The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeAppleton, 1898 - 432 páginas |
Dentro del libro
Resultados 1-5 de 18
Página 14
... reciprocal crosses . Such cases are highly important , for they prove that the capacity in any two species to cross is often completely independ- ent of their systematic affinity , that is of any differ- ence in their structure or ...
... reciprocal crosses . Such cases are highly important , for they prove that the capacity in any two species to cross is often completely independ- ent of their systematic affinity , that is of any differ- ence in their structure or ...
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 16
... cross between any two species is not always governed by their syste- matic affinity or degree of resemblance to each other . This latter statement is clearly proved by the differ- ence in the result of reciprocal crosses between the ...
... cross between any two species is not always governed by their syste- matic affinity or degree of resemblance to each other . This latter statement is clearly proved by the differ- ence in the result of reciprocal crosses between the ...
Página 17
... crosses and of hybrids is simply incidental or dependent on unknown differences in their reproductive systems ; the differences being of so peculiar and lim- ited a nature , that , in reciprocal crosses between the same two species ...
... crosses and of hybrids is simply incidental or dependent on unknown differences in their reproductive systems ; the differences being of so peculiar and lim- ited a nature , that , in reciprocal crosses between the same two species ...
Página 18
... same two species in crossing ; so Sageret believes this to be the case with different individuals of the same two spe- cies in being grafted together . As in reciprocal crosses 18 LAWS GOVERNING THE STERILITY [ CHAP . IX .
... same two species in crossing ; so Sageret believes this to be the case with different individuals of the same two spe- cies in being grafted together . As in reciprocal crosses 18 LAWS GOVERNING THE STERILITY [ CHAP . IX .
Otras ediciones - Ver todas
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