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 43
... remarked in regard to plants , and Westwood in regard to insects , that in large genera the amount of difference between the species is often exceedingly small . I have endeavoured to test this numerically by averages , and , as far as ...
... remarked in regard to plants , and Westwood in regard to insects , that in large genera the amount of difference between the species is often exceedingly small . I have endeavoured to test this numerically by averages , and , as far as ...
Página 329
... remarked , the most important of all relations . Thus the high importance of barriers comes into play by checking migration ; as does time for the slow process of modification through natural selection . Widely - ranging species ...
... remarked , the most important of all relations . Thus the high importance of barriers comes into play by checking migration ; as does time for the slow process of modification through natural selection . Widely - ranging species ...
Página 441
... remarked , " the spores and other reproductive bodies of many of the lower alga may claim to have first a characteristically animal , and then an unequivocally vegetable existence . " Therefore , on the principle of natural selection ...
... remarked , " the spores and other reproductive bodies of many of the lower alga may claim to have first a characteristically animal , and then an unequivocally vegetable existence . " Therefore , on the principle of natural selection ...
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