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 3
... and co- adaptation . At the commencement of my observations it seemed to me probable that a careful study of domes ticated animals and of cultivated plants would offer the best chance of making out this obscure problem . Nor INTRODUCTION.
... and co- adaptation . At the commencement of my observations it seemed to me probable that a careful study of domes ticated animals and of cultivated plants would offer the best chance of making out this obscure problem . Nor INTRODUCTION.
Página 24
... observations , purposely made , on the most distinct breeds . Now , it is difficult , perhaps impossible , to bring forward one case of the hybrid offspring of two animals clearly distinct being themselves perfectly fertile . Some ...
... observations , purposely made , on the most distinct breeds . Now , it is difficult , perhaps impossible , to bring forward one case of the hybrid offspring of two animals clearly distinct being themselves perfectly fertile . Some ...
Página 42
... observed in the indivi- duals of the same species inhabiting the same confined locality . No one supposes that all the individuals of the same species are cast in the very same mould . These individual differences are highly important ...
... observed in the indivi- duals of the same species inhabiting the same confined locality . No one supposes that all the individuals of the same species are cast in the very same mould . These individual differences are highly important ...
Página 47
... observations , he will meet with more cases of difficulty ; for he will encounter a greater number of closely - allied forms . But if his observations be widely extended , he will in the end generally be enabled to make up his own mind ...
... observations , he will meet with more cases of difficulty ; for he will encounter a greater number of closely - allied forms . But if his observations be widely extended , he will in the end generally be enabled to make up his own mind ...
Página 62
... observations which I have made , İ believe that it is the seedlings which suffer most from germinating in ground already thickly stocked with other plants . Seedlings , also , are destroyed in vast numbers by various enemies ; for ...
... observations which I have made , İ believe that it is the seedlings which suffer most from germinating in ground already thickly stocked with other plants . Seedlings , also , are destroyed in vast numbers by various enemies ; for ...
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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