The Variation of animals and plants under domestication v. 2, Volumul 2Appleton, 1876 |
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Pagina 23
... of both parent - species exist in every hybrid in a double state , namely , blended together and com- 50 Nouvelles Archives du Muséum , ' tom . i . p . 151 . pletely separate . How this is possible , and what CHAP . XIII . 23 REVERSION .
... of both parent - species exist in every hybrid in a double state , namely , blended together and com- 50 Nouvelles Archives du Muséum , ' tom . i . p . 151 . pletely separate . How this is possible , and what CHAP . XIII . 23 REVERSION .
Pagina 26
... exist in a latent state , ready to be evolved under certain conditions . It is well known that a large number of female birds , such as fowls , various pheasants , partridges , peahens , ducks , & c . , when old or diseased , or when ...
... exist in a latent state , ready to be evolved under certain conditions . It is well known that a large number of female birds , such as fowls , various pheasants , partridges , peahens , ducks , & c . , when old or diseased , or when ...
Pagina 64
... exist at first in nearly equal numbers , the whole will sooner or later become intimately blended , but not so soon , both breeds being equally favoured in all respects , as might have been expected . The following calculation shows ...
... exist at first in nearly equal numbers , the whole will sooner or later become intimately blended , but not so soon , both breeds being equally favoured in all respects , as might have been expected . The following calculation shows ...
Pagina 68
... exist , effectually preventing self - fertilisation . There are , however , many hermaphrodite plants which are not in any way specially constructed to favour intercrossing , but which nevertheless commingle almost as freely as animals ...
... exist , effectually preventing self - fertilisation . There are , however , many hermaphrodite plants which are not in any way specially constructed to favour intercrossing , but which nevertheless commingle almost as freely as animals ...
Pagina 69
... exist , however , some plants which under their natural conditions appear to be always self - fertilised , such as the Bee Ophrys ( Ophrys apifera ) and a few other Orchids ; yet these plants exhibit the plainest adaptations for cross ...
... exist , however , some plants which under their natural conditions appear to be always self - fertilised , such as the Bee Ophrys ( Ophrys apifera ) and a few other Orchids ; yet these plants exhibit the plainest adaptations for cross ...
Alte ediții - Afișează-le pe toate
The Variation of Animals and Plants Under Domestication V2 Professor Charles Darwin Nu există previzualizare disponibilă - 2014 |
The Variation of Animals and Plants Under Domestication V2 Charles Darwin Nu există previzualizare disponibilă - 2014 |
Termeni și expresii frecvente
analogous animals and plants Antirrhinum appear beak become birds bred breeders breeds buds cattle cause cells changed conditions chapter characters climate close interbreeding colour common correlation crossed degree diseases distinct species dogs domestic races domesticated animals doubt effects extremely facts Fancy Pigeons feathers female fertilised fertility flowers fowls Fritz Müller fruit Gard Gardener's Chronicle Gärtner gemmules given Hist horses hybrids improved individuals inherited insects instance Isidore Geoffroy Saint-Hilaire Journal kind Kölreuter large number larvæ liable maize male manner modified natural selection natural species nectarine niata observed occasionally offspring Oncidium flexuosum organs ovules pangenesis Paraguay parent parent-forms Parthenogenesis peculiar peloric period petals pigeons pigs pollen pollen-grains prepotent probably produced progenitor propagated quadrupeds racter remarks reproductive respect result reversion seed seedlings seen sexual sheep slight stamens sterility stripes structure tendency tion transmitted variability variations varieties various vary whilst wild yield Youatt
Pasaje populare
Pagina 488 - XVIII. The Nature of Light. With a General Account of Physical Optics. By Dr. Eugene Lommel. With 188 Illustrations and a Table of Spectra in Chromo-lithography.
Pagina 481 - ... publishers will spare no pains to include in the series the freshest investigations of the best scientific minds."— Boston Journal. " This series is admirably commenced by this little volume from the pen of Prof.
Pagina 481 - ... from giving a fuller account of these suggestive essays, only because we are sure that our readers will find it worth their while to peruse the book for themselves ; and we sincerely hope that the forthcoming parts of the 'International Scientific Series
Pagina 487 - ... science — the Chemistry of Light — and, in giving a popular view to the one, Dr. Vogel has presented an analysis of the principles and processes of the other. His treatise is as entertaining as it is instructive, pleasantly combining a history of the progress and practice of photography — from the first rough experiments of Wedgwood and Davy with sensitized paper, in 1802, down to the latest improvements of the art — with technical illustrations of the scientific theories on which the...
Pagina 412 - ... no shadow of reason can be assigned for the belief that variations, alike in nature and the result of the same general laws, which have been the ground-work through natural selection of the formation of the most perfectly adapted animals in the world, man included, were intentionally and specially guided. However much we may wish it, we can hardly follow Professor Asa Gray in his belief 'that variation has been led along certain beneficial lines, like a stream, along definite and useful lines...
Pagina 484 - ... but can be reduced to similar formula. The work is profusely illustrated, and, without reference to the theory it is designed to expound, will be regarded as a valuable addition to natural history.
Pagina 23 - As a general rule, crossed offspring in the first generation are nearly intermediate between their parents, but the grandchildren and succeeding generations continually revert, in a greater or lesser degree, to one or both of their progenitors.
Pagina 75 - Unless the characteristics and conformation of the two breeds are altogether averse to each other, nature opposes no barrier to their successful admixture ; so that, in the course of time, by the aid of selection and careful weeding, it is practicable to establish a new breed altogether.
Pagina 481 - The ' Forms of Water,' by Professor Tyndall, is an interesting and instructive little volume, admirably printed and illustrated. Prepared expressly for this series, it is in some measure a guarantee of the excellence of the volumes that will follow, and an indication that the publishers will spare no pains to include in the series the freshest investigations of the best scientific minds."—Boston Journal.
Pagina 483 - For, to those advanced students who have kept well abreast of the chemical tide, it offers a calm philosophy. To those others, youngest of the class, who have emerged from the schools since new methods have prevailed, it presents a generalization, drawing to its use all the data, the relations of which...