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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... Means of dispersal by changes of climate and of the level of the land , and by occasional means — Dispersal during the Glacial period -Alternate Glacial periods in the North and South • 129 CHAPTER XIII . GEOGRAPHICAL DISTRIBUTION ...
... Means of dispersal by changes of climate and of the level of the land , and by occasional means — Dispersal during the Glacial period -Alternate Glacial periods in the North and South • 129 CHAPTER XIII . GEOGRAPHICAL DISTRIBUTION ...
Página 14
... mean the case , for instance , of a female - ass being first crossed by a stallion , and then a mare by a male - ass ; these two species may then be said to have been reciprocally crossed . There is often the widest possible difference ...
... mean the case , for instance , of a female - ass being first crossed by a stallion , and then a mare by a male - ass ; these two species may then be said to have been reciprocally crossed . There is often the widest possible difference ...
Página 17
... mean by sterility being incidental on other differences , and not a specially endowed quality . As the capacity of one plant to be grafted or budded on another is un- important for their welfare in a state of nature , I pre- sume that ...
... mean by sterility being incidental on other differences , and not a specially endowed quality . As the capacity of one plant to be grafted or budded on another is un- important for their welfare in a state of nature , I pre- sume that ...
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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