The Origin of Species by Means of Natural Selection,: Or the Preservation of Favoured Races in the Struggle for LifeJohn Murray, Albemarle Street., 1891 - 432 páginas |
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Página 268
... Silurian trilobites are descended from some one crustacean , which must have lived long before the Cambrian age , and which probably differed greatly from any known animal . Some of the most ancient animals , as the Nautilus , Lingula ...
... Silurian trilobites are descended from some one crustacean , which must have lived long before the Cambrian age , and which probably differed greatly from any known animal . Some of the most ancient animals , as the Nautilus , Lingula ...
Página 272
... Silurian Lingula differs but little from the living species of this genus ; whereas most of the other Silurian Molluscs and all the Crustaceans have changed greatly . The productions of the land seem to have changed at a quicker rate ...
... Silurian Lingula differs but little from the living species of this genus ; whereas most of the other Silurian Molluscs and all the Crustaceans have changed greatly . The productions of the land seem to have changed at a quicker rate ...
Página 274
... ages must have been connected by an unbroken series of generations , from the lowest Silurian stratum to the present day . We have seen in the last chapter that whole groups. 274 [ CHAP . XI . THE GEOLOGICAL SUCCESSION.
... ages must have been connected by an unbroken series of generations , from the lowest Silurian stratum to the present day . We have seen in the last chapter that whole groups. 274 [ CHAP . XI . THE GEOLOGICAL SUCCESSION.
Página 282
... Silurian deposits of Bohemia and Scandinavia ; nevertheless he finds a surprising amount of difference in the species . If the several formations in these regions have not been deposited during the same exact periods , -a forma- tion in ...
... Silurian deposits of Bohemia and Scandinavia ; nevertheless he finds a surprising amount of difference in the species . If the several formations in these regions have not been deposited during the same exact periods , -a forma- tion in ...
Página 287
... Silurian systems . But each fauna is not necessarily exactly intermediate , as unequal intervals of time have elapsed between consecutive formations . It is no real objection to the truth of the statement that the fauna of each period ...
... Silurian systems . But each fauna is not necessarily exactly intermediate , as unequal intervals of time have elapsed between consecutive formations . It is no real objection to the truth of the statement that the fauna of each period ...
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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 continued crossed crustaceans degree developed difficulty distinct species domestic animals doubt effects eggs embryo existing extinct extremely facts favourable female fertilised fertility flowers formation formerly forms fossil Fritz Müller genera genus geological geological period Glacial period gradations greater number habits Hence hybrids 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 occur oceanic islands offspring organisation organs parent peculiar perfect pigeon pistil pollen present preserved principle probably produced 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