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 29
... variability , both by acting directly on the organisation , and indirectly by affecting the reproductive system . It is not probable that variability is an inherent and necessary contingent , under all circumstances . The greater or ...
... variability , both by acting directly on the organisation , and indirectly by affecting the reproductive system . It is not probable that variability is an inherent and necessary contingent , under all circumstances . The greater or ...
Página 122
... variability in the parts undergoing modification may always be expected . Now let us turn to nature . When a part ... variability , which has continually been accumulated by natural selection for the benefit of the species . But as the ...
... variability in the parts undergoing modification may always be expected . Now let us turn to nature . When a part ... variability , which has continually been accumulated by natural selection for the benefit of the species . But as the ...
Página 125
... variability of any part which is developed in a species in an extraordinary manner in comparison with the same part in its congeners ; and the slight degree of variability in a part , however extraordinarily it may be developed , if it ...
... variability of any part which is developed in a species in an extraordinary manner in comparison with the same part in its congeners ; and the slight degree of variability in a part , however extraordinarily it may be developed , if it ...
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