The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432 páginas |
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Página 19
... male and female pigeons can be easily mated for life ; and thus different breeds can be kept together in the same aviary . I have discussed the probable origin of domestic pigeons at. CHAP . I. ] 19 DOMESTIC PIGEONS .
... male and female pigeons can be easily mated for life ; and thus different breeds can be kept together in the same aviary . I have discussed the probable origin of domestic pigeons at. CHAP . I. ] 19 DOMESTIC PIGEONS .
Página 33
... males of certain Brazilian Crustaceans : thus , the male of a Tanais regularly occurs under two distinct forms ; one of these has strong and differently shaped pincers , and the other has antennæ much more abundantly furnished with ...
... males of certain Brazilian Crustaceans : thus , the male of a Tanais regularly occurs under two distinct forms ; one of these has strong and differently shaped pincers , and the other has antennæ much more abundantly furnished with ...
Página 36
... males alone , in other instances both males and females , have been observed thus to differ in a slight degree . When the differences are rather more strongly marked , and when both sexes and all ages are affected , the forms are ranked ...
... males alone , in other instances both males and females , have been observed thus to differ in a slight degree . When the differences are rather more strongly marked , and when both sexes and all ages are affected , the forms are ranked ...
Página 60
... males to struggle for the females . He does not rigidly destroy all inferior animals , but protects during each varying season , as far as lies in his power , all his productions . He often begins his selection by some half - monstrous ...
... males to struggle for the females . He does not rigidly destroy all inferior animals , but protects during each varying season , as far as lies in his power , all his productions . He often begins his selection by some half - monstrous ...
Página 64
... male alligators have been described as fighting , bellowing , and whirling round , like Indians in a war - dance , for the possession of the females ; male salmons have been observed fighting all day long ; male stag - beetles some ...
... male alligators have been described as fighting , bellowing , and whirling round , like Indians in a war - dance , for the possession of the females ; male salmons have been observed fighting all day long ; male stag - beetles some ...
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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 continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids 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 occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced 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