The Variation of animals and plants under domestication v. 2, Volumul 2Appleton, 1876 |
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Pagina 11
... seed , of flowers reverting by stripes or blotches to their primitive colours : he states that in all such cases a white or pale - coloured variety must first be formed , and , when this is propagated for a length of time by seed ...
... seed , of flowers reverting by stripes or blotches to their primitive colours : he states that in all such cases a white or pale - coloured variety must first be formed , and , when this is propagated for a length of time by seed ...
Pagina 43
... seed - producing parents . " The law of prepotency comes into action when species are crossed , as with races and individuals . Gärtner has unequivocally shown 15 that this is the case with plants . To give one instance : when Nicotiana ...
... seed - producing parents . " The law of prepotency comes into action when species are crossed , as with races and individuals . Gärtner has unequivocally shown 15 that this is the case with plants . To give one instance : when Nicotiana ...
Pagina 52
... seeds of the several kinds of peas , beans , maize , which can be propagated truly , and see how they differ in size , colour ... seed , and the horn in a full - grown ox can resemble only a horn . The following cases show inheritance at ...
... seeds of the several kinds of peas , beans , maize , which can be propagated truly , and see how they differ in size , colour ... seed , and the horn in a full - grown ox can resemble only a horn . The following cases show inheritance at ...
Pagina 69
... seed . 17 Although some plants , both indigenous and naturalised , rarely or never produce flowers , or if they flower never produce seeds , yet no one doubts that phanerogamic plants are adapted to produce flowers , and the flowers to ...
... seed . 17 Although some plants , both indigenous and naturalised , rarely or never produce flowers , or if they flower never produce seeds , yet no one doubts that phanerogamic plants are adapted to produce flowers , and the flowers to ...
Pagina 76
... seed , most . of them freely ; but extremely few or none come true by seed . Some authors believe that crossing is the chief cause of variability , that is , of the appearance of absolutely new 33 Cottage Gardener , ' 1856 , p . 34 ...
... seed , most . of them freely ; but extremely few or none come true by seed . Some authors believe that crossing is the chief cause of variability , that is , of the appearance of absolutely new 33 Cottage Gardener , ' 1856 , p . 34 ...
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...