Keywords: Migração, Alimentação, Animalia, Aves, Biologia marinha, Biótopo, Enguia, Humano, Peixe
Uma migração ocorre quando uma população de seres vivos se move de um biótopo para outro, normalmente em busca de melhores condições de vida, seja em termos de alimentação, de temperatura, de trabalho (nos seres humanos), ou para fugirem a inimigos que se instalaram no seu biótopo.
As migrações podem ser temporárias, quando a população regressa ao seu biótopo de origem, ou permanentes, quando a população se instala indefinidamente no novo biótopo.
Migrações temporárias são conhecidas em muitas espécies de animais e podem ter periodicidades muito diferentes, desde as migrações diárias, normalmente verticais do plâncton na coluna de água (ver biologia marinha), anuais como as das andorinhas e de outras aves e de muitos animais terrestres, ou plurianuais como as das enguias e de outros peixes.
Migration occurs when living things move from one biome to another. In most cases organisms migrate to avoid local shortages of food, usually caused by winter. Birds often migrate. The longest known migration is that of the Arctic Tern, which migrates from the Arctic to the Antarctic and back each year. Whales, butterflies, moths, and lemmings are also known to migrate. The periodic migration of flocks of locusts is a phenomenon recorded since Biblical times. Human migrations on the largest scale are discussed under two entries at Wikipedia: · Human migration discusses mass migrations in history and in modern times. · Völkerwanderung ("the wandering of the peoples") more specifically discusses the movements of Germanic peoples during the Age of Migrations in Europe that separated Antiquity from the Middle Ages.
The factual accuracy of this article is disputed.
Human migration has taken place at all times and in the greatest variety of circumstances. It has been tribal, national, class and individual. Its causes have been political, economic, religious, or mere love of adventure. Its causes and results are fundamental for the study of ethnology, of political and social history, and of political economy. In its natural origins, it includes the separate migrations first of Homo erectus then of Homo sapiens out of Africa across Eurasia, doubtless using some of the same available land routes north of the Himalayas that were later to become the Silk Road and across the Strait of Gibraltar. Under the form of conquest, the pressures of human migrations affect the grand epochs in history (e.g. the fall of the Western Roman Empire); under the form of colonization migration has transformed the world (e.g. the prehistoric and historic settlements of Australian and the Americas). Forced migration (see population transfer) has been a means of social control under authoritarian regimes, yet under free initiative it is the most powerful factor in social adjustment (e.g. the growth of urban population).
The evolution of Homo sapiens occurred in Africa, where, it seems, the first anatomically modern humans developed. It is thought that Homo sapiens then migrated into the Near East, spreading northeastwards into Europe and eastwards into Asia, from where Australasia and, later, The Americaswere populated.
Indo-European migration into Europe
In comparison to later ages, relatively little is known about the Pre-Indoeuropean inhabitants of "Old Europe". The Basque language remains from that era, as does the indigenous language in Caucasian Georgia. The speakers of Indo-European languages seem to have originated somewhere in the steppes north of the Caspian Sea and to have penetrated into Europe, into the Aegean basin and into the Iranian plateau in several separate waves. The Scythians and Sarmatians were Indo-European peoples whose homeland remained the steppes.
The Indo-European migration has variously been dated to the end of the Neolithic (Corded ware, Marija Gimbutas), the early Neolithic (Starcevo-Körös and Linearbandkeramic, Colin Renfrew) and the late Palaeolithic (Marcel Otte).
Migrações dos Povos da Europa
Historians divide the period of migrations that separated Antiquity from the Middle Ages in Europe into two phases. The first phase, from 300 to 500 AD, saw the movement of Germanic and other tribes and ended with the settlement of these peoples in the areas of the former Western Roman Empire, essentially causing its demise. (See also: Ostrogoths, Visigoths, Burgundians, Suebi, Alamanni Marcomanni).
The second phase, between 500 and 900 AD, saw Slavic, Turkish and other tribes on the move, re-settling in Eastern Europe and gradually making it predominately Slavic. Moreover, more Germanic tribes migrated within Europe during this period, including the Langobards (to Italy), and the Angles, Saxons, and Jutes (to the British Isles). See also: Avars, Huns, Arabs, Vikings, Varangians. The last phase of the migrations saw the coming of the Hungarians to Pannonia.
German historians of the 19th century referred to these Germanic migrations as the Völkerwanderung, the migrations of the peoples.
Other migrations that happened later in the history of Europe generally did not give rise to new states, but disrupted and, to some extent, dominated policy within Europe. Examples are the invasion of the Arabic into Spain - only as late as 1492 the Spanish completed their Reconquista of the Iberian Peninsula - or the settlement of Muslims in south-eastern Europe, as a result of European armies fighting back the Turks in the Balkan, and the unsuccessful attempt to reconquer Palestine during the Crusades, despite the enormous amount of people, pilgrims and huge armies, that participated in them.
The Jewish diaspora across Europe, the Mediterranean and the Middle East formed from voluntary migrations and pogroms.
At the end of the Middle Ages, the Gypsies arrived in Europe (to Iberia and the Balkans) from the Middle East, originating from the Indus river.
Migrações e cicl0s climáticos
The modern field of climate history suggests that the successive waves of Eurasian nomadic movement throughout history had their origins in climatic cycles that have expanded or contracted pastureland in the Central Asia, especially Mongolia and the Altai. People were displaced from their home ground by other tribes trying to find land that could be cultivated, each group pushing the next further to the south and west, into the highlands of Anatolia, the plains of Hungary, into Mesopotamia and the rich pastures of China.
With the art of open-sea navigation involving the most confident and courageous use of the available technologies of boat-building, combined with the most sophisticated understanding of currents and prevailing winds, the Polynesians, starting with the Lapita culture, have proven to be the most successful in the art of navigation, as the Norse adventurers in the North Atlantic and the Arab traders in the Indian Ocean did not create permanent settlements. The Lapita people, which got their name from the archological site in Lapita, New Caledonia, where their characteristic pottery was first discovered, came from Austronesia, probably New Guinea. Their navigation skills took them to the Solomon Islands, around 1600 BC, and later to Fiji and Tonga. By the beginning of the first millennium BC, most of Polynesia was a loose web of thriving cultures who settled on the islands' coasts and lived off the sea. By 500 BC Micronesia was completely colonized.
Polynesian migration patterns also have been studied by linguistic analysis, and recently by analyzing characteristic genetic alleles of today's inhabitants. Both methods resulted in supporting the original archaeological findings, while adding some new and surprising insights.
Metropolitan Museum page on Lapita culture (http://www.metmuseum.org/toah/hd/lapi/hd_lapi.htm)
Migrações dos Povos Africanos
The movement of population, however, has continued under the form of immigration/emigration.
See also the 19th century German view of Völkerwanderung Population transfer Models of migration to the New World Initially taken from parts of the 1911 Encyclopaedia
See also: migrant, population transfer, population genetics. Try the list of peoples at Nomadic people or look under the specific migrating ethnicity that interests you.