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 75
... modifying and improving some of the varying inhabitants . as all the inhabitants of each country are struggling together with nicely balanced forces , extremely slight modifications in the structure or habits of one in- habitant would ...
... modifying and improving some of the varying inhabitants . as all the inhabitants of each country are struggling together with nicely balanced forces , extremely slight modifications in the structure or habits of one in- habitant would ...
Página 78
... modifications , often of the most unexpected nature . As we see that those variations which under domesti- cation ... modify organic beings at any age , by the accumulation of variations profitable at that age , and by their inheritance ...
... modifications , often of the most unexpected nature . As we see that those variations which under domesti- cation ... modify organic beings at any age , by the accumulation of variations profitable at that age , and by their inheritance ...
Página 79
... modifications in the adult will probably often affect the structure of the larva ; but in all cases natural selection ... modification would be very slow , and there would be simultaneously the most rigorous selection of the young birds ...
... modifications in the adult will probably often affect the structure of the larva ; but in all cases natural selection ... modification would be very slow , and there would be simultaneously the most rigorous selection of the young birds ...
Página 87
... modification in their structure . This We On the Intercrossing of Individuals . —I must here introduce a short digression . In the case of animals and plants with separated sexes , it is of course obvious that two individuals must ...
... modification in their structure . This We On the Intercrossing of Individuals . —I must here introduce a short digression . In the case of animals and plants with separated sexes , it is of course obvious that two individuals must ...
Página 93
... modification surely but slowly follow from this unconscious process of selection , notwithstanding a large amount of ... modifying and improving a species in the several districts , there will be inter- crossing with the other ...
... modification surely but slowly follow from this unconscious process of selection , notwithstanding a large amount of ... modifying and improving a species in the several districts , there will be inter- crossing with the other ...
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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