The Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeCollier Books, 1962 - 512 páginas |
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Página 210
... considered by De Candolle to be in other species of the highest systematic importance . Prof. Braun men- tions a Fumariaceous genus , in which the flowers in the lower part of the spike bear oval , ribbed , one - seeded nutlets ; and in ...
... considered by De Candolle to be in other species of the highest systematic importance . Prof. Braun men- tions a Fumariaceous genus , in which the flowers in the lower part of the spike bear oval , ribbed , one - seeded nutlets ; and in ...
Página 418
... considered of very trifling physiologi- cal importance , but which are universally admitted as highly serviceable in the definition of whole groups . For instance , whether or not there is an open passage from the nostrils to the mouth ...
... considered of very trifling physiologi- cal importance , but which are universally admitted as highly serviceable in the definition of whole groups . For instance , whether or not there is an open passage from the nostrils to the mouth ...
Página 424
... considered as vari- eties ; and now I have been able to show that they are the male , female , and hermaphrodite forms of the same species . The naturalist includes as one species the various larval stages of the same individual ...
... considered as vari- eties ; and now I have been able to show that they are the male , female , and hermaphrodite forms of the same species . The naturalist includes as one species the various larval stages of the same individual ...
Contenido
An Historical Sketch | 15 |
Introduction | 25 |
Variation Under Nature | 58 |
Derechos de autor | |
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Términos y frases comunes
accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common continent crossed crustaceans degree developed difficulty distinct species domestic doubt eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological Glacial period gradations greater number groups of species habits Hence hybrids important 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 pollen present principle probably produced progenitor quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion variability variations varieties vary whilst whole wings young