On the Origin of Species by Means of Natural Selection: Or The Preservation of Favoured Races in the Struggle for LifeHumphrey Milford, Oxford University Press, 1923 - 454 páginas |
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Página 9
... Sterility has been said to be the bane of horticulture ; but on this view we owe variability to the same cause which produces sterility ; and variability is the source of all the choicest productions of the garden . I may add , that as ...
... Sterility has been said to be the bane of horticulture ; but on this view we owe variability to the same cause which produces sterility ; and variability is the source of all the choicest productions of the garden . I may add , that as ...
Página 24
... sterility : from the history of the dog I think there is some probability in this hypothesis , if applied to species closely related together , though it is unsupported by a single experiment . But to ex- tend the hypothesis so far as ...
... sterility : from the history of the dog I think there is some probability in this hypothesis , if applied to species closely related together , though it is unsupported by a single experiment . But to ex- tend the hypothesis so far as ...
Página 40
... sterility of hybrids ; but the cases of plants not propagated by seed are of little importance to us , for their endurance is only temporary . Over all these causes of Change I am convinced that the accumulative action of Selection ...
... sterility of hybrids ; but the cases of plants not propagated by seed are of little importance to us , for their endurance is only temporary . Over all these causes of Change I am convinced that the accumulative action of Selection ...
Página 219
... one general law , leading to the advancement of all organic beings , namely , multiply , vary , let the strongest live and the weakest die . CHAPTER VIII HYBRIDISM Distinction between the sterility of first crosses INSTINCT 219.
... one general law , leading to the advancement of all organic beings , namely , multiply , vary , let the strongest live and the weakest die . CHAPTER VIII HYBRIDISM Distinction between the sterility of first crosses INSTINCT 219.
Página 220
... sterility of first crosses and of hybrids- Sterility various in degree , not universal , affected by close inter- breeding , removed by domestication - Laws governing the sterility of hybrids - Sterility not a special endowment , but ...
... sterility of first crosses and of hybrids- Sterility various in degree , not universal , affected by close inter- breeding , removed by domestication - Laws governing the sterility of hybrids - Sterility not a special endowment , but ...
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Términos y frases comunes
accumulated adapted affinities allied species America amount analogous ancient appear Archipelago become bees believe birds breeds cause cells characters cirripedes climate closely allied colour common parent continuous crossed crustaceans degree difficulty distinct species divergence doubt embryo endemic Europe existing exterminated extinct extremely facts favourable fertility flowers formations forms fossil Gärtner genera genus geological geological period Glacial period gradations greater number groups of species habits Hence hermaphrodites hybrids hybrids produced important individuals inhabitants inherited insects instance instincts intercrossing land larvæ less living male mammals manner Marsupials migration modification modified descendants natural selection naturalists nearly nest oceanic islands offspring organisation perfect pigeons pistil plants pollen present principle probably produced progenitor ranked reciprocal crosses remarked resemble rock-pigeon rudimentary organs seeds sexual selection Silurian slight South America sterility structure struggle successive suppose swimbladder tend theory tion trees variability variation vary whole widely