:: wikimiki.org ::

Migration

Migration

This article is about non-human migration. For information on humans see Human migration 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. Animals may also migrate to a certain location to breed, as is the case with some fish. The species that periodically migrate are called migratory, those that do not are called resident or sedentary. Bird migration is common. The longest known migration of a bird is that of the Arctic Tern, which migrates from the Arctic to the Antarctic and back each year. Flyways are routes that certain bird species take to migrate. Whales and other mammals, such as gnus, butterflies, moths, eels, and lemmings are also known to migrate. The periodic migration of plagues of locusts is a phenomenon recorded since Biblical times. Human migrations also happen on a large scale, in history and in modern times. Seasonal human migration is very common in agricultural cycles. In archaeology, migrationism describes an interpretative framework where all major cultural changes are explained by large-scale movements of people. Modern transport, particularly the volume and speed of air transport has facilitated the rapid migration of bacteria and viruses which cause diseases. One of the earliest examples is the infamous plague or "black death" which arrived in Europe along trade routes via the Middle East from the Orient. More recently, virulent strains of influenza and AIDS. In geophysics, migration is a process which keeps in account the right positions of samples in sections with dipping reflectors and structural complexity. Piercing migration, where a piece of body jewelry, during or after healing, shifts or is rejected by the body.

External links

- [http://www.swuklink.com/BAAAGDRR.php swuklink.com - Animal Migration] Category:Population genetics Category:Evolutionary biology

Human migration

Human migration denotes any movement of groups of people from one locality to another. Over the course of prehistoric time and in history, humans have been known to make large migrations. This can be compared with periodic passages of groups of animals such as some birds and fishes; see entry Migration. This article concentrates on the historical human migrations. The people who migrate are called migrants, emigrants, immigrants or settlers, depending on historical setting, circumstance and perspective. Migration and population isolation is one of the four evolutionary forces (along with natural selection, genetic drift, and mutation). The study of the distribution of and change in allele (gene variations) frequencies under such influences is the discipline of Population genetics. The movement of populations in modern times has continued under the form of both voluntary migration within one's region, country, or beyond, and involuntary migration (such as forced migration). Different types of migration include:
- Daily human commuting can be compared to the diurnal migration of organisms in the oceans.
- Seasonal human migration is mainly related to agriculture.
- Permanent migration, for the purposes of permanent or long-term stays.
- Local
- Regional
- Rural to Urban
- International In December 2003 The Global Commission on International Migration (GCIM) was launched with the support of Kofi Annan and several countries, with an independent 19-member Commission, threefold mandate and a finite life-span, ending December 2005. Its report, based on regional consultation meetings with stakeholders and scientific reports from leading international migration experts, was published and presented to UN Secretary-General Kofi Annan on 5 October 2005. The 90-page Report, along with supporting evidence, is available on the GCIM website [http://www.gcim.org]

Overview of historical migrations

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 climatic, 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 (Homo sapiens 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. The pressures of human migrations, whether as outright conquest or by slow cultural infiltration and resettlement, have affected 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 Australia and the Americas). Population genetics studied in traditionally settled modern populations have opened a window into the historical patterns of migrations, a technique pioneered by Luigi Luca Cavalli-Sforza. Forced migration (see population transfer) has been a means of social control under authoritarian regimes, yet under free initiative migration is a powerful factor in social adjustment (e.g. the growth of urban populations).

Earliest migrations

population transfer (numbers are millennia before present).]] The evolution of Homo sapiens occurred in Africa, where, it seems, the first anatomically modern humans developed. Our most recent common female ancestor, whom all living human beings share, probably lived roughly 100,000 to 150,000 years ago. It is thought that a part of the Homo sapiens sapiens population then migrated into the Near East, spreading east to Australasia some 60.000 years ago, northwestwards into Europe and eastwards into Asia some 40.000 years ago, and further east to the Americas ca. 30.000 years ago. Oceania was populated some 15.000 years ago.

Spread of Agriculture

Agriculture is believed to have first been practiced some 10,000 years ago in the Fertile Crescent (see Jericho). From there it propagated as a "wave" across Europe, a view supported by Archaeogenetics, reaching northern Europe some 5,000 years ago.

