THE POWERS OF DISPERSAL OF ANIMALS AND PLANTS. Importance of the Doctrine of Evolution-The Origin of New Species-Variation in Animals-The amount of variation in North American Birds-How new species arise from a variable species-Definition and Origin of Genera-Cause of the extinction of Species-The rise and decay of Species and Genera-Discontinuous specific areas, why rare-Discontinuity of the area of Parus palustris-Discontinuity of Emberiza schoeniclus-The European and Japanese Jays-Supposed examples of discontinuity among North American Birds-Distribution and antiquity of Families-Discontinuity a proof of antiquity-Concluding Remarks The Geographical Divisions of the Globe do not correspond to Zoological Divisions-The range of British Mammals as indicating a Zoological Region-Range of East Asian and North African Mammals-The Range of British Birds-Range of East Asian Birds-The limits of the Palæarctic Region-Characteristic features of the Palæarctic Region-Definition and characteristic groups of the Ethiopian Region-Of the Oriental Region-Of the Australian Region-Of the Nearctic Region-Of the Neotropical Region-Comparison of Zoological Regions with the Geographical Divisions of the Globe Importance of Locality as an essential character of Species-Areas of Distribution-Extent and Limitations of Specific Areas-Specific range of Birds-Generic Areas-Separate and overlapping areas-The species of Tits as illustrating Areas of Distribution-The distribution of the species of Jays-Discontinuous generic areas-Peculiarities of generic and family distribution-General features of overlapping and discontinuous areas-Restricted areas of Families-The distribution of OrdersĬLASSIFICATION OF THE FACTS OF DISTRIBUTION.-ZOOLOGICAL REGIONS. Remarkable Contrasts in the distribution of Animals-Britain and Japan-Australia and New Zealand-Bali and Lombok-Florida and Bahama Islands-Brazil and Africa-Borneo, Madagascar, and Celebes-Problems in Distribution to be found in every country-Can be solved only by the combination of many distinct lines of inquiry, biological and physical-Islands offer the best subjects for the study of distribution-Outline of the subjects to be discussed in the present volume ![]() THE DISPERSAL OF ORGANISMS ITS PHENOMENA, LAWS, AND CAUSES. ![]() Conversely, his enthusiasm for spiritualism and vehement opposition to vaccination do not enhance his scientific reputation.Introduction and Commentary by Lawrence R. He was also very interested in land nationalization and conservation, shaped partly by a meeting with John Muir on a trip to the USA. His liberal worldview encouraged him to resist Francis Galton’s early ideas on eugenics, with Wallace thinking that education, equality and women’s emancipation were the best ways of improving humanity’s condition. He thought at length about human evolution and, although extremely liberal in his day, many of his ideas (as with those of many of his contemporaries) do not stand well today a particular low was choosing to present a paper to the overtly racist Anthropological Society of London, instead of the less problematic Ethnological Society. He also had many other interests, which posterity has viewed variably. During the course of their preparations, Wallace and Bates read Darwin’s Beagle journal, as well as key works by Humboldt, Lyell and Malthus that were so influential in Darwin’s own thinking on evolution.Īlongside natural selection, Wallace will be best remembered for biogeography, something that his field experience made him especially suited to appreciate. Bates and Wallace encouraged one another’s enthusiasm for collecting, until they managed to get funding for a joint collecting expedition to the Amazon, departing in 1848. Particularly important was his meeting with another young amateur entomologist, Henry Walter Bates (subsequently the discoverer of Batesian mimicry), during Wallace’s brief period as a schoolmaster in Leicester. This work took him all over the countryside of England and Wales, giving him the opportunity to collect plants and insects. Wallace was educated in the local schools there until the age of 14, when he became an apprentice surveyor, working with his brother. When Wallace was three years old, the family moved from this Welsh rural idyll to the town of Hertford, immediately north of London. ![]() His parents were financially struggling members of the lower middle class, and money woes would accompany Wallace for all of his life. Alfred Russel Wallace was born on 8 January 1823 near Usk, now in Wales but in a region historically disputed with England.
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