On the Origin of Species by Means of Natural Selection: Or, The Preservation of Favoured Races in the Struggle for LifeEaston Press, 1976 - 470 páginas |
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Página 2
... manner . It is extremely difficult to come to any conclusion in regard to the extent of the changes which have been thus definitely induced . There can , however , be little doubt about many slight changes , such as size from the amount ...
... manner . It is extremely difficult to come to any conclusion in regard to the extent of the changes which have been thus definitely induced . There can , however , be little doubt about many slight changes , such as size from the amount ...
Página 120
... manner in comparison with the other species of the same genus . The rule applies very strongly in the case of secondary sexual characters , when displayed in any unusual manner . The term , secondary sexual characters , used by Hunter ...
... manner in comparison with the other species of the same genus . The rule applies very strongly in the case of secondary sexual characters , when displayed in any unusual manner . The term , secondary sexual characters , used by Hunter ...
Página 208
... manner . That many species have been evolved in an extremely gradual manner , there can hardly be a doubt . The species and even the genera of many large natural families are so closely allied together , that it is difficult to ...
... manner . That many species have been evolved in an extremely gradual manner , there can hardly be a doubt . The species and even the genera of many large natural families are so closely allied together , that it is difficult to ...
Contenido
VARIATION UNDER NATURE | 30 |
STRUGGLE FOR EXISTENCE | 45 |
NATURAL SELECTION | 59 |
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Términos y frases comunes
accumulated adapted admit affinities allied species America ancient appear beak become bees believe belonging birds breeds cause cells characters climate closely allied colour common progenitor continuous crossed crustaceans degree developed difficulty distinct species divergence doubt effects eggs embryo existing exterminated extinct extremely facts favourable fertilised fertility flowers formation forms fossil Fritz Müller genera genus geological geological period gradations greater number groups of species habits Hence hybrids hybrids produced 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 offspring organisation organs Origin of Species parent peculiar perfect pigeons pistil plants pollen present preserved principle probably produced quadrupeds ranked reciprocal crosses remarked resemblance rudimentary seeds slight South America stamens sterility structure struggle successive supposed swimbladder theory variability variations varieties vary whilst whole wings young