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 2
... hybrids produced from them . Pure species have of course their organs of reproduc- tion in a perfect condition , yet when intercrossed they produce either few or no offspring . Hybrids , on the other hand , have their reproductive ...
... hybrids produced from them . Pure species have of course their organs of reproduc- tion in a perfect condition , yet when intercrossed they produce either few or no offspring . Hybrids , on the other hand , have their reproductive ...
Página 3
... produced by two species when first crossed , and the maximum produced by their hybrid offspring , with the average number produced by both pure parent - species in a state of nature . But causes of serious error here intervene : a plant ...
... produced by two species when first crossed , and the maximum produced by their hybrid offspring , with the average number produced by both pure parent - species in a state of nature . But causes of serious error here intervene : a plant ...
Página 6
... hybrid nature . And thus , the strange fact of an increase of fertility in the successive genera- tions of artificially fertilised hybrids ... produced a plant , which I never saw to occur in a case of its natural fecun- dation . " So that ...
... hybrid nature . And thus , the strange fact of an increase of fertility in the successive genera- tions of artificially fertilised hybrids ... produced a plant , which I never saw to occur in a case of its natural fecun- dation . " So that ...
Página 7
... produced four flowers ; three were fertilised by Herbert with their own pollen , and the fourth was subsequently fertilised by the pollen of a compound hybrid ... hybrids seed freely . For instance , Herbert asserts that 66 a hybrid from ...
... produced four flowers ; three were fertilised by Herbert with their own pollen , and the fourth was subsequently fertilised by the pollen of a compound hybrid ... hybrids seed freely . For instance , Herbert asserts that 66 a hybrid from ...
Página 8
... produces itself as perfectly as if it had been a natural species from the ... hybrid between Rhod . ponticum and catawbiense , and that this hybrid " seeds as ... hybrids themselves are , I think , more sterile . It should , however , be ...
... produces itself as perfectly as if it had been a natural species from the ... hybrid between Rhod . ponticum and catawbiense , and that this hybrid " seeds as ... hybrids themselves are , I think , more sterile . It should , however , be ...
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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