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 vi
... forms of life throughout the world - On the affinities of extinct species to each other and to living species - On the state of development of ancient forms— On the succession of the same types within the same areas— Summary of ...
... forms of life throughout the world - On the affinities of extinct species to each other and to living species - On the state of development of ancient forms— On the succession of the same types within the same areas— Summary of ...
Página 3
... forms , considered by most authors as distinct species , quite fertile to- gether , he unhesitatingly ranks them as varieties . ner , also , makes the rule equally universal ; and he dis- putes the entire fertility of Kölreuter's ten ...
... forms , considered by most authors as distinct species , quite fertile to- gether , he unhesitatingly ranks them as varieties . ner , also , makes the rule equally universal ; and he dis- putes the entire fertility of Kölreuter's ten ...
Página 4
... forms . It is also most instructive to compare - but I have not space here to enter on details the evidence advanced by our best botanists on the question whether certain doubtful forms should be ranked as species or varieties , with ...
... forms . It is also most instructive to compare - but I have not space here to enter on details the evidence advanced by our best botanists on the question whether certain doubtful forms should be ranked as species or varieties , with ...
Página 21
... form should have been rendered utterly impotent on a second form , whilst at the same time the male element of this second form is enabled freely to fertilise the first form ; for this peculiar state of the reproductive system could ...
... form should have been rendered utterly impotent on a second form , whilst at the same time the male element of this second form is enabled freely to fertilise the first form ; for this peculiar state of the reproductive system could ...
Página 29
... forms , which exist in about equal numbers and which differ in no respect except in their reproductive organs ; one ... forms likewise differing in the lengths of their pistils and stamens , in the size and colour of the pollen - grains ...
... forms , which exist in about equal numbers and which differ in no respect except in their reproductive organs ; one ... forms likewise differing in the lengths of their pistils and stamens , in the size and colour of the pollen - grains ...
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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