Life on the Earth: Its Origin and SuccessionMacmillan and Company, 1860 - 224 стор. |
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Результати 1-5 із 18
Сторінка 14
... thickness of each zone in fathoms . The fourth the number of species found in each zone . The fifth is a column which I have calculated by dividing the fourth by the third , to shew the relative productiveness of each zone . ( For the ...
... thickness of each zone in fathoms . The fourth the number of species found in each zone . The fifth is a column which I have calculated by dividing the fourth by the third , to shew the relative productiveness of each zone . ( For the ...
Сторінка 52
... thickness of the Fossil- iferous strata , down to the Lingula beds of Wales , is assumed to be 10 miles , 52800 ft . That is not the maximum thickness , which in Britain is supposed by Ramsay to be 72584 ft . In his estimate the Palæ ...
... thickness of the Fossil- iferous strata , down to the Lingula beds of Wales , is assumed to be 10 miles , 52800 ft . That is not the maximum thickness , which in Britain is supposed by Ramsay to be 72584 ft . In his estimate the Palæ ...
Сторінка 60
... thickness of the deposits - which represents elapsed time - is taken into account , the variety of forms in a given thickness or given period of time is very much less . For if we take account of the thickness according to the maximum ...
... thickness of the deposits - which represents elapsed time - is taken into account , the variety of forms in a given thickness or given period of time is very much less . For if we take account of the thickness according to the maximum ...
Сторінка 61
... thicknesses in each of these systems of strata . Accord- ing to Morris's estimates of thickness ( p . 52 ) , the relative numbers would have been 432 , 251 , 59 . Had we instead of the figures which represent the thicknesses and number ...
... thicknesses in each of these systems of strata . Accord- ing to Morris's estimates of thickness ( p . 52 ) , the relative numbers would have been 432 , 251 , 59 . Had we instead of the figures which represent the thicknesses and number ...
Сторінка 64
... thicknesses . This richness ( expressed by numbers on the right side ) rises from almost zero in the Lingula beds to a maximum in the upper part of the Wenlock series , and dies out almost to zero in the beds of Passage to the Old Red ...
... thicknesses . This richness ( expressed by numbers on the right side ) rises from almost zero in the Lingula beds to a maximum in the upper part of the Wenlock series , and dies out almost to zero in the beds of Passage to the Old Red ...
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Загальні терміни та фрази
abundance affinity ages Ammonites Amorphozoa ancient Annelida antiquity appear atmosphere beds Brachiopoda British Carbon Carboniferous Cenozoic Cenozoic Strata Cephalopoda Cetacea Chalk character classes climate Coal creation Cretaceous Crocodilia Crustacea deposits Devonian Dimyaria distribution earlier earliest earth Echinodermata effect Eocene epoch equal examples existing favourable Fishes forms fossil freshwater Gasteropoda genera genus geological geological periods globe Goniatites groups heat hypothesis idea Insects Invertebrata land Lias limestone limited Lingula living Llandeilo Lower Palæozoic Mammalia marine mean temperature Mesozoic Mesozoic Period modern Oceans Mollusca Monomyaria naturalists nature number of species occur Oolitic organic origin Palæontology Paleozoic Strata perhaps Permian phenomena plants and animals Pleiocene Polyzoa prevalent races radiation recent regard remarkable represented Reptiles rivers rocks sediments shale shells shew Silurian Stonesfield structure succession suppose surface Teleosaurus Tertiary Strata thickness tion traced Uniformitarian Upper variations variety vegetable Vertebrata whole zone Zoophyta دو
Популярні уривки
Сторінка 194 - As all the living forms of life are the lineal descendants of those which lived long before the Cambrian epoch, we may feel certain that the ordinary succession by generation has never once been broken, and that no cataclysm has desolated the whole world.
Сторінка 195 - There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into a few forms or into one; and that, whilst this planet has gone cycling on according to the fixed law of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being evolved.
Сторінка 194 - Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth, have descended from some one primordial form, into which life was first breathed.
Сторінка 193 - I formerly entertained, namely, that each species has been independently created, is erroneous. I am fully convinced that species are not immutable; but that those belonging to what are called the same genera are lineal descendants of some other and generally extinct species, in the same manner as the acknowledged varieties of any one species are the descendants of that species. Furthermore, I am convinced that Natural Selection has been the main, but not exclusive, means of modification.
Сторінка 193 - I cannot doubt that the theory of descent with modification embraces all the members of the same great class or kingdom. I believe that animals are descended from at most only four or five progenitors, and plants from an equal or lesser number.
Сторінка 195 - It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth...
Сторінка 194 - Nevertheless all living things have much in common, in their chemical composition, their cellular structure, their laws of growth, and their liability to injurious influences.
Сторінка 178 - The intermixture of distinct species is guarded against by the aversion of the individuals composing them to sexual union, or by the sterility of the mule offspring. It does not appear that true hybrid races have ever been perpetuated for several generations, even by the assistance of man; for the cases usually cited relate to the crossing of mules with individuals of pure species, and not to the intermixture of hybrid with hybrid.
Сторінка 195 - Thus, from the war of nature, from famine and death, the most exalted object which we are capable of conceiving, namely the production of the higher animals, directly follows. There is grandeur in this view of life...
Сторінка 192 - I can entertain no doubt, after the most deliberate study and dispassionate judgment of which I am capable, that the view which most naturalists until recently entertained, and which I formerly entertained, namely, that each species has been independently created, is erroneous. I am fully convinced that species are not immutable...