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A1016
Book:
Wallace, A. R. 1880. Island life: or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. London: Macmillan & Co.
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full account of the laws of evolution as affecting distribution, and of the various ocean depths as implying recent or remote union of islands with their adjacent continents; and the result is, that wherever we possess a sufficient knowledge of these various classes of evidence, we find it possible to give a connected and intelligible explanation of all the most striking peculiarities of the organic world. In Madagascar we have undoubtedly one of the most difficult of these problems; but we have
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A1016
Book:
Wallace, A. R. 1880. Island life: or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. London: Macmillan & Co.
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rudiments of wingbones, but also the rudiments of wings, that is, an external limb bearing rigid quills or largely-developed plumes. In the cassowary these wing-feathers are reduced to long spines like porcupine-quills, while even in the Apteryx, the minute external wing bears a series of nearly twenty stiff quill-like feathers.1 These facts render it probable that the struthious birds do not owe their imperfect wings to a direct evolution from a reptilian type, but to a retrograde development from some
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A1016
Book:
Wallace, A. R. 1880. Island life: or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. London: Macmillan & Co.
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of birds. Taking then our British mammals and land-birds, I follow them over the whole area they inhabit, and thus obtain a foundation for the establishment of zoological regions, and a clear insight into their character as distinct from the usual geographical divisions of the globe. The facts thus far established are then shown to be necessary results of the law of evolution. The nature and amount of variation is exhibited by a number of curious examples; the origin, growth, and decay of species
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The Complete Work of Charles Darwin Online [page] 568 Mr. Charles Darwin, in his Origin of Species, very briefly called attention to the fact that his grandfather, Dr. Erasmus Darwin, author of the Botanical Garden and other once-famous books in prose and verse, had proposed a theory of evolution, earlier than Lamarck's, founded on the same principle of spontaneous energy or action from within the organism, selecting among the influences of its environment and making use of them for its own
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established between an animal and its native country, and a new set of problems at once sprang into existence. From the old point of view the diversities of animal life in the separate continents, even where physical conditions were almost identical, was the fact that excited astonishment; but seen by the light of the evolution theory, it is the resemblances rather than the diversities in these distant continents and islands that are most difficult to explain. It thus comes to be admitted that
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most of the disputed questions as to the development of animals, and to confine ourselves to those general principles regulating the origin and development of species and genera which were first laid down by Mr. Darwin twenty years ago, and have now come to be adopted by naturalists as established propositions in the theory of evolution. The Origin of New Species. How, then, do new species arise, supposing the world to have been, physically, much as we now see it; and what becomes of them after
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impossible, and that it either was or must have been effected by means of continents now sunk beneath the ocean. Concluding Remarks. When writing on the subject of distribution it usually seems to have been forgotten that the theory of evolution absolutely necessitates the former existence of a whole series of extinct genera filling up the gap between the isolated genera which in many cases now alone exist; while it is almost an axiom of natural selection that such numerous forms of one type could
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nearest the shore, the finer silt and mud furthest from it. From the earliest geological times the great area of deposit has been as it still is, the marginal belt of sea-floor skirting the land. 1 Geographical Evolution. (Proceedings of the Royal Geographical Society. 1879, p. 426.) [page] 8
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lecture on Geographical Evolution (which was published after the greater part of this chapter had been written) Professor Geikie expresses views in complete accordance with those here advocated. He says: The next long era, the Cretaceous, was more remarkable for slow accumulation of rock under the sea than for the formation of new land. During that time the Atlantic sent its waters across the whole of Europe and into Asia. But they were probably nowhere more than a few hundred feet deep over the
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evolution, nothing can be more certain than that groups now broken up and detached were once continuous, and that fragmentary groups and isolated forms are but the relics of once widespread types, which have been preserved in a few localities where the physical conditions were especially favourable, or where organic competition was less severe. The true explanation of all such remote geographical affinities is, that they date back to a time when the ancestral group of which they are the common
