The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432 páginas |
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Página vii
... various in degree , not universal , affected by close interbreeding , removed by domestication - Laws governing the sterility of hybrids - Sterility not a special endowment , but incidental on other differences , not accumulated by ...
... various in degree , not universal , affected by close interbreeding , removed by domestication - Laws governing the sterility of hybrids - Sterility not a special endowment , but incidental on other differences , not accumulated by ...
Página xiv
... various degenerations of the same type . It was not until 1828 that he published his conviction that the same forms have not been per- petuated since the origin of all things . Geoffroy seems to have relied chiefly on the conditions of ...
... various degenerations of the same type . It was not until 1828 that he published his conviction that the same forms have not been per- petuated since the origin of all things . Geoffroy seems to have relied chiefly on the conditions of ...
Página 6
... various organs . With respect to what I have called the indirect action of changed conditions , namely , through the reproductive system of being affected , we may infer that variability is thus induced , partly from the fact of this ...
... various organs . With respect to what I have called the indirect action of changed conditions , namely , through the reproductive system of being affected , we may infer that variability is thus induced , partly from the fact of this ...
Página 9
... various , unknown , or but dimly understood laws of variation are infinitely complex and diversified . It is well worth while carefully to study the several treatises on some of our old cultivated plants , as on the hyacinth , potato ...
... various , unknown , or but dimly understood laws of variation are infinitely complex and diversified . It is well worth while carefully to study the several treatises on some of our old cultivated plants , as on the hyacinth , potato ...
Página 19
... various black marks in all the breeds , both when kept pure and when crossed ; -and lastly , the mongrel off- spring being perfectly fertile ; -from these several reasons , taken together , we may safely conclude that all our domestic ...
... various black marks in all the breeds , both when kept pure and when crossed ; -and lastly , the mongrel off- spring being perfectly fertile ; -from these several reasons , taken together , we may safely conclude that all our domestic ...
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Términos y frases comunes
accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number 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 occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion variability variations varieties vary whilst whole wings young