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 8
... single bud out of the many thousands , produced year after year on the same tree under uniform conditions , has been known suddenly to assume a new character ; and as buds on distinct trees , growing under different conditions , have ...
... single bud out of the many thousands , produced year after year on the same tree under uniform conditions , has been known suddenly to assume a new character ; and as buds on distinct trees , growing under different conditions , have ...
Página 10
... single variety should have been turned loose in its new home . Nevertheless , as our varieties certainly do occasionally revert in some of their characters to ancestral forms , it seems. 10 VARIATION UNDER DOMESTICATION . [ CHAP . I.
... single variety should have been turned loose in its new home . Nevertheless , as our varieties certainly do occasionally revert in some of their characters to ancestral forms , it seems. 10 VARIATION UNDER DOMESTICATION . [ CHAP . I.
Página 12
... single species , then such facts would have great weight in making us doubt about the immuta- bility of the many closely allied natural species - for instance , of the many foxes - inhabiting different quarters of the world . I do not ...
... single species , then such facts would have great weight in making us doubt about the immuta- bility of the many closely allied natural species - for instance , of the many foxes - inhabiting different quarters of the world . I do not ...
Página 21
... single lifetime , modified to a large extent their breeds of cattle and sheep . In order fully to realise what they have done , it is almost necessary to read several of the many treatises devoted to this subject , and to inspect the ...
... single lifetime , modified to a large extent their breeds of cattle and sheep . In order fully to realise what they have done , it is almost necessary to read several of the many treatises devoted to this subject , and to inspect the ...
Página 22
... single variation from the aboriginal stock . We have proofs that this has not been so in several cases in which exact records have been kept ; thus , to give a very trifling instance , the steadily - increasing size of the common ...
... single variation from the aboriginal stock . We have proofs that this has not been so in several cases in which exact records have been kept ; thus , to give a very trifling instance , the steadily - increasing size of the common ...
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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