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Linnean Society, 1873, p. 496. On Diversity of Evolution under one set of External Conditions. Proceedings of the Zoological Society of London, 1873, p.80. On the Classification of the Achatinellidæ. [page] 30
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our species, we must certainly hold them to be peculiar till they have been proved to be otherwise. The great speciality of the Irish fishes is very interesting, because it is just what we should expect on the theory of evolution. In Ireland the two main causes of specific change isolation and altered conditions are each more powerful than in Britain. Whatever difficulty continental fishes may have in passing over to Britain, that difficulty will certainly be increased by the second sea
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maritimus, because its only near ally inhabits the coasts of the Mediterranean; and it thus offers an analogous case to the small moth, Elachista rufocinerea, which is found only in Britain and the extreme South of Europe. Looking, then, at what seem to me the probabilities of the case from the standpoint of evolution and natural [page] 33
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presents us with a very large proportion of peculiar species, not only in its mammalia, which have no means of crossing the wide strait which separates it from the mainland, but also in its birds, many of which are quite able to cross over. Here, too, we obtain a glimpse of the way in which species die out and are replaced by others, which quite agrees with what the theory of evolution assures us must have occurred. On a continent, the process of extinction will generally take effect on the
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full account of the laws of evolution as affecting distribution, and of the various ocean depths as implying recent or remote union of islands with their adjacent continents; and the result is, that wherever we possess a sufficient knowledge of these various classes of evidence, we find it possible to give a connected and intelligible explanation of all the most striking peculiarities of the organic world. In Madagascar we have undoubtedly one of the most difficult of these problems; but we have
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rudiments of wingbones, but also the rudiments of wings, that is, an external limb bearing rigid quills or largely-developed plumes. In the cassowary these wing-feathers are reduced to long spines like porcupine-quills, while even in the Apteryx, the minute external wing bears a series of nearly twenty stiff quill-like feathers.1 These facts render it probable that the struthious birds do not owe their imperfect wings to a direct evolution from a reptilian type, but to a retrograde development from some
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of birds. Taking then our British mammals and land-birds, I follow them over the whole area they inhabit, and thus obtain a foundation for the establishment of zoological regions, and a clear insight into their character as distinct from the usual geographical divisions of the globe. The facts thus far established are then shown to be necessary results of the law of evolution. The nature and amount of variation is exhibited by a number of curious examples; the origin, growth, and decay of species
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F913.2
Book:
Darwin, C. R. 1880. De la variation des animaux et des plantes à l'état domestique. Traduit sur la seconde édition anglaise par Ed. Barbier; préface de Carl Vogt. Paris: C. Reinwald et Cie. vol. 2.
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près au même but, tout en offrant de grandes différences dans les phases intermédiaires de leur évolution. Je pourrais citer des cas encore plus frappants relativement aux Echinodermes. Le professeur allemand fait remarquer au sujet des Méduses : « la classification des hydroïdes serait relativement très-simple, si, comme on l'a soutenu à tort, les Méduses identiques générique-ment provenaient toujours de polypes également semblables gé-nériquement; et si, d'autre part, les polypes génériquement
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F913.2
Book:
Darwin, C. R. 1880. De la variation des animaux et des plantes à l'état domestique. Traduit sur la seconde édition anglaise par Ed. Barbier; préface de Carl Vogt. Paris: C. Reinwald et Cie. vol. 2.
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évolution et qui la précède dans l'ordre normal de la croissance. Nous avons prouvé dans la discussion consacrée à ce sujet que la matière formative contenue dans le pollen des plantes, matière qui, en vertu de notre hypothèse, se compose de gemmules, peut s'unir avec les cellules particulièrement développées de la plante mère, et les modifier. Comme les tissus des plantes, autant que nous pouvons le savoir, se forment seulement par la prolifération de cellules préexistantes, nous devons en
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A1016
Book:
Wallace, A. R. 1880. Island life: or, the phenomena and causes of insular faunas and floras, including a revision and attempted solution of the problem of geological climates. London: Macmillan & Co.
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Australian plants in England, 486 Eucalyptus, 179 Eucalyptus and Acacia, why not in New Zealand, 475 Eucalyptus in Eocene of Sheppey, 486 Eupetes, distribution of, 25 Europe, Asia. c., as zoological terms, 31 European birds, range of, 16 European birds in Bermuda, 259 European occupation, effects of in St. Helena, 283 European plants in New Zealand, 477 in Chile and Fuegia, 489 Everett, Mr., on raised coral-reefs in the Philippines 362 Evolution necessitates continuity, 68 Excentricity and precession
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