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 34
... varieties produced under nature , if two forms hitherto reputed to be varieties be found in any degree sterile together , they are at once ranked by most naturalists as species . For instance , the blue and red pimpernel , which are ...
... varieties produced under nature , if two forms hitherto reputed to be varieties be found in any degree sterile together , they are at once ranked by most naturalists as species . For instance , the blue and red pimpernel , which are ...
Página 38
... varieties of gourd , which like the maize has separated sexes , and he asserts that their mutual fertilisation is by so much the less easy as their differences are greater . How far these experiments may be trusted , I know not ; but ...
... varieties of gourd , which like the maize has separated sexes , and he asserts that their mutual fertilisation is by so much the less easy as their differences are greater . How far these experiments may be trusted , I know not ; but ...
Página 39
... varieties , and which he tested by the severest trial , namely , by reciprocal crosses , and he found their mongrel offspring erfectly fertile . But one of these five varieties , when used either as the father or mother , and crossed ...
... varieties , and which he tested by the severest trial , namely , by reciprocal crosses , and he found their mongrel offspring erfectly fertile . But one of these five varieties , when used either as the father or mother , and crossed ...
Contenido
CONTENTS OF VOL | 1 |
CHAPTER X | 48 |
CHAPTER XII | 129 |
Derechos de autor | |
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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 - 1962 |
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