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 v
... sterility of first crosses and of hybrids- Sterility various in degree , not universal , affected by close in- terbreeding , removed by domestication - Laws governing the sterility of hybrids - Sterility not a special endowment , but ...
... sterility of first crosses and of hybrids- Sterility various in degree , not universal , affected by close in- terbreeding , removed by domestication - Laws governing the sterility of hybrids - Sterility not a special endowment , but ...
Página ix
... Sterility various in degree , not universal , affected by close in- terbreeding , removed by domestication - Laws governing the sterility of hybrids - Sterility not a special endowment , but incidental on other differences , not ...
... Sterility various in degree , not universal , affected by close in- terbreeding , removed by domestication - Laws governing the sterility of hybrids - Sterility not a special endowment , but incidental on other differences , not ...
Página 2
... sterility of species when first crossed , and the sterility of the hybrids produced from them . Pure species have of course their organs of reproduc- tion in a perfect condition , yet when intercrossed they produce either few or no ...
... sterility of species when first crossed , and the sterility of the hybrids produced from them . Pure species have of course their organs of reproduc- tion in a perfect condition , yet when intercrossed they produce either few or no ...
Página 3
... sterility . Kölreuter makes the rule universal ; but then he cuts the knot , for in ten cases in which he found two forms , considered by most authors as distinct species , quite fertile to- gether , he unhesitatingly ranks them as ...
... sterility . Kölreuter makes the rule universal ; but then he cuts the knot , for in ten cases in which he found two forms , considered by most authors as distinct species , quite fertile to- gether , he unhesitatingly ranks them as ...
Página 4
... sterility of various species when crossed is so different in degree and graduates away so insensibly , and , on the other hand , that the fertility of pure species is so easily affected by various circumstances , that for all practical ...
... sterility of various species when crossed is so different in degree and graduates away so insensibly , and , on the other hand , that the fertility of pure species is so easily affected by various circumstances , that for all practical ...
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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