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 8
... breed freely under confinement , even in the many cases when the male and female unite . How many animals there are which will not breed , though living long under not very close con- finement in their native country ! This is generally ...
... breed freely under confinement , even in the many cases when the male and female unite . How many animals there are which will not breed , though living long under not very close con- finement in their native country ! This is generally ...
Página 9
... breed freely under the most unnatural conditions ( for instance , the rabbit and ferret kept in hutches ) , showing that their repro- ductive system has not been thus affected ; so will some animals and plants withstand domestication or ...
... breed freely under the most unnatural conditions ( for instance , the rabbit and ferret kept in hutches ) , showing that their repro- ductive system has not been thus affected ; so will some animals and plants withstand domestication or ...
Página 11
... Breeders believe that long limbs are almost always accompanied by an elongated head . Some instances of correlation are quite whimsical : thus cats with blue eyes are invariably deaf ; colour and constitutional peculiarities go together ...
... Breeders believe that long limbs are almost always accompanied by an elongated head . Some instances of correlation are quite whimsical : thus cats with blue eyes are invariably deaf ; colour and constitutional peculiarities go together ...
Página 13
... breeds are often trans- mitted either exclusively , or in a much greater degree , to males alone . A much more important rule , which I think may be trusted , is that , at whatever period of life a peculiarity appears , it tends to ...
... breeds are often trans- mitted either exclusively , or in a much greater degree , to males alone . A much more important rule , which I think may be trusted , is that , at whatever period of life a peculiarity appears , it tends to ...
Página 14
... breed our cart and race horses , long and short horned cattle , and poultry of various breeds , and esculent vegetables , for an almost infinite number of generations , would be opposed to all experience . I may add , that when under ...
... breed our cart and race horses , long and short horned cattle , and poultry of various breeds , and esculent vegetables , for an almost infinite number of generations , would be opposed to all experience . I may add , that when under ...
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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