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 v
... present day - On the nature of extinct intermediate varieties ; on their number- On the lapse of time , as inferred from the rate of denudation and of deposition — On the lapse of time as estimated by years -On the poorness of our ...
... present day - On the nature of extinct intermediate varieties ; on their number- On the lapse of time , as inferred from the rate of denudation and of deposition — On the lapse of time as estimated by years -On the poorness of our ...
Página vi
... present chapter · Page 89 CHAPTER XII . GEOGRAPHICAL DISTRIBUTION . Present distribution cannot be accounted for by differences in physical conditions - Importance of barriers - Affinity of the productions of the same continent ...
... present chapter · Page 89 CHAPTER XII . GEOGRAPHICAL DISTRIBUTION . Present distribution cannot be accounted for by differences in physical conditions - Importance of barriers - Affinity of the productions of the same continent ...
Página 11
... present state of knowledge , be con- sidered as absolutely universal . Laws governing the Sterility of first Crosses and of Hybrids . We will now consider a little more in detail the laws governing the sterility of first crosses and of ...
... present state of knowledge , be con- sidered as absolutely universal . Laws governing the Sterility of first Crosses and of Hybrids . We will now consider a little more in detail the laws governing the sterility of first crosses and of ...
Página 29
... present two forms , which exist in about equal numbers and which differ in no respect except in their reproductive organs ; one form having a long pistil with short stamens , the other a short pistil with long stamens ; the two having ...
... present two forms , which exist in about equal numbers and which differ in no respect except in their reproductive organs ; one form having a long pistil with short stamens , the other a short pistil with long stamens ; the two having ...
Página 36
... present subject is not , as it appears to me , why domestic varieties have not become mutually infertile when crossed , but why this has so generally occurred with natural varieties , as soon as they have been permanently modified in a ...
... present subject is not , as it appears to me , why domestic varieties have not become mutually infertile when crossed , but why this has so generally occurred with natural varieties , as soon as they have been permanently modified in a ...
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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