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 372
... respect to the many curious means of occasional transport , if we bear in mind , and this is a very important consideration , how often a species may have ranged continuously over a wide area , and then have become extinct in the ...
... respect to the many curious means of occasional transport , if we bear in mind , and this is a very important consideration , how often a species may have ranged continuously over a wide area , and then have become extinct in the ...
Página 408
... respect to the final cause of the young in such groups not passing through any metamorphosis , we can see that this would follow from the following contingencies ; namely , from the young having to provide at a very early age for their ...
... respect to the final cause of the young in such groups not passing through any metamorphosis , we can see that this would follow from the following contingencies ; namely , from the young having to provide at a very early age for their ...
Página 422
... respect to distinct species of the same genus inhabiting distant and isolated regions , as the process of modification has necessarily been slow , all the means of migration will have been possible during a very long period ; and ...
... respect to distinct species of the same genus inhabiting distant and isolated regions , as the process of modification has necessarily been slow , all the means of migration will have been possible during a very long period ; and ...
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