The Origin of Species by Means of Natural Selection: Or, The Preservation of Favored Races in the Struggle for Life, Volumen2D. Appleton, 1898 |
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Página 2
... plants and animals ; though the formative organs themselves are perfect in structure , as far as the microscope reveals . In the first case the two sexual elements which go to form the embryo are per- fect ; in the second case they are ...
... plants and animals ; though the formative organs themselves are perfect in structure , as far as the microscope reveals . In the first case the two sexual elements which go to form the embryo are per- fect ; in the second case they are ...
Página 3
... plants . Nearly all the plants experimented on by Gärtner were potted , and were kept in a chamber in his house . That these processes are often injurious to the fertility of a plant cannot be doubted ; for Gärtner gives in his table ...
... plants . Nearly all the plants experimented on by Gärtner were potted , and were kept in a chamber in his house . That these processes are often injurious to the fertility of a plant cannot be doubted ; for Gärtner gives in his table ...
Página 5
... plants are already affected in some degree . But I believe that their fertility has been di- minished in nearly all these cases by an independent cause , namely , by too close interbreeding . I have made so many experiments and ...
... plants are already affected in some degree . But I believe that their fertility has been di- minished in nearly all these cases by an independent cause , namely , by too close interbreeding . I have made so many experiments and ...
Página 6
... plant , would be thus effected . Moreover , whenever complicated experiments are in progress , so careful an observer as Gärtner would have castrated his hybrids , and this would have ensured ... plants of certain. 6 [ CHAP . IX . HYBRIDISM .
... plant , would be thus effected . Moreover , whenever complicated experiments are in progress , so careful an observer as Gärtner would have castrated his hybrids , and this would have ensured ... plants of certain. 6 [ CHAP . IX . HYBRIDISM .
Página 7
... plants of certain species of Lobelia , Verbascum and Passiflora , can easily be fertilised by pollen from a distinct species , but not by pollen from the same plant , though this pollen can be proved to be perfectly sound by fertilising ...
... plants of certain species of Lobelia , Verbascum and Passiflora , can easily be fertilised by pollen from a distinct species , but not by pollen from the same plant , though this pollen can be proved to be perfectly sound by fertilising ...
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Términos y frases comunes
admit affinity allied species ancient animals appear Archipelago arctic areas become believe belonging birds Cambrian changes characters cies classification climate closely allied 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 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 palæontologists Palæozoic parent parent-form peculiar perfect pistil plants pollen present probably produced quadrupeds reciprocal crosses regions remains remarked reproductive resemblance rocks rudimentary organs seeds Silurian South America stage stamens sterility structure successive suppose terrestrial tertiary theory tion variations varieties whilst whole widely different wings