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 151
... organs might readily be modified and perfected so as to perform all the work , being aided during the progress of modification by the other organ ; and then this other organ might be modified for some other and quite distinct purpose ...
... organs might readily be modified and perfected so as to perform all the work , being aided during the progress of modification by the other organ ; and then this other organ might be modified for some other and quite distinct purpose ...
Página 154
... organs , and as we know nothing about the habits and structure of the progenitors of the existing electric fishes , it would be extremely bold to maintain that no serviceable transitions are possible by which these organs might have ...
... organs , and as we know nothing about the habits and structure of the progenitors of the existing electric fishes , it would be extremely bold to maintain that no serviceable transitions are possible by which these organs might have ...
Página 412
... organ or lung . Many similar instances could be given . Useful organs , however little they may be developed , unless we have reason to suppose that they were formerly more highly developed , ought not to be considered as rudimentary ...
... organ or lung . Many similar instances could be given . Useful organs , however little they may be developed , unless we have reason to suppose that they were formerly more highly developed , ought not to be considered as rudimentary ...
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