On 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 1-5 de 33
Página 7
... peculiar condition . So that with some species , certain abnormal individuals , and in other species all the individuals , can actually be hybridised much more readily than they can be fertilised by pollen from the same individual plant ...
... peculiar condition . So that with some species , certain abnormal individuals , and in other species all the individuals , can actually be hybridised much more readily than they can be fertilised by pollen from the same individual plant ...
Página 17
... peculiar and lim- ited a nature , that , in reciprocal crosses between the same two species , the male sexual element of the one will often freely act on the female sexual element of the other , but not in a reversed direction . It will ...
... peculiar and lim- ited a nature , that , in reciprocal crosses between the same two species , the male sexual element of the one will often freely act on the female sexual element of the other , but not in a reversed direction . It will ...
Página 21
... peculiar state of the reproductive system could hardly have been ad- vantageous to either species . In considering the probability of natural selection having come into action , in rendering species mutually sterile , the greatest ...
... peculiar state of the reproductive system could hardly have been ad- vantageous to either species . In considering the probability of natural selection having come into action , in rendering species mutually sterile , the greatest ...
Página 30
... peculiarly coloured variety , and all the seedlings were similarly coloured ; this shows that the legitimate pollen , though applied twenty - four hours subsequently , had wholly destroyed or prevented the action of the previously ...
... peculiarly coloured variety , and all the seedlings were similarly coloured ; this shows that the legitimate pollen , though applied twenty - four hours subsequently , had wholly destroyed or prevented the action of the previously ...
Página 36
... peculiar constitution , sterility might occasionally be thus caused . Thus , as I believe , we can understand why with domesticated animals varieties have not been produced which are mutually sterile ; and why with plants only a few ...
... peculiar constitution , sterility might occasionally be thus caused . Thus , as I believe , we can understand why with domesticated animals varieties have not been produced which are mutually sterile ; and why with plants only a few ...
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