The Origin of Species by Means of Natural Selection: Or, The Preservation of Favored Races in the Struggle for Life, Volumen2D. Appleton, 1898 |
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Página 24
... stages of development and then perish like the embryos pro- duced by a cross between distinct species . Until becom- ing acquainted with these facts , I was unwilling to be- lieve in the frequent early death of hybrid embryos ; for ...
... stages of development and then perish like the embryos pro- duced by a cross between distinct species . Until becom- ing acquainted with these facts , I was unwilling to be- lieve in the frequent early death of hybrid embryos ; for ...
Página 67
... stages of the same formation throughout Europe been correlated with perfect accuracy . We may safely infer that with marine animals of all kinds there has been a large amount of migration due to climatal and other changes ; and when we ...
... stages of the same formation throughout Europe been correlated with perfect accuracy . We may safely infer that with marine animals of all kinds there has been a large amount of migration due to climatal and other changes ; and when we ...
Página 71
... stages of the same formation . Some experienced conchologists are now sinking many of the very fine species of D'Orbigny and others into the rank of varieties ; and on this view we do find the kind of evidence of change which on the ...
... stages of the same formation . Some experienced conchologists are now sinking many of the very fine species of D'Orbigny and others into the rank of varieties ; and on this view we do find the kind of evidence of change which on the ...
Página 72
... stages of transition between any two forms , is small , for the successive changes are supposed to have been local or confined to some one spot . Most marine ani- mals have a wide range ; and we have seen that with plants it is those ...
... stages of transition between any two forms , is small , for the successive changes are supposed to have been local or confined to some one spot . Most marine ani- mals have a wide range ; and we have seen that with plants it is those ...
Página 76
... stages of the same formation , they would , accord- ing to the principles followed by many palæontologists , be ranked as new and distinct species . If then there be some degree of truth in these re- marks , we have no right to expect ...
... stages of the same formation , they would , accord- ing to the principles followed by many palæontologists , be ranked as new and distinct species . If then there be some degree of truth in these re- marks , we have no right to expect ...
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Términos y frases comunes
admit affinity allied species ancient animals appear Archipelago arctic areas become believe belonging birds Cambrian changes characters cies classification climate closely allied 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 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 palæontologists Palæozoic parent parent-form peculiar perfect pistil plants pollen present probably produced quadrupeds reciprocal crosses regions remains remarked reproductive resemblance rocks rudimentary organs seeds Silurian South America stage stamens sterility structure successive suppose terrestrial tertiary theory tion variations varieties whilst whole widely different wings