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 1
... nearly finished ; but as it will take me two or three more years to complete it , and as my health is far from strong , I have been urged to publish this Abstract . I have more especially been induced to do this , as Mr. Wallace , who ...
... nearly finished ; but as it will take me two or three more years to complete it , and as my health is far from strong , I have been urged to publish this Abstract . I have more especially been induced to do this , as Mr. Wallace , who ...
Página 10
... nearly all the individuals exposed to certain conditions are affected in the same way , the change at first appears to be directly due to such conditions ; but in some cases it can be shown that quite opposite conditions produce similar ...
... nearly all the individuals exposed to certain conditions are affected in the same way , the change at first appears to be directly due to such conditions ; but in some cases it can be shown that quite opposite conditions produce similar ...
Página 13
... nearly mature ; peculiarities in the silkworm are known to appear at the corresponding caterpillar or cocoon stage . But hereditary diseases and some other facts make me believe that the rule has a wider extension , and that when there ...
... nearly mature ; peculiarities in the silkworm are known to appear at the corresponding caterpillar or cocoon stage . But hereditary diseases and some other facts make me believe that the rule has a wider extension , and that when there ...
Página 14
... nearly perfect reversion had ensued . It would be quite necessary , in order to prevent the effects of inter- crossing , that only a single variety should be turned loose in its new home . Nevertheless , as our varieties certainly do ...
... nearly perfect reversion had ensued . It would be quite necessary , in order to prevent the effects of inter- crossing , that only a single variety should be turned loose in its new home . Nevertheless , as our varieties certainly do ...
Página 19
... nearly intermediate between two extremely different races or species , I can hardly believe . Sir J. Sebright ex- pressly experimentised for this object , and failed . The offspring from the first cross between two pure breeds is ...
... nearly intermediate between two extremely different races or species , I can hardly believe . Sir J. Sebright ex- pressly experimentised for this object , and failed . The offspring from the first cross between two pure breeds is ...
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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