The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeAppleton, 1898 - 432 páginas |
Dentro del libro
Resultados 6-10 de 52
Página 73
... more distinct from other allied genera . What geological research has not revealed , is the former existence of infinitely numerous gradations , as fine as existing varieties , con- 31 CHAP . X. ] IN ANY SINGLE FORMATION . 73.
... more distinct from other allied genera . What geological research has not revealed , is the former existence of infinitely numerous gradations , as fine as existing varieties , con- 31 CHAP . X. ] IN ANY SINGLE FORMATION . 73.
Página 77
... genera or families , have really started into life at once , the fact would be fatal to the theory of evolution through natural selection . For the development by this means of a group of forms , all of which are descended from some one ...
... genera or families , have really started into life at once , the fact would be fatal to the theory of evolution through natural selection . For the development by this means of a group of forms , all of which are descended from some one ...
Página 90
... genera and classes have not changed at the same rate , or in the same degree . In the older tertiary beds a few living shells may still be found in the midst of a multitude of extinct forms . Falconer has given a striking instance of a ...
... genera and classes have not changed at the same rate , or in the same degree . In the older tertiary beds a few living shells may still be found in the midst of a multitude of extinct forms . Falconer has given a striking instance of a ...
Página 93
... genera and families , fol- low the same general rules in their appearance and dis- appearance as do single species , changing more or less quickly , and in a greater or lesser degree . A group , when it has once disappeared , never ...
... genera and families , fol- low the same general rules in their appearance and dis- appearance as do single species , changing more or less quickly , and in a greater or lesser degree . A group , when it has once disappeared , never ...
Página 94
... genera within a family , be represented by a vertical line of vary- ing thickness , ascending through the successive geologi- cal formations , in which the species are found , the line will sometimes falsely appear to begin at its lower ...
... genera within a family , be represented by a vertical line of vary- ing thickness , ascending through the successive geologi- cal formations , in which the species are found , the line will sometimes falsely appear to begin at its lower ...
Otras ediciones - Ver todas
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