On 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 8
... widely distinct in the scale of nature can be crossed more easily than in the case of plants ; but the hybrids themselves are , I think , more sterile . It should , however , be borne in mind that , owing to few animals breeding freely ...
... widely distinct in the scale of nature can be crossed more easily than in the case of plants ; but the hybrids themselves are , I think , more sterile . It should , however , be borne in mind that , owing to few animals breeding freely ...
Página 14
... widely different in habit and general appearance , and having strongly marked differ- ences in every part of the flower , even in the pollen , in the fruit , and in the cotyledons , can be crossed . An- nual and perennial plants ...
... widely different in habit and general appearance , and having strongly marked differ- ences in every part of the flower , even in the pollen , in the fruit , and in the cotyledons , can be crossed . An- nual and perennial plants ...
Página 18
... widely different climates , do not always prevent the two grafting together . As in hybridisation , so with grafting , the capacity is limited by systematic affinity , for no one has been able to graft together trees belonging to quite ...
... widely different climates , do not always prevent the two grafting together . As in hybridisation , so with grafting , the capacity is limited by systematic affinity , for no one has been able to graft together trees belonging to quite ...
Página 28
... widely or specifically different , produce hybrids which are almost always in some degree sterile . I am fully persuaded that this double parallelism is by no means an accident or an illusion . He who is able to explain why the elephant ...
... widely or specifically different , produce hybrids which are almost always in some degree sterile . I am fully persuaded that this double parallelism is by no means an accident or an illusion . He who is able to explain why the elephant ...
Página 35
... widely from each other in appearance , for instance those of the pigeon , or of the cabbage , is a remarkable fact ; more es- pecially when we reflect how many species there are , which , though resembling each other most closely , are ...
... widely from each other in appearance , for instance those of the pigeon , or of the cabbage , is a remarkable fact ; more es- pecially when we reflect how many species there are , which , though resembling each other most closely , are ...
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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