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 69
... individual differences , and this led me fully to discuss the results of unconscious selection by man , which depends on the preservation of all the more or less valuable individuals , and on the destruction of the worst . I saw , also ...
... individual differences , and this led me fully to discuss the results of unconscious selection by man , which depends on the preservation of all the more or less valuable individuals , and on the destruction of the worst . I saw , also ...
Página 77
... individual , can be shown to be physically impossible . Cirripedes long appeared to me to present , under this point of view , a case of great difficulty ; but I have been enabled , by a fortunate chance , to prove that two individuals ...
... individual , can be shown to be physically impossible . Cirripedes long appeared to me to present , under this point of view , a case of great difficulty ; but I have been enabled , by a fortunate chance , to prove that two individuals ...
Página 182
... individuals , as with the race - horse and greyhound , or as with the game - cock , by breeding from the victorious birds . So under nature with the nascent giraffe the individuals which were the highest browsers , and were able during ...
... individuals , as with the race - horse and greyhound , or as with the game - cock , by breeding from the victorious birds . So under nature with the nascent giraffe the individuals which were the highest browsers , and were able during ...
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