A Primer of Darwinism and Organic Evolution |
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Page 37
... head , at the same time diminishing the strength of its bones and of the muscles of the neck , as may readily be gathered from the figure on the next page . So far has the shortening process gone , that , while the proportion of the ...
... head , at the same time diminishing the strength of its bones and of the muscles of the neck , as may readily be gathered from the figure on the next page . So far has the shortening process gone , that , while the proportion of the ...
Page 38
Joseph Young Bergen, Fanny Dickerson Bergen. FIG . 3.- - Head of Wild Boar , and of " Golden Days , " a pig of the Yorkshire Large Breed . Fig . 4. Axolotl . Fig . 5. Amblystoma . 388 THE DEVELOPMENT THEORY .
Joseph Young Bergen, Fanny Dickerson Bergen. FIG . 3.- - Head of Wild Boar , and of " Golden Days , " a pig of the Yorkshire Large Breed . Fig . 4. Axolotl . Fig . 5. Amblystoma . 388 THE DEVELOPMENT THEORY .
Page 54
... head of sudden and unexplained changes , due , possibly , to some kind of pre - natal influence . Melanism , or the presence of too much color- ing - matter , the exact opposite of albinism , is , like it , a condition occurring both ...
... head of sudden and unexplained changes , due , possibly , to some kind of pre - natal influence . Melanism , or the presence of too much color- ing - matter , the exact opposite of albinism , is , like it , a condition occurring both ...
Page 86
... head of the puff - adder , which is perfectly harmless , but looks , when it raises itself to strike , not a little like one of the poisonous snakes , is probably another case of mimicry for the sake of protection . So , too , there are ...
... head of the puff - adder , which is perfectly harmless , but looks , when it raises itself to strike , not a little like one of the poisonous snakes , is probably another case of mimicry for the sake of protection . So , too , there are ...
Page 88
... heads . There are , however , some phenomena mani- fested by plants , which have an important bear- ing on the development theory , and which may best be stated in this connection . Darwin 1 and Wallace 2 have called the attention of ...
... heads . There are , however , some phenomena mani- fested by plants , which have an important bear- ing on the development theory , and which may best be stated in this connection . Darwin 1 and Wallace 2 have called the attention of ...
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A Primer of Darwinism and Organic Evolution Joseph Young Bergen,Fanny Dickerson Bergen No preview available - 2015 |
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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.