as sepals , petals , stamens , and pistils , fully developed in each flower ; whereas other botanists , H probably with more truth , look at the plants which CHAP . IV . 97 Natural Selection .
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adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continuous crossed crustaceans degree developed difficulty distinct species doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formations formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hybrids important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked reproductive resemblance rudimentary seeds sexual selection slight South America stamens sterility structure struggle successive supposed theory tion variability variations varieties vary whilst whole wings young
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1 페이지 - These facts, as will be seen in the latter chapters of this volume, seemed to throw some light on the origin of species — that mystery of mysteries, as it has been called by one of our greatest philosophers.
162 페이지 - ... if it could be proved that any part of the structure of any one species had been formed for the exclusive good of another species, it would annihilate my theory, for such could not have been produced through natural selection
1 페이지 - ... of our greatest philosophers. On my return home, it occurred to me, in 1837, that something might perhaps be made out on this question by patiently accumulating and reflecting on all sorts of facts which could possibly have any bearing on it. After five years' work I allowed myself to speculate on the subject, and drew up some short notes...
424 페이지 - Analogy would lead me one step further, namely, to the belief that all animals and plants have descended from some one prototype. But analogy may be a deceitful guide.
50 페이지 - In these several senses, which pass into each other, I use for convenience' sake the general term of Struggle for Existence.
322 페이지 - Every species has come into existence coincident both in space and time with a pre-existing closely allied species.
146 페이지 - If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down.
310 페이지 - I strongly insisted, in 1839 and 1845, on this " law of the succession of types,"—on " this wonderful relationship in the same continent between the dead and the living." Professor Owen has subsequently extended the same generalisation to the mammals of the Old World. We see the same law in this author's restorations of the extinct and gigantic birds of New Zealand. We see it also in the birds of the caves of Brazil. Mr. Woodward has shown that the same law holds good with sea-shells, but, from...
57 페이지 - Now the number of. mice is largely dependent, as every one knows, on the number of cats; and Col.
103 페이지 - It is a truly wonderful fact—the wonder of which we are apt to overlook from familiarity—that all animals and all plants throughout all time and space should be related to each other in groups subordinate to groups, in the manner which we everywhere behold...