The Origin of Species by Means of Natural Selection: Or the Preservation of Favored Races in the Struggle for LifeD. Appleton, 1904 - 435 páginas |
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Página 6
... less do we know of the mutual rela- tions of the innumerable inhabitants of the world during the many past geological epochs in its history . Although much remains obscure , and will long remain obscure , I can entertain no doubt ...
... less do we know of the mutual rela- tions of the innumerable inhabitants of the world during the many past geological epochs in its history . Although much remains obscure , and will long remain obscure , I can entertain no doubt ...
Página 10
... less water at some particular period of growth , will determine whether or not a plant will produce seeds . I cannot here give the details which I have collected and elsewhere published on this curious subject ; but to show how singular ...
... less water at some particular period of growth , will determine whether or not a plant will produce seeds . I cannot here give the details which I have collected and elsewhere published on this curious subject ; but to show how singular ...
Página 12
... 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 much less , and walking more , than its wild ...
... 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 much less , and walking more , than its wild ...
Página 18
... less uniformity of character than in true species . Domestic races often have a somewhat monstrous character ; by which I mean , that , although differing from each other , and from other species of the same genus , in several trifling ...
... less uniformity of character than in true species . Domestic races often have a somewhat monstrous character ; by which I mean , that , although differing from each other , and from other species of the same genus , in several trifling ...
Página 29
... less and less , as in each suc ceeding generation there will be less of the foreign blood ; but when there has been no cross , and there is a tendency in the breed to revert to a CHAP . I. ] 29 DOMESTIC PIGEONS .
... less and less , as in each suc ceeding generation there will be less of the foreign blood ; but when there has been no cross , and there is a tendency in the breed to revert to a CHAP . I. ] 29 DOMESTIC PIGEONS .
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Términos y frases comunes
adapted affinities allied species America ancient appear Asa Gray beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common continent crossed crustaceans degree developed difficulty distinct species domestic doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hybrids important individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living males mammals manner marsupials migration modified descendants natural selection naturalists nearly nest occasionally offspring organisation organs parent peculiar perfect pigeon pistil pollen present principle probably produced progenitor quadrupeds ranked remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed swimbladder tend theory tion trees variability variations varieties vary whilst whole wings young