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 19
... points of structure with all the domestic breeds . Secondly , that , although an English carrier or a short - faced tumbler differs immensely in certain characters from the rock - pigeon , yet that , by comparing the several sub ...
... points of structure with all the domestic breeds . Secondly , that , although an English carrier or a short - faced tumbler differs immensely in certain characters from the rock - pigeon , yet that , by comparing the several sub ...
Página 23
... point do not differ at all in other points ; this is hardly ever , -I speak after careful observation , -perhaps never , the case . The law of correlated variation , the importance of which should never be overlooked , will ensure some ...
... point do not differ at all in other points ; this is hardly ever , -I speak after careful observation , -perhaps never , the case . The law of correlated variation , the importance of which should never be overlooked , will ensure some ...
Página 27
... points of the breed . Nor let it be thought that some great deviation of structure would be necessary to catch the fancier's eye : he perceives extremely small differences , and it is in human nature to fancy any novelty , however ...
... points of the breed . Nor let it be thought that some great deviation of structure would be necessary to catch the fancier's eye : he perceives extremely small differences , and it is in human nature to fancy any novelty , however ...
Página 32
... point of view , no instance will ever be found of an important part vary- ing ; but under any other point of view many instances assuredly can be given . There is one point connected with individual differences , which is extremely ...
... point of view , no instance will ever be found of an important part vary- ing ; but under any other point of view many instances assuredly can be given . There is one point connected with individual differences , which is extremely ...
Página 37
... points of structure which vary in the several species , and estimates numerically the relative frequency of the variations . He specifies above a dozen characters which may be found varying even on the same branch , sometimes according ...
... points of structure which vary in the several species , and estimates numerically the relative frequency of the variations . He specifies above a dozen characters which may be found varying even on the same branch , sometimes according ...
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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