Indo-European migration into Europe

See Proto-Indo-European. In comparison to later ages, relatively little is known about the inhabitants of "Old Europe". They are considered to have been hunter-gathers and to have spoken an unknown language. The Basque language remains from that era, as does the indigenous language in Caucasian Georgia. However, the only remaining people from that era may be the Sami who are genetically diferent to those of the rest of Europe. They seem to have been supplanted before the last Ice Age by speakers of Proto-Indo-European which has given rise to most of the languages of Europe and India. The speakers of the Proto-Indo-European language seem to have originated in Anatolia and to have occupied most of Europe. However during the Ice Age they withdrew into refuges in Iberia, Italy and the Balkans. After the Ice Age they re-colonised Europe with three slightly different genetic pools. It had previously been thought that they originated somewhere in the steppes north of the Black Sea or the Caspian Sea and to have penetrated into Europe, into the Aegean basin and into the Iranian plateau in several separate waves (see Kurgan hypothesis). However, the Kurgan culture, based on the horse, seems to have arrived in Europe later, around 6000BC. The Scythians and Sarmatians were Indo-European peoples whose homeland remained the steppes. The Indo-European migration had variously been dated to the end of the Neolithic (Marija Gimbutas: Corded ware, Yamna, Kurgan), the early Neolithic (Colin Renfrew: Starčevo-Körös, Linearbandkeramic) and the late Palaeolithic (Marcel Otte, Paleolithic Continuity Theory). However genetic studies have recently shown that the migration dates to the end of the Palaeolithic and that the Neolithic farming revolution was a cultural movement rather than a migration.

The Great Migrations

Western historians refer to the period of migrations that separated Antiquity from the Middle Ages in Europe as the Great Migrations or as the Migrations Period. This period is further divided 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 predominantly Slavic. Moreover, more Germanic tribes migrated within Europe during this period, including the Lombards (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 the Pannonian plain. German historians of the 19th century referred to these Germanic migrations as the Völkerwanderung, the migrations of the peoples.

Other Old World migrations

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 Arabs 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. (At the end of the Reconquista, the King and Queen of Spain also expelled the Jews from their country, thus triggering a migration to places such as Eastern Europe and the New World.) The Jewish diaspora across Europe, the Mediterranean and the Middle East formed from voluntary migrations, enslavement, threats of enslavement and pogroms. After the Nazis brought the Holocaust upon Jewish people in the 1940s, there was a vast migration to Palestine, which became home to the nation of Israel as a result. At the end of the Middle Ages, the Roma arrived in Europe (to Iberia and the Balkans) from the Middle East, originating from the Indus river. The two Great Serbian Migrations took place in 1690 and 1737. That is when hundreds of thousands of Serbs started leaving the areas of their medieval Kingdom and Empire that was overrun by the Turks in the 15th century (Kosovo and Metohija), under the leadership of their patriarchs and Orthodox Church priests, and moved to southern parts of the Kingdom of Hungary, today's Vojvodina, northern Serbia. Some observers note that at present migration is directed from South to North.

Polynesian migration

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, if the permanent spread of culture is taken into account, for the Norse adventurers in the North Atlantic and the Arab traders in the Indian Ocean did not create permanent settlements. The Lapita people, who got their name from the archaeological 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 1st 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.

Migrations to the New World

See Models of migration to the New World.

World War II and post-World War II Migrations

See World War II evacuation and expulsion for World War II forced migrations. Provisions of the Potsdam Agreement from 1945 signed by victorious Western Allies and the Soviet Union led to one of the largest European migrations, and definitely the largest in the 20th century. It involved the migration and resettlement of close to or over 20 million people. The largest affected group were 16.5 million Germans expelled from Eastern Europe westwards. The second largest group were Poles, millions of whom were expelled westwards from eastern Kresy region and resettled in the so-called Recovered Territories (see Allies decide Polish border in the article on the Oder-Neisse line). Hundreds of thousands of Ukrainians and some Bielorussians were in the meantime expelled eastwards, from Poland to the Soviet Union. Finally, many of the several hundred thousands Jews remaining in the Eastern Europe after the Holocaust migrated outside Europe to Israel. See also: Minorities in Poland after the War

Migrations and climate cycles

The modern field of climate history suggests that the successive waves of Eurasian nomadic movement throughout history have had their origins in climatic cycles, which have expanded or contracted pastureland in Central Asia, especially Mongolia and the Altai. People were displaced from their home ground by other tribes trying to find land that could be grazed by essential flocks, each group pushing the next further to the south and west, into the highlands of Anatolia, the plains of Hungary, into Mesopotamia or southwards, into the rich pastures of China.

