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The Variation of Animals and Plants Under Domestication, Volumen2
Vista completa - 1868
The Variation of Animals and Plants Under Domestication, V2
Sin vista previa disponible - 2008
analogous animals and plants Antirrhinum appear become birds bred breeders breeds buds capsules cattle cause cells changed conditions chapter characters Chronicle climate close interbreeding colour common correlation crossed cultivated degree diseases distinct species dogs domestic races domesticated animals doubt effects extremely facts Fancy Pigeons feathers female fertilised fertility flowers fowls fruit Gardener's Gartner gemmules given havo Hist horses hybrids increased individuals inherited insects instance kind liable maize male manner modified natural selection natural species nectarine niata Notylia observed occasionally offspring organs ovules pangenesis Paraguay parent parent-forms parthenogenesis peculiar peloric period petals pigeons pigs pistil pollen pollen-grains prepotent probably produced progenitor propagated quadrupeds racter remarks reproductive respect result reversion samo seed seedlings seen sexual sheep slight stamens sterility stripes structure tendency tion torn transmitted variability variations varieties various vary wero whilst wild yield Zoological Gardens
Página 428 - ... 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...
Página 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.