On the Origin of Species by Means of Natural Selection, Or, The Preservation of Favoured Races in the Struggle for LifeAppleton, 1898 |
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Página 36
... becomes in the highest degree improbable that similar conditions long - continued should likewise induce this ... become mutually infertile when crossed , but why this has so generally occurred with natural varieties , as soon as ...
... becomes in the highest degree improbable that similar conditions long - continued should likewise induce this ... become mutually infertile when crossed , but why this has so generally occurred with natural varieties , as soon as ...
Página 45
... distinct species , the sexual elements should so generally have become more or less modified , leading to their mutual infertility , we do not know ; but it seems to stand in some close relation to species having CHAP . IX . ] 45 SUMMARY .
... distinct species , the sexual elements should so generally have become more or less modified , leading to their mutual infertility , we do not know ; but it seems to stand in some close relation to species having CHAP . IX . ] 45 SUMMARY .
Página 47
... become sterile , yet the facts given in this chapter do not seem to me opposed to the belief that species aboriginally existed as varie- ties . CHAPTER X. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD . CHAP . IX . ] 47 SUMMARY .
... become sterile , yet the facts given in this chapter do not seem to me opposed to the belief that species aboriginally existed as varie- ties . CHAPTER X. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD . CHAP . IX . ] 47 SUMMARY .
Página 50
... become so much modified , that , if we had no historical or indirect evidence regarding their origin , it would not have been possible to have determined , from a mere comparison of their structure with that of the rock- pigeon , C ...
... become so much modified , that , if we had no historical or indirect evidence regarding their origin , it would not have been possible to have determined , from a mere comparison of their structure with that of the rock- pigeon , C ...
Página 58
... become embedded , if in sand or gravel , will , when the beds are upraised , generally be dissolved by the percolation of rain - water charged with carbolic acid . Some of the many kinds of animals which live on the beach between high ...
... become embedded , if in sand or gravel , will , when the beds are upraised , generally be dissolved by the percolation of rain - water charged with carbolic acid . Some of the many kinds of animals which live on the beach between high ...
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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