Literature

- Dirk Hoerder, Cultures in Contact. World Migrations in the Second Millennium, Duke University Press 2002

External links

- [http://www.metmuseum.org/toah/hd/lapi/hd_lapi.htm Metropolitan Museum page on Lapita culture]
- National Geographic: [https://www5.nationalgeographic.com/genographic/atlas.html Atlas of the Human Journey] (Haplogroup-based human migration maps)
- [http://www.bradshawfoundation.com/journey/ Journey of Mankind : the Peopling of the World]
- [http://www.pstalker.com/migration/index.htm Stalker's Guide to International Migration]

References

-
- Category:Population

Fish migration

Many types of fish undertake migrations on a regular basis, on time scales ranging from daily to annual, and with distances ranging from a few meters to thousands of kilometers. The purpose usually relates to either feeding or breeding; in some cases the reason for migration is still unknown. Migratory fish are classified according to the following scheme:
- diadromous fish travel between salt and fresh water
- anadromous fish live in the sea mostly, breed in fresh water
- catadromous fish live in fresh water, breed in sea
- amphidromous fish move between fresh and salt water during some part of life cycle, but not for breeding
- potamodromous fish migrate within fresh water only
- oceanodromous fish migrate within salt water only The best-known anadromous fish are salmon, which hatch in small freshwater streams, go down to the sea and live there for several years, then return to the same streams where they were hatched, spawn, and die shortly thereafter. Salmon are capable of going hundreds of kilometers upriver, and human dams must install fish ladders to enable the salmon to get past. The most remarkable catadromous fish are freshwater eels of genus Anguilla, whose larvae drift on the open ocean, sometimes for months or years, before travelling thousands of kilometres back to their original streams. See eel reproduction. Vertical migration is a common daily behavior; many marine types move to the surface at night to feed, then return to the depths. A number of large marines fishes, such as the tuna, migrate north and south annually, following temperature variations in the ocean. These are of great importance to fisheries. Freshwater fish migrations are usually shorter, typically from lake to stream or vice versa, for spawning purposes.

Reference

- Carl E. Bonds, Biology of Fishes, 2nd ed. (Saunders, 1996), pp. 599-605. Category:Ichthyology

Bird migration

Long-distance land bird migration

Many species of land birds migrate very long distances, the most common pattern being for birds to breed in the temperate or arctic northern hemisphere and winter in warmer regions, often in the tropics or the southern hemisphere. There is a strong genetic component to migration in terms of timing and route, but this may be modified by environmental influences. An interesting example where a change of migration route has occurred because of such a geographical barrier is the trend for some Blackcaps in central Europe to migrate west and winter in Britain rather than cross the Alps. The advantage of the migration strategy is that, in the long days of the northern summer, breeding birds have more hours to feed their young on often abundant food supplies, particularly insects. As the days shorten in autumn and food supplies become scarce, the birds can return to warmer regions where the length of the day varies less and there is an all year round food supply. The downside of migration is the hazards of the journey, especially when difficult habitats such as deserts and oceans must be crossed, and weather conditions may be adverse. The risks of predation are also high. The Eleonora's Falcon which breeds on Mediterranean islands has a very late breeding season, timed so that autumn passerine migrants can be hunted to feed its young. Whether a particular species migrates depends on a number of factors. The climate of the breeding area is important, and few species can cope with the harsh winters of inland Canada or northern Eurasia. Thus the Blackbird Turdus merula is migratory in Scandinavia, but not in the milder climate of southern Europe. The nature of the staple food is also important. Most specialist insect eaters are long-distance migrants, and have little choice but to head south in winter. Certain areas, because of their location, have become famous as watchpoints for migrating birds. Examples are the Point Pelee National Park in Canada, and Spurn in England. Drift migration of birds blown off course by the wind can result in "falls" of large numbers of migrants at coastal sites. Another cause of birds occurring outside their normal ranges is the "spring overshoot" in which birds returning to their breeding areas overshoot and end up further north than intended. A mechanism which can lead to great rarities turning up as vagrants thousands of kilometres out of range is reverse migration, where the genetic programming of young birds fails to work properly. Recent research suggests that long-distance passerine migrants are of South American and African, rather than northern hemisphere, evolutionary origins. They are effectively southern species coming north to breed rather than northern species going south to winter.

