Search Results - The Complete Work of Charles Darwin Online

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

scales were scattered over the surface of the wing, but gradually they concentrated themselves, and formed broad, velvety bands, or strong, prominent brushes, and they attained their highest pitch of evolution when they became enclosed within pits or folds of the skin, which could be opened to let the delicious fragrance stream forth suddenly towards the female. Thus in this case also we see that characters, the original use of which was to bring the sexes together, and so to maintain the species

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

useless. On the other hand, he strongly combated the belief, that great changes would be necessary to explain the origin of species. Some authors had propounded the idea that highly adapted organs, e.g. the wings of a bird, could not have been developed in any other way than by a comparatively sudden modification of a well defined and important kind. Such a conception would allow of great breaks or discontinuity in the evolution of highly differentiated animals and plants, shortening the time

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

guessed at by him. But in our endeavour to arrive at a true conception of his view I think that the chapter on Pangenesis should be our leading guide, and that we should try to interpret the more difficult passages by that chapter. A careful and often repeated study of the Pangenesis hypothesis has convinced me that Darwin, when he wrote that chapter, was well aware that ordinary variability has nothing to do with evolution, but that other kinds of variation were necessary. In some chapters he comes

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

condition was in the main the result of Selection, with disuse aiding, and in another place that the main cause of degeneration was disuse, but that Selection had aided. To Darwin however I think the point would have seemed one of dialectics merely. To him the one paramount purpose was to show that somehow an Evolution by means of Variation and Heredity might have brought about the facts observed, and whether they had come to pass in the one way or the other was a matter of subordinate concern

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

hypotheses have been formulated on these lines, with special reference to the evolution of man. Pithecanthropus is regarded by some authorities as the direct ancestor of man, by others as a side-track failure in the attempt at the evolution of man. The problem of the monophyletic or polyphyletic origin of the human race has also been much discussed. Sergi2 inclines towards the assumption of a polyphyletic origin of the three main races of man, the African primitive form of which has given rise

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

memorable Congress I had undertaken to deliver the first address (September 18th) on the subject of Modern evolution in relation to the whole of science. I maintained that Darwin's theory not only solved the great problem of the origin of species, but that its implications, especially in regard to the nature of man, threw considerable light on the whole of science, and on anthropology in particular. The discovery of the real origin of man by evolution from a long series of mammal ancestors threw light

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

the modern State. He spoke of the theory of evolution as an unproved hypothesis, and declared that it ought not to be taught in the schools, because it was dangerous to the State. We must not, he said, teach that man has descended from the ape or any other animal. When Darwin, usually so lenient in his judgment, read the English translation of Virchow's speech, he expressed his disapproval in strong terms. But the great authority that Virchow had—an authority well founded in pathology and

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

is negative. The recapitulation theory originated as a deduction from the evolution theory and as a deduction it still remains. Let us before leaving the subject apply another test. If the evolution theory and the recapitulation theory are both true, how is it that living birds are not only without teeth but have no rudiments of teeth at any stage of their existence? How is it that the missing digits in birds and mammals, the missing or reduced limb of snakes and whales, the reduced mandibulo

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

-history has, with the progress of evolution, become longer and more complicated. Now there can be no doubt that the life-history of organisms has been shortened in the way above suggested, for cases are known in which this can practically be seen to occur at the present day. But the process of lengthening by the creation of new stages at the other end of the life-cycle is more difficult to conceive and moreover there is no evidence for its having occurred. This, indeed, may have occurred, as is

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

least as long as it is at the present time. The qualification implied by the words in italics is necessary, for it is clearly possible that the external conditions then existing were not suitable for the production of all the stages of the potential life-history, and that what we call organic evolution has consisted in a gradual evolution of new environments to which the organism's innate capacity of change has enabled it to adapt itself. We have warrant for this possibility in the case of the

