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 16
... hybrids are almost always utterly sterile , even when the other hybrids raised from seed from the same capsule have a considerable degree of fertility . These facts show how completely the fertility of a hybrid may be independent of its ...
... hybrids are almost always utterly sterile , even when the other hybrids raised from seed from the same capsule have a considerable degree of fertility . These facts show how completely the fertility of a hybrid may be independent of its ...
Página 40
... hybrids ; but Gärtner admits that hybrids from species which have long been cultivated are often variable in the first generation ; and I have myself seen striking instances of this fact . Gärtner further admits that hybrids between ...
... hybrids ; but Gärtner admits that hybrids from species which have long been cultivated are often variable in the first generation ; and I have myself seen striking instances of this fact . Gärtner further admits that hybrids between ...
Página 41
... hybrids themselves have their reproductive systems seriously affected , and their descendants are highly variable . But to return to our comparison of mongrels and hybrids : Gärtner states that mongrels are more liable than hybrids to ...
... hybrids themselves have their reproductive systems seriously affected , and their descendants are highly variable . But to return to our comparison of mongrels and hybrids : Gärtner states that mongrels are more liable than hybrids to ...
Contenido
CONTENTS OF VOL | 1 |
CHAPTER X | 48 |
CHAPTER XII | 129 |
Derechos de autor | |
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Otras ediciones - Ver todas
The Origin of Species by Means of Natural Selection: Or, The Preservation of ... Charles Darwin Vista de fragmentos - 1962 |
The Origin of Species by Means of Natural Selection: Or, The Preservation of ... Charles Darwin Vista de fragmentos - 1963 |
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