The Origin of Species by Means of Natural Selection: Or, The Preservation of Favored Races in the Struggle for Life, Volumen2D. Appleton, 1898 |
Dentro del libro
Resultados 1-5 de 74
Página
... 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 the forms of life throughout the world ...
... 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 the forms of life throughout the world ...
Página 25
... changes of conditions with unimpaired fer- tility ; and certain species in a group will produce un- usually fertile hybrids . No one can tell , till he tries , whether any particular animal will breed under confine- ment , or any exotic ...
... changes of conditions with unimpaired fer- tility ; and certain species in a group will produce un- usually fertile hybrids . No one can tell , till he tries , whether any particular animal will breed under confine- ment , or any exotic ...
Página 27
... changes in the conditions of life are beneficial to all living things . We see this acted on by farmers and ... change in their habits of life . Again , both with plants and animals , there is the clearest evidence that a cross between ...
... changes in the conditions of life are beneficial to all living things . We see this acted on by farmers and ... change in their habits of life . Again , both with plants and animals , there is the clearest evidence that a cross between ...
Página 28
... changes in the conditions of life benefit all organic be- ings , and on the other hand , that slight crosses , that ... change in their condi- tions , very frequently are rendered more or less sterile ; and we know that a cross between ...
... changes in the conditions of life benefit all organic be- ings , and on the other hand , that slight crosses , that ... change in their condi- tions , very frequently are rendered more or less sterile ; and we know that a cross between ...
Página 29
... change , the vital forces gain in power . Reciprocal Dimorphism and Trimorphism . This subject may be here briefly discussed , and will be found to throw some light on hybridism . Several plants belonging to distinct orders present two ...
... change , the vital forces gain in power . Reciprocal Dimorphism and Trimorphism . This subject may be here briefly discussed , and will be found to throw some light on hybridism . Several plants belonging to distinct orders present two ...
Otras ediciones - Ver todas
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