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 28
... perfect and as useful as we now see them ; indeed , in several cases , we know that this has not been their history . The key is man's power of accumulative selection : nature gives successive variations ; man adds them up in certain ...
... perfect and as useful as we now see them ; indeed , in several cases , we know that this has not been their history . The key is man's power of accumulative selection : nature gives successive variations ; man adds them up in certain ...
Página 29
... perfect in itself , and then had given it existence . ' That most skilful breeder , Sir John Sebright , used to say , with respect to pigeons , that he would produce any given feather in three years , but it would take him six years to ...
... perfect in itself , and then had given it existence . ' That most skilful breeder , Sir John Sebright , used to say , with respect to pigeons , that he would produce any given feather in three years , but it would take him six years to ...
Página 86
... perfect manner to each other , by the continued pre- servation of individuals presenting mutual and slightly favourable deviations of structure . I am well aware that this doctrine of natural selec- tion , exemplified in the above ...
... perfect manner to each other , by the continued pre- servation of individuals presenting mutual and slightly favourable deviations of structure . I am well aware that this doctrine of natural selec- tion , exemplified in the above ...
Página 154
... perfect - The law of Unity of Type and of the Conditions of Existence embraced by the theory of Natural Selection . LONG before having arrived at this part of my work , a crowd of difficulties will have occurred to the reader . Some of ...
... perfect - The law of Unity of Type and of the Conditions of Existence embraced by the theory of Natural Selection . LONG before having arrived at this part of my work , a crowd of difficulties will have occurred to the reader . Some of ...
Página 155
... perfect than is generally supposed ; the imperfection of the record being chiefly due to organic beings not inhabiting profound depths of the sea , and to their remains being embedded and preserved to a future age only in masses of ...
... perfect than is generally supposed ; the imperfection of the record being chiefly due to organic beings not inhabiting profound depths of the sea , and to their remains being embedded and preserved to a future age only in masses of ...
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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