The Origin of Species by Means of Natural Selection: Or, The Preservation of Favored Races in the Struggle for Life, Volumen2AMS Press, 1972 |
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Página 4
... evidence advanced by our best botanists on the question whether certain doubtful forms should be ranked as species or varieties , with the evidence from fertility adduced by different hybridisers , or by the same observer from ...
... evidence advanced by our best botanists on the question whether certain doubtful forms should be ranked as species or varieties , with the evidence from fertility adduced by different hybridisers , or by the same observer from ...
Página 37
... evidence of the existence of a certain amount of sterility in the few following cases , which I will briefly abstract . The evidence is at least as good as that from which we believe in the sterility of a multitude of species . The evidence ...
... evidence of the existence of a certain amount of sterility in the few following cases , which I will briefly abstract . The evidence is at least as good as that from which we believe in the sterility of a multitude of species . The evidence ...
Página 77
... evidence may be implicitly trusted ; negative evidence is worthless , as experience has so often shown . We continually forget how large the world is , compared with the area over which our geological formations have been carefully ...
... evidence may be implicitly trusted ; negative evidence is worthless , as experience has so often shown . We continually forget how large the world is , compared with the area over which our geological formations have been carefully ...
Contenido
CONTENTS OF VOL | 1 |
CHAPTER X | 48 |
CHAPTER XII | 129 |
Derechos de autor | |
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Términos y frases comunes
accumulated adapted admit adult affinity allied species ancient animals appear Archipelago arctic areas become beds believe birds breeds Cambrian changes characters classification climate closely allied continent crustaceans degree deposited difficulty distant distinct species domestic doubt embryo 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 seeds Silurian slight South America species belonging stage stamens sterility structure successive suppose terrestrial tertiary tion variations varieties whilst widely different wings