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 47
... continuous , in which case he can hardly hope to find the intermediate links between his doubtful forms , he will have to trust almost entirely to analogy , and his difficulties rise to a climax . Certainly no clear line of demarcation ...
... continuous , in which case he can hardly hope to find the intermediate links between his doubtful forms , he will have to trust almost entirely to analogy , and his difficulties rise to a climax . Certainly no clear line of demarcation ...
Página 93
... continuous area , the physical conditions at least will generally graduate away insensibly from one district to another . The intercrossing will most affect those animals which unite for each birth , which wander much , and which do not ...
... continuous area , the physical conditions at least will generally graduate away insensibly from one district to another . The intercrossing will most affect those animals which unite for each birth , which wander much , and which do not ...
Página 96
... continuous , owing to oscilla- tions of level , will often have recently existed in a broken condition , so that the good effects of isolation will generally , to a certain extent , have concurred . Finally , I conclude that , although ...
... continuous , owing to oscilla- tions of level , will often have recently existed in a broken condition , so that the good effects of isolation will generally , to a certain extent , have concurred . Finally , I conclude that , although ...
Página 156
... continuous , that it has been continuous during a long period . Geology 156 ON THE ORIGIN OF SPECIES.
... continuous , that it has been continuous during a long period . Geology 156 ON THE ORIGIN OF SPECIES.
Página 157
... continuous must often have existed within recent times in a far less continuous and uniform condition than at present . But I will pass over this way of escaping from the difficulty ; for I believe that many perfectly defined species ...
... continuous must often have existed within recent times in a far less continuous and uniform condition than at present . But I will pass over this way of escaping from the difficulty ; for I believe that many perfectly defined species ...
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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