The Origin of Species by Means of Natural Selection: Or, The Preservation of Favored Races in the Struggle for Life, Volumen2D. Appleton, 1898 |
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Página 5
... respect to this decrease , it may first be noticed that when any deviation in structure or constitu- tion is common to both parents , this is often transmitted in an augmented degree to the offspring ; and both sexual elements in hybrid ...
... respect to this decrease , it may first be noticed that when any deviation in structure or constitu- tion is common to both parents , this is often transmitted in an augmented degree to the offspring ; and both sexual elements in hybrid ...
Página 9
... respect to the fertility in successive generations of the more fertile hybrid animals , I hardly know of an in- stance in which two families of the same hybrid have been raised at the same time from different parents , so as to avoid ...
... respect to the fertility in successive generations of the more fertile hybrid animals , I hardly know of an in- stance in which two families of the same hybrid have been raised at the same time from different parents , so as to avoid ...
Página 27
... respect to the sterility of hybrids ; for instance , the unequal fertility of hybrids produced from recipro- cal ... respects allied , sterility is the common result , -in the one case from the conditions of life having been disturbed ...
... respect to the sterility of hybrids ; for instance , the unequal fertility of hybrids produced from recipro- cal ... respects allied , sterility is the common result , -in the one case from the conditions of life having been disturbed ...
Página 29
... respect except in their reproductive organs ; one form having a long pistil with short stamens , the other a short ... respects ; and as in each of the three forms there are two sets of stamens , the three forms possess altogether six ...
... respect except in their reproductive organs ; one form having a long pistil with short stamens , the other a short ... respects ; and as in each of the three forms there are two sets of stamens , the three forms possess altogether six ...
Página 31
... respects , and in others which might be added , the forms of the same undoubted species when illegitimately united behave in exactly the same manner as do two distinct species when crossed . This led me carefully to observe during four ...
... respects , and in others which might be added , the forms of the same undoubted species when illegitimately united behave in exactly the same manner as do two distinct species when crossed . This led me carefully to observe during four ...
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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