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 23
... recently given the results of an examination of about 500 eggs produced from various crosses between three species of Gallus and their hybrids ; the majority of these eggs had been fertilised ; and in the majority of the fertilised eggs ...
... recently given the results of an examination of about 500 eggs produced from various crosses between three species of Gallus and their hybrids ; the majority of these eggs had been fertilised ; and in the majority of the fertilised eggs ...
Página 24
... recently given some striking cases with hybrid willows . It may be here worth noticing that in some cases of parthenogenesis , the embryos within the eggs of silk moths which had not been fertilised , pass through their early stages of ...
... recently given some striking cases with hybrid willows . It may be here worth noticing that in some cases of parthenogenesis , the embryos within the eggs of silk moths which had not been fertilised , pass through their early stages of ...
Página 40
... recent variability , which would often continue and would augment that arising from the act of crossing . The slight variability of hybrids in the first generation , in contrast with that in the succeeding generations , is a curious ...
... recent variability , which would often continue and would augment that arising from the act of crossing . The slight variability of hybrids in the first generation , in contrast with that in the succeeding generations , is a curious ...
Página 53
... recently learnt from the obser- vations of Ramsay , in the van of many excellent ob- servers of Jukes , Geikie , Croll , and others , that sub- aerial degradation is a much more important agency than coast - action , or the power of the ...
... recently learnt from the obser- vations of Ramsay , in the van of many excellent ob- servers of Jukes , Geikie , Croll , and others , that sub- aerial degradation is a much more important agency than coast - action , or the power of the ...
Página 59
... recently not a land - shell was known belonging to either of these vast periods , with the exception of one species discovered by Sir C. Lyell and Dr. Dawson in the carboniferous strata of North America ; but now land - shells have been ...
... recently not a land - shell was known belonging to either of these vast periods , with the exception of one species discovered by Sir C. Lyell and Dr. Dawson in the carboniferous strata of North America ; but now land - shells have been ...
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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