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 37
... intermediate states . After this discussion , the result of so much labour , he emphatically remarks : " They are mistaken , who repeat that the greater part of our species are clearly limited , and that the doubtful species are in a ...
... intermediate states . After this discussion , the result of so much labour , he emphatically remarks : " They are mistaken , who repeat that the greater part of our species are clearly limited , and that the doubtful species are in a ...
Página 38
... intermediate links , he will be com- pelled to trust almost entirely to analogy , and his difficulties will rise to a climax . Certainly no clear line of demarcation has as yet been drawn between species and sub - species - that is ...
... intermediate links , he will be com- pelled to trust almost entirely to analogy , and his difficulties will rise to a climax . Certainly no clear line of demarcation has as yet been drawn between species and sub - species - that is ...
Página 42
... intermediate links have not been found between doubtful forms , naturalists are compelled to come to a determination by the amount of difference between them , judging by analogy whether or not the amount suffices to raise one or both ...
... intermediate links have not been found between doubtful forms , naturalists are compelled to come to a determination by the amount of difference between them , judging by analogy whether or not the amount suffices to raise one or both ...
Página 43
... intermediate linking forms ; and , secondly , by a certain indefinite amount of difference between them ; for two forms , if differing very little , are generally ranked as varieties , notwithstanding that they cannot be closely ...
... intermediate linking forms ; and , secondly , by a certain indefinite amount of difference between them ; for two forms , if differing very little , are generally ranked as varieties , notwithstanding that they cannot be closely ...
Página 75
... intermediate varieties , inhabiting intermediate districts , will in the long run generally be supplanted by one of the adjoining varieties . Intercrossing will chiefly affect those animals which unite for each birth and wander much ...
... intermediate varieties , inhabiting intermediate districts , will in the long run generally be supplanted by one of the adjoining varieties . Intercrossing will chiefly affect those animals which unite for each birth and wander much ...
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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