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 40
... mongrels and the more fertile hybrids are propagated for several generations , an extreme amount of variability in the offspring in both cases is notorious ; but some few instances of both hybrids and mongrels long retaining a uniform ...
... mongrels and the more fertile hybrids are propagated for several generations , an extreme amount of variability in the offspring in both cases is notorious ; but some few instances of both hybrids and mongrels long retaining a uniform ...
Página 41
... mongrels and hybrids : Gärtner states that mongrels are more liable than hybrids to revert to either parent - form ; but this , if it be true , is certainly only a difference in degree . Moreover , Gärtner expressly states that hybrids ...
... mongrels and hybrids : Gärtner states that mongrels are more liable than hybrids to revert to either parent - form ; but this , if it be true , is certainly only a difference in degree . Moreover , Gärtner expressly states that hybrids ...
Página 42
... mongrel plants from a reciprocal cross . Both hybrids and mongrels can be reduced to either pure parent - form , by repeated crosses in successive generations with either parent . These several remarks are apparently applicable to ...
... mongrel plants from a reciprocal cross . Both hybrids and mongrels can be reduced to either pure parent - form , by repeated crosses in successive generations with either parent . These several remarks are apparently applicable to ...
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