The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432 páginas |
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Página 16
... slight degree in each other . Altogether at least a score of pigeons might be chosen , which , if shown to an ornithologist , and he were told that they were wild birds , would certainly be ranked by him as well - defined species ...
... slight degree in each other . Altogether at least a score of pigeons might be chosen , which , if shown to an ornithologist , and he were told that they were wild birds , would certainly be ranked by him as well - defined species ...
Página 20
... slight differences , yet they ignore all general arguments , and refuse to sum up in their minds slight differences accumulated during many successive generations . May not those naturalists who , knowing far less of the laws of ...
... slight differences , yet they ignore all general arguments , and refuse to sum up in their minds slight differences accumulated during many successive generations . May not those naturalists who , knowing far less of the laws of ...
Página 23
... slight differences . It is not that the varieties which differ largely in some one point do not differ at all in other points ; this is hardly ever , -I speak after careful observation , -perhaps never , the case . The law of correlated ...
... slight differences . It is not that the varieties which differ largely in some one point do not differ at all in other points ; this is hardly ever , -I speak after careful observation , -perhaps never , the case . The law of correlated ...
Página 26
... slight in internal parts or organs . Man can hardly select , or only with much difficulty , any deviation of ... slight degree by nature . No man would ever try to make a fantail till he saw a pigeon with a tail developed in some slight ...
... slight in internal parts or organs . Man can hardly select , or only with much difficulty , any deviation of ... slight degree by nature . No man would ever try to make a fantail till he saw a pigeon with a tail developed in some slight ...
Página 27
... slight , in one's own possession . Nor must the value which would formerly have been set on any slight differences in the individuals of the same species , be judged of by the value which is now set on them , after several breeds have ...
... slight , in one's own possession . Nor must the value which would formerly have been set on any slight differences in the individuals of the same species , be judged of by the value which is now set on them , after several breeds have ...
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Términos y frases comunes
accumulated adapted admit affinities allied species America analogous ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids important increase individuals inhabitants inherited insects instance instincts intercrossing intermediate kind lamellæ larvæ less living male mammals manner Marsupials migration modified descendants natural selection naturalists nearly nest occasionally occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds sexual selection Silurian slight South America stamens sterility structure successive supposed tend theory tion variability variations varieties vary whilst whole wings young