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 331
... region ; and it has been observed by several naturalists that the most natural genera , or those genera in which the ... regions ; and secondly ( in the following chapter ) , the wide distribution of freshwater productions ; and thirdly ...
... region ; and it has been observed by several naturalists that the most natural genera , or those genera in which the ... regions ; and secondly ( in the following chapter ) , the wide distribution of freshwater productions ; and thirdly ...
Página 345
... region with the native American productions , and would have had to compete with them ; and in the other great region ... regions of the New and Old Worlds , we find very few identical species ( though Asa Gray has lately shown that more ...
... region with the native American productions , and would have had to compete with them ; and in the other great region ... regions of the New and Old Worlds , we find very few identical species ( though Asa Gray has lately shown that more ...
Página 373
... regions , and which , during the alternations of the cold in the north and south , allowed the productions of opposite hemispheres to mingle , and left some of them stranded on the mountain - summits in all parts of the world . As ...
... regions , and which , during the alternations of the cold in the north and south , allowed the productions of opposite hemispheres to mingle , and left some of them stranded on the mountain - summits in all parts of the world . As ...
Contenido
VARIATION UNDER NATURE | 30 |
STRUGGLE FOR EXISTENCE | 45 |
NATURAL SELECTION | 59 |
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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