The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeAppleton, 1898 - 432 páginas |
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Página 2
... descended from common parents , when crossed , and likewise the fertility of their mongrel off- spring , is , with reference to my theory , of equal im- portance with the sterility of species ; for it seems to make a broad and clear ...
... descended from common parents , when crossed , and likewise the fertility of their mongrel off- spring , is , with reference to my theory , of equal im- portance with the sterility of species ; for it seems to make a broad and clear ...
Página 7
... descended from three distinct species : the result was that the ovaries of the three first flowers soon ceased to grow , and after a few days perished entirely , whereas the pod impregnated by the pollen of the hybrid made vigorous ...
... descended from three distinct species : the result was that the ovaries of the three first flowers soon ceased to grow , and after a few days perished entirely , whereas the pod impregnated by the pollen of the hybrid made vigorous ...
Página 10
... descended from two or more wild species . From this fact we must conclude either that the abo- riginal parent - species at first produced perfectly fertile hybrids , or that the hybrids subsequently reared under domestication became ...
... descended from two or more wild species . From this fact we must conclude either that the abo- riginal parent - species at first produced perfectly fertile hybrids , or that the hybrids subsequently reared under domestication became ...
Página 28
... descended from distinct species , which would probably have been sterile if aboriginally crossed . The above two parallel series of facts seem to be con- nected together by some common but unknown bond , which is essentially related to ...
... descended from distinct species , which would probably have been sterile if aboriginally crossed . The above two parallel series of facts seem to be con- nected together by some common but unknown bond , which is essentially related to ...
Página 34
... South American indigenous domes- tic dogs do not readily unite with European dogs , the explanation which will occur to every one , and probably the true one , is that they are descended from 34 [ CHAP . IX . FERTILITY OF VARIETIES.
... South American indigenous domes- tic dogs do not readily unite with European dogs , the explanation which will occur to every one , and probably the true one , is that they are descended from 34 [ CHAP . IX . FERTILITY OF VARIETIES.
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Términos y frases comunes
admit affinity allied species ancient animals appear Archipelago arctic areas become believe birds Cambrian changes characters cies classification climate closely allied common progenitor continent crustaceans degree deposited difficulty distant distinct species domestic doubt embryo eral Europe existing extinct fact faunas fertilised fertility flowers formations formerly forms fossil fresh-water Fritz Müller Gärtner genera genus geological period geological record Glacial period groups of species habits hybrids hybrids produced important individuals inhabitants inherited insects instance intermediate intervals land larvæ less living mammals manner marine Marsupials migration modified descendants mongrels mountains natural selection naturalists nearly occur oceanic islands offspring organisation parent parent-form peculiar perfect pistil plants pollen present probably produced quadrupeds reciprocal crosses regions remains remarked reproductive resemblance rocks rudimentary organs sediment seeds Silurian South America stage stamens sterility structure successive suppose terrestrial tertiary theory tion variations varieties whilst widely different wings