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
... perfect as we now see them ; but this assumption seems to me to be no explanation , for it leaves the case of the coadaptations of organic beings to each other and to their physical conditions of life , untouched and unexplained . ( It ...
... perfect as we now see them ; but this assumption seems to me to be no explanation , for it leaves the case of the coadaptations of organic beings to each other and to their physical conditions of life , untouched and unexplained . ( It ...
Página 14
... 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 ...
... 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 15
... perfect fertility of varieties when crossed , ―a subject hereafter to be discussed ) , domestic races of the same species differ from each other in the same manner as , only in most cases in a lesser degree than , do closely - allied ...
... perfect fertility of varieties when crossed , ―a subject hereafter to be discussed ) , domestic races of the same species differ from each other in the same manner as , only in most cases in a lesser degree than , do closely - allied ...
Página 21
... perfect plumage is acquired varies , as does the state of the down with which the nestling birds are clothed when hatched . The shape and size of the eggs vary . The manner of flight differs remarkably ; as does in some breeds the voice ...
... perfect plumage is acquired varies , as does the state of the down with which the nestling birds are clothed when hatched . The shape and size of the eggs vary . The manner of flight differs remarkably ; as does in some breeds the voice ...
Página 25
... perfect series between the extremes of structure . Thirdly , those characters which are mainly distinctive of each breed , for instance the wattle and length of beak of the carrier , the shortness of that of the tumbler , and the number ...
... perfect series between the extremes of structure . Thirdly , those characters which are mainly distinctive of each breed , for instance the wattle and length of beak of the carrier , the shortness of that of the tumbler , and the number ...
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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