Broad-winged long distance migrants

Some large broad-winged birds rely on thermal columns of rising hot air to enable them to soar. These include many birds of prey such as vultures, eagles and buzzards, but also storks. Migratory species in these groups have great difficulty crossing large bodies of water, since thermals can only form over land, and these birds cannot maintain active flight for long distances. The Mediterranean and other seas therefore present a major obstacle to soaring birds, which are forced to cross at the narrowest points. This means that massive numbers of large raptors and storks pass through areas such as Gibraltar, Falsterbo and the Bosphorus at migration times. Commoner species, such as the Honey Buzzard, can be counted in hundreds of thousands in autumn. Other barriers, such as mountain ranges, can also cause funnelling, particularly of large diurnal migrants.

Short-distance land bird migration

The long-distance migrants in the previous section are effectively genetically programmed to respond to changing lengths of days. However many species move shorter distances, but may do so only in response to harsh weather conditions. Thus mountain and moorland breeders, such as Wallcreeper and White-throated Dipper, may move only altitudinally to escape the cold higher ground. Other species such as Merlin and Skylark will move further to the coast or to a more southerly region. Species like the Chaffinch are not migratory in Britain, but will move south or to Ireland in very cold weather. Interestingly, in Scandinavia, the female of this species migrates, but not the male, giving rise to the specific name coelebs, a bachelor. Short-distance passerine migrants have two evolutionary origins. Those which have long-distance migrants in the same family, such as the Chiffchaff, are species of southern hemisphere origins which have progressively shortened their return migration so that they stay in the northern hemisphere. Those species which have no long-distance migratory relatives, such as the waxwings, are effectively moving in response to winter weather, rather than enhanced breeding opportunities.

Wildfowl and waders

The typical image of migration is of northern landbirds such as swallows and birds of prey making long flights to the tropics. Many northern-breeding ducks, geese and swans are also long-distance migrants, but need only to move from their arctic breeding grounds far enough south to escape frozen waters. This means that most wildfowl remain in the Northern hemisphere, but in milder countries. For example, the Pink-footed Goose migrates from Iceland to Britain and neighbouring countries. Usually wintering grounds are traditional and learned by the young when they migrate with their parents. Some ducks, such as the Garganey, do move completely or partially into the tropics. A similar situation occurs with waders (called "shorebirds" in North America). Many species, such as Dunlin and Western Sandpiper, undertake long movements from their arctic breeding grounds to warmer locations in the same hemisphere, but others such as Semipalmated Sandpiper travel huge distances to the tropics. Most of the wildfowl are large and powerful, and even the waders are strong fliers. This means that birds wintering in temperate regions have the capacity to make further shorter movements in the event of particularly inclement weather. The same considerations about barriers and detours that apply to long-distance land-bird migration apply to water birds, but in reverse: a large area of land without bodies of water that offer feeding sites is a barrier to a water bird. Open sea may also be a barrier to a bird that feeds in coastal waters. Detours avoiding such barriers are observed: for example, Brent Geese migrating from the Taymyr Peninsula to the Wadden Sea travel via the White Sea coast and the Baltic Sea rather than directly across the Arctic Ocean and northern Scandinavia. For some species of waders, migration success depends on the availability of certain key food resources at stopover points along the migration route. This gives the migrants an opportunity to "refuel" for the next leg of the voyage. Some examples of important stopover locations are the Bay of Fundy and Delaware Bay. Some Alaskan Bar-tailed Godwits have the longest non-stop flight of any migrant, flying 11,000 km to their New Zealand wintering grounds (BTO News 258: 3, 2005). Prior to migration, 55% of their bodyweight is stored fat to fuel this uninterrupted journey.

