The Variation of Animals and Plants Under Domestication, Volume 2D. Appleton, 1892 |
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analogous animals and plants Antirrhinum appear become birds bred breeders breeds buds capsules cattle cause cells changed conditions chapter characters climate close interbreeding colour 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 havo Hist horns horses hybrids individuals inherited insects instance Isidore Geoffroy Saint-Hilaire Journal kind large number larvæ liable maize male manner modified natural selection natural species nectarines 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 racter remarks reproductive respect result reversion seed seedlings seen sheep slight stamens sterility stripes structure tendency tion transmitted variability variations varieties various vary whilst wild yield Youatt Zoological Gardens
Popular passages
Page 244 - of all the causes which induce variability, excess of food, whether or not changed in nature, is probably the most powerful.
Page 370 - They are collected from all parts of the system to constitute the sexual elements, and their development in the next generation forms a new being ; but they are likewise capable of transmission in a dormant state to future generations and may then be developed.
Page 428 - ... alike in nature and the result of the same general laws, which have been the groundwork 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 of irrigation.
Page 367 - The domesticated duck flies less and walks more than the wild duck, and its limb-bones have become diminished and increased in a corresponding manner in comparison with those of the wild duck. A horse is trained to certain paces, and the colt inherits similar consensual movements.
Page 426 - ... rendered in some degree plastic, and that each slight modification of structure which was in any way beneficial under excessively complex conditions of life has been preserved, whilst each which was in any way injurious has been rigorously destroyed. And the long-continued accumulation of beneficial variations will infallibly have led...
Page 495 - A work by a master in the science who understands the significance of every phenomenon which he records, and knows how to make it reveal its lessons. As regards its value there can scarcely exist two opinions. As a text-book of the historical phase of...
Page 250 - Vilmorin,'8 even maintains that, when any particular variation is desired, the first step is to get the plant to vary in any manner whatever, and to go on selecting the most variable individuals, even though they vary in the wrong direction; for the fixed character of the species being once broken, the desired variation will sooner or later appear.
Page 242 - These several considerations alone render it probable that variability of every kind is directly or indirectly caused by changed conditions of life. Or, to put the case under another point of view, if it were possible to expose all the individuals of a species during many generations to absolutely uniform conditions of life, there •would be no variability.