The Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeCollier Books, 1962 - 512 páginas |
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Página 165
... laws of variation is pro- found . Not in one case out of a hundred can we pretend to assign any reason why this or that part has varied . But when- ever we have the means of instituting a comparison , the same laws appear to have acted ...
... laws of variation is pro- found . Not in one case out of a hundred can we pretend to assign any reason why this or that part has varied . But when- ever we have the means of instituting a comparison , the same laws appear to have acted ...
Página 282
... Laws Governing the Sterility of First Crosses and of Hybrids We will now consider a little more in detail the laws gov- erning the sterility of first crosses and of hybrids . Our chief object will be to see whether or not these laws ...
... Laws Governing the Sterility of First Crosses and of Hybrids We will now consider a little more in detail the laws gov- erning the sterility of first crosses and of hybrids . Our chief object will be to see whether or not these laws ...
Página 413
... laws of life throughout time and space ; the laws governing the succession of forms in past times being nearly the same with those governing at the present time the differences in different areas . We see this in many facts . The ...
... laws of life throughout time and space ; the laws governing the succession of forms in past times being nearly the same with those governing at the present time the differences in different areas . We see this in many facts . The ...
Contenido
An Historical Sketch | 15 |
Introduction | 25 |
Variation Under Nature | 58 |
Derechos de autor | |
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Otras ediciones - Ver todas
The Origin of Species by Means of Natural Selection: Or, The ..., Volumen2 Charles Darwin Vista de fragmentos - 1972 |
The Origin of Species by Means of Natural Selection: Or, The Preservation of ... Charles Darwin Vista de fragmentos - 1962 |
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 common continent crossed crustaceans degree developed difficulty distinct species domestic doubt eggs embryo existing extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological Glacial period gradations greater number groups of species habits Hence hybrids important 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 offspring organisation organs Origin of Species parent peculiar perfect pigeons pistil pollen present principle probably produced progenitor 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