Seabirds

New Zealand Much of what has been said in the previous section applies to many seabirds. Some, such as the Black Guillemot and some gulls, are quite sedentary; others, such as most of the terns and auks breeding in the temperate northern hemisphere, move south varying distances in winter. The Arctic Tern has the longest-distance migration of any bird, and sees more daylight than any other, moving from its arctic breeding grounds to the antarctic wintering areas. One Arctic Tern, ringed (banded) as a chick on the Farne Islands off the British east coast, reached Melbourne, Australia in just three months from fledging, a sea journey of over 22,000 km (14,000 miles). Seabirds, of course, have the advantage that they can feed on migration. The most pelagic species, mainly in the 'tubenose' order Procellariiformes, are great wanderers, and the albatrosses of the southern oceans may circle the globe as they ride the "roaring forties" outside the breeding season. The tubenoses in general spread thinly over large areas of open ocean, but congregate when food becomes available. Many of them are also among the longest-distance migrants; Sooty Shearwaters nesting on the Falkland Islands migrate 14,000 km (9,000 miles) between the breeding colony and the North Atlantic Ocean off Norway, and some Manx Shearwaters do the same journey in reverse. As they are long-lived birds, they may cover enormous distances during their lives; one record-breaking Manx Shearwater is calculated to have flown 8 million km (5 million miles) during its over-50 year lifespan. Pelagic birding trips attract petrels and other procellarids by tipping "chum", a mixture of fish oil and offal, into the sea. Within minutes, a previously apparently empty ocean is full of petrels, fulmars and shearwaters attracted by the food. A few seabirds, such as Wilson's Petrel and Great Shearwater, breed in the southern hemisphere and migrate north in the southern winter.

The tropics

In the tropics there is little variation in the length of day throughout the year, and it is always warm enough for an adequate food supply. Apart from the seasonal movements of northern hemisphere wintering species, most species are in the broadest sense resident. However many species undergo movements of varying distances depending on the rainfall. Many tropical regions have wet and dry seasons, the monsoons of India being perhaps the best known example. An example of a bird whose distribution is rain associated is the Woodland Kingfisher of west Africa. There are a few species, notably cuckoos, which are genuine long-distance migrants within the tropics. An example is the Lesser Cuckoo, which breeds in India and winters in Africa. In the high mountains, such as the Himalayas and the Andes, there are of course also altitudinal movements of greater or lesser extent by many species.

Australasia

Bird migration is primarily, but not entirely, a Northern-Hemisphere phenomenon. In the Southern Hemisphere, seasonal migration tends to be much less marked. There are several reasons for this. First, the largely uninterrupted expanses of land mass or ocean tend not to funnel migrations into narrow and obvious pathways, making them less obvious to the human observer. Second, at least for terrestrial birds, climatic regions tend to fade into one another over a long distance rather than be entirely separate: this means that rather than make long trips over unsuitable habitat to reach particular destinations, migrant species can usually travel at a relaxed pace, feeding as they go. Short of banding studies it is often not obvious that the birds seen in any particular locality as the seasons change are in fact different members of the same species passing through, gradually working their way north or south. Relatively few Australasian birds migrate in the way that so many European and North American species do. This is largely a matter of geography: the Australasian climate has seasonal extremes no less compelling than those of Europe; however, they are far less predictable and tend to take place over periods both shorter and longer. A couple of weeks of heavy rain in one part or another of the usually dry centre of Australia, for example, produces dramatic plant and invertebrate growth, attracting birds from all directions. This can happen at any time of year, summer or winter and, in any given area, may not happen again for a decade or more. Broader climatic extremes are highly unpredictable also: expected seasonal heat or rain arrives or does not arrive, depending on the vagaries of El Niño. It is commonplace to have stretches of five or ten years at a time when winter rains do not eventuate during the El Niño cycle, and equally common to have La Niña periods which turn arid zones into areas of lush grass and shallow lakes. Long distance migration requires a heavy investment in time and body mass—and, given the random nature of El Niño, an investment with an uncertain return. In broad terms, Australasian birds tend to be sedentary or nomadic, moving on whenever conditions become unfavourable to whichever area happens to be more suitable at the time. There are many exceptions, however. Some species make the long haul to breed in far distant northern climes every year, notably swifts, and a great many wading birds that breed in the Arctic Circle during the southern winter. Many others arrive for the southern spring and summer to breed, then fly to tropical northern Australia, New Guinea, or the islands of South East Asia for the Southern winter. Examples include cuckoos, the Satin Flycatcher, the Dollarbird, and the Rainbow Bee-eater. Others again are altitudinal migrants, moving to higher country during summer, returning to warmer areas in winter such as several robins, or travel north and south with the seasons but within a relatively restricted range. The tiny 10 cm Silvereye is an example: most of the southernmost Tasmanian race crosses the 200 miles of Bass Strait after breeding to disperse into Victoria, South Australia, New South Wales and even southern Queensland, replacing the normal residents who fly still further north, following the band of fertile country along the coast, feeding through the day and travelling mostly at night. The northernmost populations, however, are nomadic rather than migratory, as are the Silvereyes of southern Western Australia, which is bounded by thousands of miles of desert to the north and east, and sea to the south and west.

