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 7
... vary very slightly- perhaps hardly more than in a state of nature . Some naturalists have maintained that all variations are con- nected with the act of sexual reproduction ; but this is certainly an error ; for I have given in another ...
... vary very slightly- perhaps hardly more than in a state of nature . Some naturalists have maintained that all variations are con- nected with the act of sexual reproduction ; but this is certainly an error ; for I have given in another ...
Página 12
... vary , and likewise to withstand diverse climates . I do not dispute that these capacities have added largely to the value of most of our domesticated productions ; but how could a savage possibly know , when he first tamed an animal ...
... vary , and likewise to withstand diverse climates . I do not dispute that these capacities have added largely to the value of most of our domesticated productions ; but how could a savage possibly know , when he first tamed an animal ...
Página 15
... varies in a highly remarkable manner . The caudal and sacral vertebræ vary in number ; as does the number of the ribs , together with their relative breadth and the presence of processes . The size and shape of the apertures in the ...
... varies in a highly remarkable manner . The caudal and sacral vertebræ vary in number ; as does the number of the ribs , together with their relative breadth and the presence of processes . The size and shape of the apertures in the ...
Página 16
... varies , as does the state of the down with which the nestling birds are clothed when hatched . The shape and size of the eggs vary . The manner of flight , and in some breeds the voice and disposition , differs remarkably . Lastly , in ...
... varies , as does the state of the down with which the nestling birds are clothed when hatched . The shape and size of the eggs vary . The manner of flight , and in some breeds the voice and disposition , differs remarkably . Lastly , in ...
Página 20
... varies slightly , for they win their prizes by selecting such slight differences , yet they ignore all general arguments , and refuse to sum up in their minds slight differences accumulated during many successive generations . May not ...
... varies slightly , for they win their prizes by selecting such slight differences , yet they ignore all general arguments , and refuse to sum up in their minds slight differences accumulated during many successive generations . May not ...
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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