On the Origin of Species by Means of Natural Selection, Or, The Preservation of Favoured Races in the Struggle for LifeAppleton, 1898 |
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Página 2
... reproductive systems of the parent- species . In treating this subject , two classes of facts , to a large extent fundamentally different , have generally been confounded ; namely , the sterility of species when first crossed , and the ...
... reproductive systems of the parent- species . In treating this subject , two classes of facts , to a large extent fundamentally different , have generally been confounded ; namely , the sterility of species when first crossed , and the ...
Página 14
... independ- ent of their systematic affinity , that is of any differ- ence in their structure or constitution , excepting in their reproductive systems . The diversity of the result in 14 LAWS GOVERNING THE STERILITY [ CHAP . IX .
... independ- ent of their systematic affinity , that is of any differ- ence in their structure or constitution , excepting in their reproductive systems . The diversity of the result in 14 LAWS GOVERNING THE STERILITY [ CHAP . IX .
Página 15
Charles Darwin. their reproductive systems . The diversity of the result in reciprocal crosses between the same two species was long ago observed by Kölreuter . To give an instance : Mirabilis jalapa can easily be fertilised by the ...
Charles Darwin. their reproductive systems . The diversity of the result in reciprocal crosses between the same two species was long ago observed by Kölreuter . To give an instance : Mirabilis jalapa can easily be fertilised by the ...
Página 17
... reproductive systems ; the differences being of so peculiar and lim- ited a nature , that , in reciprocal crosses between the same two species , the male sexual element of the one will often freely act on the female sexual element of ...
... reproductive systems ; the differences being of so peculiar and lim- ited a nature , that , in reciprocal crosses between the same two species , the male sexual element of the one will often freely act on the female sexual element of ...
Página 19
... reproductive organs in an imperfect con- dition , is a different case from the difficulty of uniting two pure species , which have their reproductive organs perfect ; yet these two distinct classes of cases run to a large extent ...
... reproductive organs in an imperfect con- dition , is a different case from the difficulty of uniting two pure species , which have their reproductive organs perfect ; yet these two distinct classes of cases run to a large extent ...
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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