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
... formation ; so that , in fact , ' sports ' support my view , that variability may be largely attri- buted to the ovules or pollen , or to both , having been affected by the treatment of the parent prior to the VARIATION UNDER DOMESTICATION.
... formation ; so that , in fact , ' sports ' support my view , that variability may be largely attri- buted to the ovules or pollen , or to both , having been affected by the treatment of the parent prior to the VARIATION UNDER DOMESTICATION.
Página 38
... formation of new races , -at least , in a country which is already stocked with other races . In this respect enclosure of the land plays a part . Wandering savages or the inhabitants of open plains rarely possess more than one breed of ...
... formation of new races , -at least , in a country which is already stocked with other races . In this respect enclosure of the land plays a part . Wandering savages or the inhabitants of open plains rarely possess more than one breed of ...
Página 39
... formation of new breeds . Pigeons , I may add , can be propagated in great numbers and at a very quick rate , and inferior birds may be freely rejected , as when killed they serve for food . On the other hand , cats , from their ...
... formation of new breeds . Pigeons , I may add , can be propagated in great numbers and at a very quick rate , and inferior birds may be freely rejected , as when killed they serve for food . On the other hand , cats , from their ...
Página 40
... formation of new sub - breeds ; but the importance of the crossing of varieties has , I believe , been greatly exaggerated , both in regard to animals and to those plants which are propagated by seed . In plants which are temporarily ...
... formation of new sub - breeds ; but the importance of the crossing of varieties has , I believe , been greatly exaggerated , both in regard to animals and to those plants which are propagated by seed . In plants which are temporarily ...
Página 87
... formation of the longest lines of inland cliffs . Natural selection can act only by the preservation and accumulation of infinitesimally small inherited modi- fications , each profitable to the preserved being ; and as modern geology ...
... formation of the longest lines of inland cliffs . Natural selection can act only by the preservation and accumulation of infinitesimally small inherited modi- fications , each profitable to the preserved being ; and as modern geology ...
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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