Study techniques

Bird migration has been studied by a variety of techniques of which ringing has been the oldest. Color marking, use of radar, satellite tracking and use of stable hydrogen isotopes include some of the newer techniques being used to study the migration of birds.

References

- Alerstam, T. (2001). Detours in bird migration. Journal of Theoretical Biology, 209, 319-331.
- Weidensaul, Scott. Living On the Wind: Across the Hemisphere With Migratory Birds. Douglas & McIntyre, 1999.
- Dingle, Hugh. Migration: The Biology of Life on The Move. Oxford Univ. Press, 1996.

External links

- [http://www.trektellen.nl/default.asp?taal=2 Migration counts and ringing records The Netherlands, Belgium, Great Britain and France] Category:Ornithology Category:Migratory birds (Eastern hemisphere) Category:Migratory birds (Western hemisphere) ko:철새 ja:渡り鳥

Arctic Tern

The Arctic Tern (Sterna paradisaea) is a seabird of the tern family Sternidae. This bird has a circumpolar distribution breeding abundantly in arctic and sub-arctic regions of Europe, Asia and North America as far south as Brittany and Massachusetts. This species is strongly migratory, wintering in the Antarctic. This 19,000 km (12,000 mile) journey ensures that this bird sees more daylight than any other creature on the planet. One particularly spectacular example involved an Arctic Tern ringed as a chick not yet able to fly, on the Farne Islands off the Northumberland coast in eastern Britain in summer 1982, which reached Melbourne, Australia in October 1982, a sea journey of over 22,000 km (14,000 miles) in just three months from fledging. The average Arctic Tern in its life will travel a distance equal to going to the moon and back. The Arctic Tern breeds in colonies on coasts, islands and occasionally inland on tundra near water. It lays up to four eggs. It is the most aggressive tern, fiercely defensive of its nest and young, and will attack humans and other large predators, usually striking the top or back of the head. Although it is too small to cause serious injury, it is capable of drawing blood. In this it differs from the Common Tern, which usually veers off at the last moment, relying on bluff to deter predators without actually striking. Other birds can benefit from nesting in an area defended by Arctic Tern. Like all Sterna terns, Arctic Tern feeds by plunge-diving for fish, usually from the sea, though occasionally also fishing in coastal freshwater lagoons. It often dives from a "stepped-hover". The offering of fish by the male to the female is part of the courtship display. This is a medium-sized tern, 33-39cm long with a 66-77cm wingspan. It is most readily confused within its range with the similar Common Tern Sterna hirundo and Roseate Tern Sterna dougalli. Unlike these two, its thin sharp bill is entirely dark red, as are its short legs. Its upperwings are uniformly grey. Its long tail extends beyond the wingtips on the standing bird, unlike Common Tern, but is shorter than that of Roseate Tern. It is not as pale as Roseate Tern, and has longer wings. On the wintering grounds, Arctic Tern also has to be distinguished from the Antarctic Tern Sterna vittata and Kerguelen Tern Sterna virgata; the six-month difference in moult is the best clue here, with Arctic Terns being in winter plumage during the southern summer. In winter, the forehead and underparts are white. Juvenile Arctic Terns lack the extensive ginger coloration of young Common Terns and the scaly appearance of juvenile Roseate Terns. The call is a clear piping, similar to that of the Common Tern, but higher pitched and more strident. Category:Sterna Category:Arctic animals Category:Migratory birds (Eastern hemisphere)

