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 412
... organ , serving for two purposes , may become rudimentary or utterly aborted for one , even the more important purpose , and remain perfectly efficient for the other . Thus in plants , the office of the pistil is to allow the pollen ...
... organ , serving for two purposes , may become rudimentary or utterly aborted for one , even the more important purpose , and remain perfectly efficient for the other . Thus in plants , the office of the pistil is to allow the pollen ...
Página 413
... Rudimentary organs in the individuals of the same species are very liable to vary in the degree of their development and in other respects . In closely allied species , also , the extent to which the same organ has been reduced ...
... Rudimentary organs in the individuals of the same species are very liable to vary in the degree of their development and in other respects . In closely allied species , also , the extent to which the same organ has been reduced ...
Página 414
... rudimentary or atrophied organs are imperfect and useless . In works on natural history , rudimentary organs are generally said to have been created " for the sake of symmetry , " or in order " to complete the scheme of nature . " But ...
... rudimentary or atrophied organs are imperfect and useless . In works on natural history , rudimentary organs are generally said to have been created " for the sake of symmetry , " or in order " to complete the scheme of nature . " But ...
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