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 3
... 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 about a ...
... 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 about a ...
Página 5
... nearly all these cases by an independent cause , namely , by too close interbreeding . I have made so many experiments and collected so many facts , show- ing on the one hand that an occasional cross with a dis- tinct individual or ...
... nearly all these cases by an independent cause , namely , by too close interbreeding . I have made so many experiments and collected so many facts , show- ing on the one hand that an occasional cross with a dis- tinct individual or ...
Página 12
... nearly complete or even quite complete fertility ; and , as we have seen , in certain abnormal cases , even to an excess of fertility , beyond that which the plant's own pollen produces . So in hybrids themselves , there are some which ...
... nearly complete or even quite complete fertility ; and , as we have seen , in certain abnormal cases , even to an excess of fertility , beyond that which the plant's own pollen produces . So in hybrids themselves , there are some which ...
Página 23
... nearly the same in all cases . We will now look a little closer at the probable na- ture of the differences between species which induce sterility in first crosses and in hybrids . In the case of first crosses , the greater or less ...
... nearly the same in all cases . We will now look a little closer at the probable na- ture of the differences between species which induce sterility in first crosses and in hybrids . In the case of first crosses , the greater or less ...
Página 24
... nearly mature , but the young chickens had been unable to break through the shell . Of the chickens which were born , more than four - fifths died within the first few days , or at latest weeks , " with- out any obvious cause ...
... nearly mature , but the young chickens had been unable to break through the shell . Of the chickens which were born , more than four - fifths died within the first few days , or at latest weeks , " with- out any obvious cause ...
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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