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
... colour and various black marks in all the breeds , both when kept pure and when crossed ; -and lastly , the mongrel off- spring being perfectly fertile ; -from these several reasons , taken together , we may safely conclude that all our ...
... colour and various black marks in all the breeds , both when kept pure and when crossed ; -and lastly , the mongrel off- spring being perfectly fertile ; -from these several reasons , taken together , we may safely conclude that all our ...
Página 23
... colour , shape , and hairiness , and yet the flowers present very slight differences . It is not that the varieties which differ largely in some one point do not differ at all in other points ; this is hardly ever , -I speak after ...
... colour , shape , and hairiness , and yet the flowers present very slight differences . It is not that the varieties which differ largely in some one point do not differ at all in other points ; this is hardly ever , -I speak after ...
Página 27
... colour , that most fleeting of characters , have lately been exhibited as distinct at our poultry - shows . These views appear to explain what has sometimes been noticed -namely , that we know hardly anything about the origin or history ...
... colour , that most fleeting of characters , have lately been exhibited as distinct at our poultry - shows . These views appear to explain what has sometimes been noticed -namely , that we know hardly anything about the origin or history ...
Página 29
... colour and probably with the length of hair . With respect to fleetness , which depends on many bodily characters , Eclipse was far fleeter , and a dray - horse is in- comparably stronger than any two natural species belonging to the ...
... colour and probably with the length of hair . With respect to fleetness , which depends on many bodily characters , Eclipse was far fleeter , and a dray - horse is in- comparably stronger than any two natural species belonging to the ...
Página 36
... colour , size , or in the nature of their secretions . In some instances the 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 ...
... colour , size , or in the nature of their secretions . In some instances the 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 ...
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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