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 12
... kind truly , were the offspring of any 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 ...
... kind truly , were the offspring of any 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 ...
Página 22
... kind of selection is , in fact , likewise followed ; for hardly any one is so careless as to breed from his worst animals . In regard to plants , there is another means of observing the accumulated effects of selection - namely , by ...
... kind of selection is , in fact , likewise followed ; for hardly any one is so careless as to breed from his worst animals . In regard to plants , there is another means of observing the accumulated effects of selection - namely , by ...
Página 23
... At the present time , eminent breeders try by methodical selec- tion , with a distinct object in view , to make a new strain or sub- breed , superior to anything of the kind in the. CHAP . I. ] 23 UNCONSCIOUS SELECTION .
... At the present time , eminent breeders try by methodical selec- tion , with a distinct object in view , to make a new strain or sub- breed , superior to anything of the kind in the. CHAP . I. ] 23 UNCONSCIOUS SELECTION .
Página 24
... kind in the country . But , for our purpose , a form of Selection , which may be called Unconscious , and which results from every one trying to possess and breed from the best individual animals , is more important . Thus , a man who ...
... kind in the country . But , for our purpose , a form of Selection , which may be called Unconscious , and which results from every one trying to possess and breed from the best individual animals , is more important . Thus , a man who ...
Página 25
... kind of unconscious selection going on . We see the value set on animals even by the barbarians of Tierra del Fuego , by their killing and devouring their old women , in times of dearth , as of less value than their dogs . In plants the ...
... kind of unconscious selection going on . We see the value set on animals even by the barbarians of Tierra del Fuego , by their killing and devouring their old women , in times of dearth , as of less value than their dogs . In plants the ...
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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