On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeEaston Press, 1976 - 470 páginas |
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Página 14
... supposed aboriginal stocks must all have been rock - pigeons , that is , they did not breed or willingly perch on trees . But besides C. livia , with its geographical sub - species , only two or three other species of rock - pigeons are ...
... supposed aboriginal stocks must all have been rock - pigeons , that is , they did not breed or willingly perch on trees . But besides C. livia , with its geographical sub - species , only two or three other species of rock - pigeons are ...
Página 89
... supposed to resemble each other in organic beings unequal degrees , as is so generally the case in nature , and as ... supposed to be extremely slight , but of the most diversified nature ; they are not supposed all to appear ...
... supposed to resemble each other in organic beings unequal degrees , as is so generally the case in nature , and as ... supposed to be extremely slight , but of the most diversified nature ; they are not supposed all to appear ...
Página 95
... supposed progenitor of our several new sub - genera and genera . It is worth while to reflect for a moment on the character of the new species F14 , which is supposed not to have diverged much in character , but to have retained the ...
... supposed progenitor of our several new sub - genera and genera . It is worth while to reflect for a moment on the character of the new species F14 , which is supposed not to have diverged much in character , but to have retained the ...
Contenido
VARIATION UNDER NATURE | 30 |
STRUGGLE FOR EXISTENCE | 45 |
NATURAL SELECTION | 59 |
Derechos de autor | |
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Términos y frases comunes
accumulated adapted admit affinities allied species America ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common progenitor continuous crossed crustaceans degree developed difficulty distinct species divergence doubt effects eggs embryo existing exterminated extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period gradations greater number groups of species habits Hence hybrids hybrids produced 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 offspring organisation organs Origin of Species parent peculiar perfect pigeons pistil plants pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds slight South America stamens sterility structure struggle successive supposed swimbladder theory variability variations varieties vary whilst whole wings young