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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... species - On their different rates of change - Species once lost do not reappear- Groups of species follow the same general rules in their ap- pearance and disappearance as do single species - On extinction -On simultaneous changes in ...
... species - On their different rates of change - Species once lost do not reappear- Groups of species follow the same general rules in their ap- pearance and disappearance as do single species - On extinction -On simultaneous changes in ...
Página 2
... species . In treating this subject , two classes of facts , to a large extent fundamentally different , have generally been confounded ; namely , the sterility of species when first crossed , and the sterility of the hybrids produced ...
... species . In treating this subject , two classes of facts , to a large extent fundamentally different , have generally been confounded ; namely , the sterility of species when first crossed , and the sterility of the hybrids produced ...
Página 4
... species are really so sterile , when intercrossed , as he be- lieved . It is certain , on the one hand , that the sterility of various species when crossed is so different in degree and graduates away so insensibly , and , on the other ...
... species are really so sterile , when intercrossed , as he be- lieved . It is certain , on the one hand , that the sterility of various species when crossed is so different in degree and graduates away so insensibly , and , on the other ...
Página 7
... 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 other plants or ...
... 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 other plants or ...
Página 10
... species , exists , they must certainly be highly or perfectly fertile . With our domesticated animals , the various races when crossed together are quite fertile ; yet in many cases they are descended from two or more wild species ...
... species , exists , they must certainly be highly or perfectly fertile . With our domesticated animals , the various races when crossed together are quite fertile ; yet in many cases they are descended from two or more wild species ...
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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