The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeAppleton, 1898 - 432 páginas |
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Página 2
... parent- species . In treating this subject , two classes of facts , to a large extent fundamentally different , have ... parents , when crossed , and likewise the fertility of their mongrel off- spring , is , with reference to my theory ...
... parent- species . In treating this subject , two classes of facts , to a large extent fundamentally different , have ... parents , when crossed , and likewise the fertility of their mongrel off- spring , is , with reference to my theory ...
Página 3
... parent - species in a state of nature . But causes of serious error here intervene : a plant , to be hybridised , must be castrated , and , what is often more important , must be secluded in order to prevent pollen being brought to it ...
... parent - species in a state of nature . But causes of serious error here intervene : a plant , to be hybridised , must be castrated , and , what is often more important , must be secluded in order to prevent pollen being brought to it ...
Página 4
... enabled to rear some hybrids , carefully guarding them from a cross with either pure parent , for six or seven , and in one case for ten generations , yet he asserts positively that their fer- 4 [ CHAP . IX . HYBRIDISM .
... enabled to rear some hybrids , carefully guarding them from a cross with either pure parent , for six or seven , and in one case for ten generations , yet he asserts positively that their fer- 4 [ CHAP . IX . HYBRIDISM .
Página 5
... parents , this is often transmitted in an augmented degree to the offspring ; and both sexual elements in hybrid plants ... parent - species , or other allied hybrids , generally grow in the same garden , the visits of insects must be ...
... parents , this is often transmitted in an augmented degree to the offspring ; and both sexual elements in hybrid plants ... parent - species , or other allied hybrids , generally grow in the same garden , the visits of insects must be ...
Página 6
... parent - species - as are Kölreuter and Gärtner that some degree of sterility between distinct species is a universal law of nature . He experimented on some of the very same species as did Gärtner . The difference in their results may ...
... parent - species - as are Kölreuter and Gärtner that some degree of sterility between distinct species is a universal law of nature . He experimented on some of the very same species as did Gärtner . The difference in their results may ...
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Términos y frases comunes
admit affinity allied species ancient animals appear Archipelago arctic areas become believe birds Cambrian changes characters cies classification climate closely allied common progenitor 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 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 sediment seeds Silurian South America stage stamens sterility structure successive suppose terrestrial tertiary theory tion variations varieties whilst widely different wings