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 21
... pigeon , they must have descended from at least seven or eight aboriginal stocks ; for it is im- possible to make the present domestic breeds by the crossing of any lesser number : how , for instance VARIATION UNDER DOMESTICATION 21.
... pigeon , they must have descended from at least seven or eight aboriginal stocks ; for it is im- possible to make the present domestic breeds by the crossing of any lesser number : how , for instance VARIATION UNDER DOMESTICATION 21.
Página 22
Or The Preservation of Favoured Races in the Struggle for Life Charles Darwin. crossing of any lesser number : how , for instance , could a pouter be produced by crossing two breeds unless one of the parent - stocks possessed the ...
Or The Preservation of Favoured Races in the Struggle for Life Charles Darwin. crossing of any lesser number : how , for instance , could a pouter be produced by crossing two breeds unless one of the parent - stocks possessed the ...
Página 23
... crossed , neither of which is blue or has any of the above - specified marks , the mongrel offspring are very apt suddenly to acquire these characters ; for instance , I crossed some uniformly white fantails with some uniformly black ...
... crossed , neither of which is blue or has any of the above - specified marks , the mongrel offspring are very apt suddenly to acquire these characters ; for instance , I crossed some uniformly white fantails with some uniformly black ...
Página 24
... crossed by the rock - pigeon : I say within a dozen or twenty generations , for we know of no fact counten- ancing the belief that the child ever reverts to some one ancestor , removed by a greater number of genera- tions . In a breed ...
... crossed by the rock - pigeon : I say within a dozen or twenty generations , for we know of no fact counten- ancing the belief that the child ever reverts to some one ancestor , removed by a greater number of genera- tions . In a breed ...
Página 25
... crossed ; the mongrel offspring being perfectly fertile ; -from these several reasons , taken together , I can feel no doubt that all our domestic breeds have descended from the Columba livia with its geographical sub - species . In ...
... crossed ; the mongrel offspring being perfectly fertile ; -from these several reasons , taken together , I can feel no doubt that all our domestic breeds have descended from the Columba livia with its geographical sub - species . In ...
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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