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 6
... domestic races . We see indefinite variability in the endless slight peculiarities which distinguish the individuals of the same species , and which cannot be accounted for by inheritance from either parent or from some more remote ...
... domestic races . We see indefinite variability in the endless slight peculiarities which distinguish the individuals of the same species , and which cannot be accounted for by inheritance from either parent or from some more remote ...
Página 8
... domestic duck that the bones of the wing weigh less and the bones of the leg more , in proportion to the whole skeleton , than do the same bones in the wild duck ; and this change may be safely attributed to the domestic duck flying ...
... domestic duck that the bones of the wing weigh less and the bones of the leg more , in proportion to the whole skeleton , than do the same bones in the wild duck ; and this change may be safely attributed to the domestic duck flying ...
Página 10
... domestic varieties , when run wild , gradually but invariably revert in cha- racter to their aboriginal stocks . Hence it has been argued that no deductions can be drawn from domestic races to species in a state of nature . I have in ...
... domestic varieties , when run wild , gradually but invariably revert in cha- racter to their aboriginal stocks . Hence it has been argued that no deductions can be drawn from domestic races to species in a state of nature . I have in ...
Página 11
... domestic varieties manifested a strong tendency to reversion , -that is , to lose their acquired characters , whilst kept under the same conditions , and whilst kept in a considerable body , so that free intercrossing might check , by ...
... domestic varieties manifested a strong tendency to reversion , -that is , to lose their acquired characters , whilst kept under the same conditions , and whilst kept in a considerable body , so that free intercrossing might check , by ...
Página 12
... domestic races , we are soon involved in doubt , from not knowing whether they are descended from one or several parent species . This point , if it could be cleared up , would be interesting ; if , for instance , it could be shown that ...
... domestic races , we are soon involved in doubt , from not knowing whether they are descended from one or several parent species . This point , if it could be cleared up , would be interesting ; if , for instance , it could be shown that ...
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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