A Primer of Darwinism and Organic Evolution |
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Page 25
... conditions for its growth , and Series II . with unfavorable conditions . Each of the four family - trees here presented is shorn of all its minor twigs and branches , 1 From a plate kindly loaned the authors by Professor Alpheus Hyatt ...
... conditions for its growth , and Series II . with unfavorable conditions . Each of the four family - trees here presented is shorn of all its minor twigs and branches , 1 From a plate kindly loaned the authors by Professor Alpheus Hyatt ...
Page 28
... conditions , were found to vary , not merely from one species into another , but from one genus into another . The question as to whether the time or the manner of beginning of any new species has ever been discovered , asked at the ...
... conditions , were found to vary , not merely from one species into another , but from one genus into another . The question as to whether the time or the manner of beginning of any new species has ever been discovered , asked at the ...
Page 31
... conditions of life as different as can well be conceived , and , on the other hand , of dissimilar varieties being produced under apparently the same external conditions . " 1 Lengthening or shortening the period of life . before birth ...
... conditions of life as different as can well be conceived , and , on the other hand , of dissimilar varieties being produced under apparently the same external conditions . " 1 Lengthening or shortening the period of life . before birth ...
Page 34
... conditions of life are changed . The cats of Mombas , on the East African coast , are covered with short , stiff hair , instead of the usual fur ; and it is related that common cat taken to Mombas , after only eight weeks ' residence ...
... conditions of life are changed . The cats of Mombas , on the East African coast , are covered with short , stiff hair , instead of the usual fur ; and it is related that common cat taken to Mombas , after only eight weeks ' residence ...
Page 40
... - life on the theory of descent , see Professor A. S. Packard's Cave Fauna of N. A. , Mem . Nat'l Acad . Sci . , vol . iv . , pp . 137-143 . perfect condition . It is to this cause that most 40 THE DEVELOPMENT THEORY .
... - life on the theory of descent , see Professor A. S. Packard's Cave Fauna of N. A. , Mem . Nat'l Acad . Sci . , vol . iv . , pp . 137-143 . perfect condition . It is to this cause that most 40 THE DEVELOPMENT THEORY .
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A Primer of Darwinism and Organic Evolution Joseph Young Bergen,Fanny Dickerson Bergen No preview available - 2015 |
Common terms and phrases
abundant algæ America ammonites ancestors animal or plant animals animals and plants apes argillite axolotl become birds body brain breed carboniferous cause cell changes chapter color common condition continent Darwin Delaware Bay deposits development theory dicotyledons domestic earth eggs embryo eozoic Europe evidence example fact fauna feet fishes flint flowering plants foraminifera forms fossil genera genus geological ages gravel groups growth Haeckel horse human hundred Hyatt illustration implements individual insects instance islands kind known latter less life-history living lizards lower animals mals mammals mesozoic natural selection naturalists O. C. Marsh observations organic evolution Origin of Species period pollen present produced Professor quoted rabbits races regard region reptiles resemblance result salamander says seeds sexual shells shown silurian similar skull snails spores Steinheim striking structure sub-kingdom surface teeth tion toes trees variations varieties vegetable vertebrates Wallace wild species zoological
Popular passages
Page 226 - ... would it be too bold to imagine, that all warmblooded animals have arisen from one living filament, which THE GREAT FIRST CAUSE endued with animality, with the power of acquiring new parts, attended with new propensities, directed by irritations, sensations, volitions, and associations; and thus possessing the faculty of continuing to improve by its own inherent activity, and of delivering...
Page 229 - America, and in the geological relations of the present to the past inhabitants of the continent. These facts seemed to throw some light on the origin of species, — that mystery of mysteries, as it has been called by one of our greatest philosophers. On my return home it occurred to me (in 1837) that something might perhaps be made out on this question by patiently accumulating and reflecting on all sorts of facts which could possibly have any bearing on it. After five years I allowed myself to...
Page 58 - Even slow-breeding man has doubled in twenty-five years, and at this rate, in a few thousand years, there would literally not be standing room for his progeny. Linnaeus has calculated that if an annual plant produced only two seeds — and there is no plant so unproductive as this — and their seedlings next year produced two, and so on, then in twenty years there would be a million plants.
Page 58 - ... and during some season or occasional year, otherwise, on the principle of geometrical increase, its numbers would quickly become so inordinately great that no country could support the product.
Page 6 - The tawny lion, pawing to get free His hinder parts, then springs as broke from bonds, And rampant shakes his brinded mane...
Page 28 - On the evidence of palaeontology, the evolution of many existing forms of animal life from their predecessors is no longer an hypothesis, but an historical fact ; it is only the nature of the physiological factors to which that evolution is due which is still open to discussion.
Page 229 - On my return home, it occurred to me — in 1837 — that something might perhaps be made out on this question by patiently accumulating and reflecting on all sorts of facts which could possibly have any bearing on it. After five years' work I allowed myself to speculate on the subject, and drew up some short notes. These I enlarged in 1844 into a sketch of the conclusions which then seemed to me probable. From that period to the present day I have steadily pursued the same object. I hope that I...
Page 183 - ... Not being able to appreciate, or conceive, of the distinction between the psychical phenomena of a chimpanzee and of a Boschisman, or of an Aztec with arrested brain-growth, as being of a nature so essential as to preclude a comparison between them, or as being other than a difference of degree, I cannot shut my eyes to the significance of that all-pervading similitude of structure — every tooth, every bone, strictly homologous — which makes the determination of the difference between Homo...
Page 190 - Further towards the north are to be found men living absolutely in a state of nature, who neither cultivate the ground, nor live in huts ; who neither eat rice nor salt, and who do not associate with each other, but rove about some woods, like wild beasts.
Page 232 - The final cause, of this contest amongst the males seems to be, that the strongest and most active animal should propagate the species, which should thence become improved.