On the Origin of Species by Means of Natural Selection: Or The Preservation of Favored Races in the Struggle for Life, Volumen2D. Appleton, 1888 - 458 páginas |
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Página xiii
... hand , have believed that species undergo modification , and that the existing forms of life are the descendants by true generation of pre - existing forms . Passing over allusions to the subject in the classical writers , * the first ...
... hand , have believed that species undergo modification , and that the existing forms of life are the descendants by true generation of pre - existing forms . Passing over allusions to the subject in the classical writers , * the first ...
Página xxi
... hand , we view Persistent Types ' in relation to that hypothesis which supposes the species living at any time to be the result of the gradual modification of pre - existing species - a hypothesis which , though unproven , and sadly ...
... hand , we view Persistent Types ' in relation to that hypothesis which supposes the species living at any time to be the result of the gradual modification of pre - existing species - a hypothesis which , though unproven , and sadly ...
Página 6
... hand , dissimila variations arise under conditions which appear to be nearly uniform . The effects on the offspring are either definite or indefinite . They may be considered as definite when all or nearly all the offspring of ...
... hand , dissimila variations arise under conditions which appear to be nearly uniform . The effects on the offspring are either definite or indefinite . They may be considered as definite when all or nearly all the offspring of ...
Página 7
... hand , we see domesticated animals and plants , though often weak and sickly , breeding freely under confinement ; and when , on the other hand , we see individuals , though taken young from a state of nature perfectly tamed , long ...
... hand , we see domesticated animals and plants , though often weak and sickly , breeding freely under confinement ; and when , on the other hand , we see individuals , though taken young from a state of nature perfectly tamed , long ...
Página 29
... hand , nurserymen , from keeping large stocks of the same plant , are gener- ally far more successful than amateurs in raising new and valuable varieties . A large number of individuals of an animal or plant can 66 be reared only where ...
... hand , nurserymen , from keeping large stocks of the same plant , are gener- ally far more successful than amateurs in raising new and valuable varieties . A large number of individuals of an animal or plant can 66 be reared only where ...
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Términos y frases comunes
adapted admit affinities allied species America analogous ancient appear Asa Gray beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species doubt effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important 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 reproductive resemblance rudimentary seeds sexual selection slight South America stamens sterility structure struggle successive supposed tend theory tion variability variations varieties vary whilst whole wings young