The Origin of Species by Means of Natural Selection: Or the Preservation of Favored Races in the Struggle for LifeD. Appleton, 1904 - 435 páginas |
Dentro del libro
Resultados 1-5 de 69
Página xvi
... colour of this vigorous race I take for granted , from what has been already said , would be dark . But the same disposition to form varieties still existing , a darker and a darker race would in the course of time occur : and as the ...
... colour of this vigorous race I take for granted , from what has been already said , would be dark . But the same disposition to form varieties still existing , a darker and a darker race would in the course of time occur : and as the ...
Página 9
... colour from the nature of the food , thickness of the skin and hair from climate , & c . Each of the endless variations which we see in the plumage of our fowls must have had some efficient cause ; and if the same cause were to act ...
... colour from the nature of the food , thickness of the skin and hair from climate , & c . Each of the endless variations which we see in the plumage of our fowls must have had some efficient cause ; and if the same cause were to act ...
Página 13
... Colour and con- stitutional peculiarities go together , of which many re- markable cases could be given amongst ... coloured individuals escape : Professor Wy- man has recently communicated to me a good illustra- tion of this fact ; on ...
... Colour and con- stitutional peculiarities go together , of which many re- markable cases could be given amongst ... coloured individuals escape : Professor Wy- man has recently communicated to me a good illustra- tion of this fact ; on ...
Página 29
... colour , with the white loins , double black wing - bar , and barred and white - edged tail- feathers , as any wild ... coloured and marked like the rock - pigeon , although no other existing species is thus coloured and marked , so that ...
... colour , with the white loins , double black wing - bar , and barred and white - edged tail- feathers , as any wild ... coloured and marked like the rock - pigeon , although no other existing species is thus coloured and marked , so that ...
Página 30
... - appearance of the blue colour and various black marks in all the breeds , both when kept pure and when crossed ; -and lastly , the mongrel offspring being perfectly fertile ; -from these several reasons 30 [ CHAP . I. DOMESTIC PIGEONS .
... - appearance of the blue colour and various black marks in all the breeds , both when kept pure and when crossed ; -and lastly , the mongrel offspring being perfectly fertile ; -from these several reasons 30 [ CHAP . I. DOMESTIC PIGEONS .
Otras ediciones - Ver todas
Términos y frases comunes
adapted affinities allied species America ancient appear Asa Gray 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 effects eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period 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 males mammals manner marsupials migration modified descendants natural selection naturalists nearly nest occasionally offspring organisation organs parent peculiar perfect pigeon pistil pollen present principle probably produced progenitor quadrupeds ranked remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed swimbladder tend theory tion trees variability variations varieties vary whilst whole wings young