Conquest Of Land Research Articles

Evolutionary relationships of the coelacanth, lungfishes, and tetrapods based on the 28S ribosomal RNA gene.

The origin of land vertebrates was one of the major transitions in the history of vertebrates. Yet, despite many studies that are based on either morphology or molecules, the phylogenetic relationships among tetrapods and the other two living groups of lobe-finned fishes, the coelacanth and the lungfishes, are still unresolved and debated. Knowledge of the relationships among these lineages, which originated back in the Devonian, has profound implications for the reconstruction of the evolutionary scenario of the conquest of land. We collected the largest molecular data set on this issue so far, about 3,500 base pairs from seven species of the large 28S nuclear ribosomal gene. All phylogenetic analyses (maximum parsimony, neighbor-joining, and maximum likelihood) point toward the hypothesis that lungfishes and coelacanths form a monophyletic group and are equally closely related to land vertebrates. This evolutionary hypothesis complicates the identification of morphological or physiological preadaptations that might have permitted the common ancestor of tetrapods to colonize land. This is because the reconstruction of its ancestral conditions would be hindered by the difficulty to separate uniquely derived characters from shared derived characters in the coelacanth/lungfish and tetrapod lineages. This molecular phylogeny aids in the reconstruction of morphological evolutionary steps by providing a framework; however, only paleontological evidence can determine the sequence of morphological acquisitions that allowed lobe-finned fishes to colonize land.

The Roots of Mexican Labor Migration

Introduction Contexts of Migration International Labor Migration: The Mexico-U.S. Case Chaudan: Conquest of Lands, Conquest of Peoples The Rise and Structuring of Migration Agriculture, Ejidos, and Agribusiness The Development and Pattern of Chaudan's Migration The Domestic Group and Multigenerational Migration Chaudan, the Town of the Migrants Household, Family and the Rites of Passage Demography, Economy, and Stratification Church, School and Municipio To the North!--Migrant Experience in the United States Running the Gauntlet: The Frontier and the Migrants The Salinas Valley: Agroindustry and the Place of Migrants Migrant to Minority: Migrant Life in Salinas Conclusions Circulatory Migration as a Domestic Strategy and an Institutionalized Process Migrants and the Free Trade Agreement (NAFTA) Glossary of Spanish Terms References and Maps Index

Aragonese exarici in the twelfth century: their status and conditions of landholding

In the late eleventh and twelf th centuries, as the Aragonese fitfully expanded f rom their hardy Pyrenean kingdom into the Upper Ebro River Basin, they subdued and subsequently ruled Muslim lands wi th well-developed urban and agrarian life (1). As the Aragonese conquest of these Muslim lands shaped the geographical boundaries of Aragon, so the Aragonese conquest of the lands' Muslim inhabitants affected the shaping of Christian society. The Aragonese did not cast aside the material Islamic infrastructure they had conquered; instead, they incorporated it into Christian Aragon, partly in order to exploit the resources of the newly conquered lands. Aragonese retention and adoption of Islamic irrigation practices and techniques attest to the influence of the Muslims on Christian society. Another part of the Islamic agrarian structure retained by Christians was the Muslim tenant-farmer, the ash-shank (sharer), in Latin exaricus. In Al-Andalus, the sharik is usually defined as a tenant-farmer, leasing land f rom a landlord who receives a percentage of the crop (2). In its Romance or Latin fo rm, the word shank frequently surfaces

Solar rotation and activity in the past and their possible influence upon the evolution of life

It is proposed that the rotational angular momentum of the lower Main Sequence stars determines the intensity of their magnetic spot activity. As a consequence of this feedback coupling, the stellar rotation and the activity decay exponentially by magnetic braking of the induced stellar flare- and wind-activity. Therefore, the Sun should have rotated much faster and must have shown a very enhanced activity in its early history. This strong solar activity in the past could have had influenced the evolution of terrestrial life, and may explain the stagnation of maritime life for about 2×109 yr, the diversification of species during the Cambrian formation, and the land conquest by life in the upper Silurian system.

Diffusion of Sikhism and recent migration patterns of Sikhs in India

This paper studies the diffusion of Sikhism from its beginnings at the end of the fifteenth century to the present. By focusing on the historical importance of the Punjab plains area, a spatial crossroad, the problems of survival of the Sikh religion are analyzed. Though the Sikhs remain primarily confined to the Punjab plains, limited expansion took place in the first half of the 19th century with Ranjit Singh's conquest of lands beyond Punjab. Starting from the 2nd half of the 19th century when British occupied Punjab, the Sikhs could practice their religion without any persecution. The British preferred the Sikhs in administrative service particularly in the army, which led to migration of Sikhs to different parts of the country. The partition of India in 1947 further accentrated this migration process because a large number of Sikh refugees from Pakistan settled outside Punjab. Moreover, as a result of “push” factor, some agriculturally based Sikhs of Punjab went to cities all over India in search of employment in which they specialized; these were often single male migrants which caused comparatively greater female ratio in some districts of Punjab, whereas, in the urban areas outside of Punjab, there is larger male ratio. At the same time, in Punjab the greater bulk of the Sikh population is rural, which is also true of Indian population as a whole; outside of Punjab, the Sikh population is overwhelmingly urban. Though Sikh diffusion has remained restricted to the Punjab plains, their migration has witnessed a spread in the last 125 years covering different parts of India.

Aspects fonciers de l'aménagement de l'espace rural

Land Ownership and Country Planning - The feudal and peasant conceptions of land ownership have evolved towards m&rcanWe forms. Land is a marketable commodity and it is its price which rules the social and economic division of space. The land policy of local authorities tends to serve as a corrective to this mechanism, which results in favouring the most profitable uses of land to the disadvantage of farm and forest. It tends to introduce a voluntary economy of space depending on planning aims. In rural areas these aims concern the complementarity of — or the competition between — farm development and the development of other activities, in other words between the various functions that society expects rural land to fullfill : the production of goods the basis for activities, scenery, environment etc. Land ownership is often the farming sector's only bargaining power; a sector dominated both economically and socially. Moreover the increase of land values which historically was used as a means of rural development, is tending to no longer be controlled by local rural land owners. This is why land owners widely resist the present official land policy, the social utility of which is often contested. In fact, land policy must take into account the needs of the farm economy together with other needs. From this point of view three strategies can be proposed concerning the land policy aspects of the planning of three main types of zones : areas of urban pressure, devitalized areas and areas of rural development. The first will requide arbitration between conflicting land uses ; the second will require restrictions on a colonial type of land conquest and the third an organization of the coexistence of complementary functions.

Structural co‐variants of land shortage among patrilineal peoples

Abstract One point of difference among New Guinea Highland peoples hinges on whether, and how far, warfare was linked with territorial gains. Among the Kuma of the Wahgi Valley, land conquest was apparently not an issue before European contact. This paper shows how they are now moving to re‐form their old phratries, and finding the disposal of clan land useful in political competition between pacified clans. Comparisons are drawn between Kuma and Central Enga, with special attention to availability of land, agnatic descent, recruitment, and marriage.