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 16
... existing domesticated pro- ductions have varied . In the case of most of our anciently domesticated animals and plants , I do not think it is possible to come to any definite conclusion , whether they have descended from one or several ...
... existing domesticated pro- ductions have varied . In the case of most of our anciently domesticated animals and plants , I do not think it is possible to come to any definite conclusion , whether they have descended from one or several ...
Página 17
... existing . Even if this latter fact were found more strictly and generally true than seems to me to be the case , what does it show , but that some of our breeds originated there , four or five thousand years ago ? But Mr. Horner's ...
... existing . Even if this latter fact were found more strictly and generally true than seems to me to be the case , what does it show , but that some of our breeds originated there , four or five thousand years ago ? But Mr. Horner's ...
Página 24
... existing species is thus coloured and marked , so that in each separate breed there might be a tendency to revert to the very same colours and markings . Or , secondly , that each breed , even the purest , has within a dozen or , at ...
... existing species is thus coloured and marked , so that in each separate breed there might be a tendency to revert to the very same colours and markings . Or , secondly , that each breed , even the purest , has within a dozen or , at ...
Página 32
... existing in the country . But , for our purpose , a kind of Selection , which may be called Unconscious , and which results from every one trying to possess and breed from the best individual animals , is more im- portant . Thus , a man ...
... existing in the country . But , for our purpose , a kind of Selection , which may be called Unconscious , and which results from every one trying to possess and breed from the best individual animals , is more im- portant . Thus , a man ...
Página 33
... existing in Britain , India , and Persia , we can , I think , clearly trace the stages through which they have insensibly passed , and come to differ so greatly from the rock - pigeon . Youatt gives an excellent illustration of the ...
... existing in Britain , India , and Persia , we can , I think , clearly trace the stages through which they have insensibly passed , and come to differ so greatly from the rock - pigeon . Youatt gives an excellent illustration of the ...
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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