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 25
... plants , when compared with the older varieties or with their parent - stocks . No one would ever expect to get a first - rate hearts- ease or dahlia from the seed of a wild plant . No one would expect to raise a first - rate melting ...
... plants , when compared with the older varieties or with their parent - stocks . No one would ever expect to get a first - rate hearts- ease or dahlia from the seed of a wild plant . No one would expect to raise a first - rate melting ...
Página 26
... plants , but that the native plants have not been improved by continued selection up to a standard of perfection comparable with that acquired by the plants in countries anciently civilised . In regard to the domestic animals kept by ...
... plants , but that the native plants have not been improved by continued selection up to a standard of perfection comparable with that acquired by the plants in countries anciently civilised . In regard to the domestic animals kept by ...
Página 28
... plant . No doubt the strawberry had always varied since it was cultivated , but the slight varieties had been neglected . As soon , however , as gardeners picked out individual plants with slightly larger , earlier , or better fruit ...
... plant . No doubt the strawberry had always varied since it was cultivated , but the slight varieties had been neglected . As soon , however , as gardeners picked out individual plants with slightly larger , earlier , or better fruit ...
Página 29
... plants have been greatly improved in many ways within a recent period ; and this implies variation . It would be equally rash to assert that characters now increased to their usual limit , could not , after remaining fixed for many ...
... plants have been greatly improved in many ways within a recent period ; and this implies variation . It would be equally rash to assert that characters now increased to their usual limit , could not , after remaining fixed for many ...
Página 30
... plants which are propagated by seed . With plants which are temporarily propa- gated by cuttings , buds , & c . , the importance of crossing is im- mense ; for the cultivator may here disregard the extreme variability both of hybrids ...
... plants which are propagated by seed . With plants which are temporarily propa- gated by cuttings , buds , & c . , the importance of crossing is im- mense ; for the cultivator may here disregard the extreme variability both of hybrids ...
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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