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

believing, the Angiosperms came from a type with a flower resembling in its complexity that of Mesozoic Cycads, almost the whole evolution of the flower in the highest plants has been a process of reduction. The stamen, in particular, has undoubtedly become extremely simplified during evolution; in the most primitive known seed-plants it was a highly compound leaf or pinna; its reduction has gone on in the Conifers and modern Cycads, as well as in the Angiosperms, though in different ways and to a

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

passage through which the pollen entered; the open neck of the pollen-chamber protruded through the micropyle and itself received the pollen. We have met with an analogous case, at a more advanced stage of evolution, in the Bennettiteae (p. 208), where the wall of the gynaecium, though otherwise closed, did not provide a stigma to catch the pollen, but allowed the micropyles of the ovules to protrude and receive the pollen in the old gymnospermous fashion. The integument in the one case and the

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

men will drag after them those naturalists who have too firmly fixed in their heads that a species is an entity2. Mimicry was not only one of the first great departments of zoological knowledge to be studied under the inspiration of Natural Selection, it is still and will always remain one of the most interesting and important of subjects in relation to this theory as well as to evolution. In mimicry we investigate the effect of environment in its simplest form: we trace the effects of the

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

this predominance. Thus if the female appear in two different forms and the male in only one it will be twice as probable that she will happen to possess a sufficient foundation for the evolution of mimicry. (3) The appearance of melanic or partially melanic forms in the female has been of very great service, providing as it does a change of ground-colour. Thus the mimicry of the black generally red-marked American Aristolochia swallowtails (Pharmacophagus) by the females of Papilio swallowtails

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

is in itself an indication that the dispersing agencies avail themselves in a hap-hazard fashion of characters and capacities that have been developed in other connections2. Their utility in these respects is an accident in the plant's life3. He attributes this utility to a determining agency, an influence which constantly reappears in various shapes in the literature of Evolution and is ultra-scientific in the sense that it bars the way to the search for material causes. He goes so far as to

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

degree of development as those now existing. The fact was commented upon by Hooker2, but its full significance seems to have been scarcely appreciated. For it implied not merely that their evolution must have taken place but the foundations of existing distribution must have been laid in a preceding age. We now know from the discoveries of the last fifty years that the remains of the Neocomian flora occur over an area extending through 30 of latitude. The conclusion is irresistible that within this

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

biological evolution and psychological evolution is to be sought,—as Darwin fully realised,—in the phenomena of instinct, broadly considered. The term instinctive has also a psychological connotation. What is that connotation? Let us take the case of the swimming duckling or the pecking chick, and fix our attention on the first instinctive performance. Grant that just as there is, strictly speaking, no inherited behaviour, but only the conditions which render such behaviour under appropriate

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

summon to the task. It can only be dealt with here from a special point of view—that which may serve to illustrate the influence of certain mental factors on the course of evolution. From this point of view too much stress can scarcely be laid on the dominance of emotion during the period of courtship and pairing in the more highly organised animals. It is a period of maximum vigour, maximum activity, and, correlated with special modes of behaviour and special organic and visceral accompaniments

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

those which stand lower in the scale of mental evolution, but that they have an equally large or perhaps larger mass of instinctive raw material which may furnish the stuff to be elaborated by intelligent processes. There is, perhaps, a greater abundance of the primary tissue of experience to be refashioned and integrated by secondary modification; there is probably the same differentiation in relation to the determining biological ends, but there is at the outset less differentiation of the

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A162 Book: Seward, A. C. ed. 1909. Darwin and modern science. Essays in commemoration of the centenary of the birth of Charles Darwin and of the fiftieth anniversary of the publication of The origin of species. Cambridge: Cambridge University Press. Text Image PDF

advance than on the fact of their underlying community of nature. The conceptual intelligence which is especially characteristic of the higher mental procedure of man is more firmly distinguished from the perceptual intelligence which he shares with the lower animals—distinguished now as a higher product of evolution, no longer as differing in origin or different in kind. Some progress has been made, on the one hand in rendering an account of intelligent profiting by experience under the