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 18
... doubt that they have all descended from the common wild duck and rabbit . The doctrine of the origin of our several domestic races from several aboriginal stocks , has been carried to an absurd extreme by some authors . They believe ...
... doubt that they have all descended from the common wild duck and rabbit . The doctrine of the origin of our several domestic races from several aboriginal stocks , has been carried to an absurd extreme by some authors . They believe ...
Página 19
... doubt that a race may be modified by occasional crosses , if aided by the careful selection of those individual mongrels , which present any desired character ; but that a race could be obtained nearly intermediate between two extremely ...
... doubt that a race may be modified by occasional crosses , if aided by the careful selection of those individual mongrels , which present any desired character ; but that a race could be obtained nearly intermediate between two extremely ...
Página 25
... doubt that all our domestic breeds have descended from the Columba livia with its geographical sub - species . In favour of this view , I may add , firstly , that C. livia , or the rock - pigeon , has been found capable of domestication ...
... doubt that all our domestic breeds have descended from the Columba livia with its geographical sub - species . In favour of this view , I may add , firstly , that C. livia , or the rock - pigeon , has been found capable of domestication ...
Página 31
... doubt that the continued selection of slight variations , either in the leaves , the flowers , or the fruit , will produce races differing from each other chiefly in these characters . It may be objected that the principle of selection ...
... doubt that the continued selection of slight variations , either in the leaves , the flowers , or the fruit , will produce races differing from each other chiefly in these characters . It may be objected that the principle of selection ...
Página 32
... doubt that this process , con- tinued during centuries , would improve and modify any breed , in the same way as Bakewell , Collins , etc. , by this very same process , only carried on more methodically , did greatly modify , even ...
... doubt that this process , con- tinued during centuries , would improve and modify any breed , in the same way as Bakewell , Collins , etc. , by this very same process , only carried on more methodically , did greatly modify , even ...
Otras ediciones - Ver todas
On the Origin of Species by Means of Natural Selection: or the Preservation ... Charles Darwin Vista previa limitada - 2023 |
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