Arctic

The Arctic is the area around the Earth's North Pole. The Arctic includes parts of Russia, Alaska (United States), Canada, Greenland (a territory of Denmark), Iceland, and Scandinavia (Norway, Sweden, and Finland), as well as the Arctic Ocean. There are numerous definitions for the Arctic region. The boundary is generally considered to be north of the Arctic Circle (66° 33’N), which is the limit of the midnight sun and the polar night. Other definitions are based on climate and ecology, such as the 10°C (50°F) July isotherm, which also roughly corresponds to the tree line in most of the Arctic. Socially and politically, the Arctic region includes the northern territories of the eight Arctic states, including Lapland, although by natural science definitions much of this territory is considered subarctic. The Arctic is mostly a vast, ice-covered ocean, surrounded by tree-less, frozen ground, that teems with life, including organisms living in the ice, fish and marine mammals, birds, land animals and human societies. The Arctic region is by its nature a unique area. The cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions. From the perspective of the physical, chemical and biological balance in the world, the Arctic region is in a key position. It reacts sensitively particularly to changes in the climate, which reflect extensively back on the global state of the environment. From the perspective of research into climatic change, the Arctic region is considered a so-called-early warning system. The Arctic is also known as the Land of the Midnight Sun as it is within the Arctic Circle. The name Arctic comes from the ancient Greek αρκτος, meaning 'bear', and is a reference to the constellations of the Great Bear and Little Bear, which are located near the North Star (which is actually part of the Little Bear).

Nature and natural resources

Nature in the Arctic is comparatively clean although there are certain ecologically difficult localized pollution problems that present a serious threat to people’s health living around these pollution sources. Due to the prevailing worldwide sea and air currents, the Arctic area is the fall out region for long-range transport pollutants and in some places the concentrations exceed the levels of densely populated urban areas. The Arctic region includes sizeable potential natural resources (oil, gas, minerals, forest and fish) to which modern technology and the opening up of Russia have given significant new opportunities. The interest of the tourism industry in the cold and exotic Arctic is also on the increase. This is for example, seen in the rise in international tourism as a significant opportunity but also as a threat. The Arctic region is one of the last and most extensive continuous wilderness areas in the world and its significance in preserving biodiversity and genotypes is considerable. The increasing presence of people fragments vital habitats. The Arctic is particularly susceptible to the abrasion of groundcover and to the disturbance of the rare reproduction places of the animals that are characteristic to the region. External link: [http://amap.no/ AMAP - the Arctic Monitoring and Assessment Programme]

Arctic cultures

Also noteworthy is the fact that a significant proportion of the population in the region are indigenous peoples (e.g. the Nenets, Koms, Khants and Sami) who practice subsistence livelihoods such as reindeer husbandry and fishing and whose rights are many times in jeopardy due to "development".
- Aleut
- Athabaskan
- Chukchi
- Inuit
- Inupiaq
- Nenets
- Pomor
- Saami
- Yup'ik External link: [http://www.allthingsarctic.com/people/index.aspx Native peoples]

The changing Arctic

Along with increasing utilization, it is likely that in the coming decades, new investments, industry and building an infrastructure as well as the increasing mobility of goods, services, people and capital are to be expected. These will all have an effect on the environment of the region and on the local conditions of the population and indigenous peoples. The above-described global change is expected to have the overwhelmingly large impact in the near future on the diversity of nature and cultures in the arctic and northern regions and on the recreational value of the Arctic and its natural resources. The impacts from the changes will reflect in many ways on the ecosystems of the region, its biodiversity, livelihoods, social and legal structures and indirectly on almost all life in the region. The Arctic Climate Impact Assessment (ACIA), released in November 2004, details some of the future scenarios for long-term climate change that are already beginning to be seen in the Arctic region today. NOAA tracks the [http://www.arctic.noaa.gov/detect/overview.shtml current state of the Arctic ecosystems and climate] on the near-realtime [http://www.arctic.noaa.gov/detect/ Arctic Change website]. A narrative style is used to highlight land and marine ecosystems, the cryosphere, Arctic and sub-Arctic human impacts, and an overall [http://www.arctic.noaa.gov/detect/indicators.shtml summary] evaluates recent reports against historical information. External links:
- [http://www.acia.uaf.edu/ ACIA Report]
- [http://www.arctic.noaa.gov/detect/ Arctic Change website] - NOAA website provides up-to-date information on the current state of Arctic ecosystems and climate in historical context.

Environmental impact assessment

From the perspective of positive development in the Arctic region, an environmental impact assessment (EIA) is in a key position. In the Arctic region, it is important that in a process, special attention is given to assessing social impacts. It is generally known that scientific information focused on the Arctic region is insufficient, so the actors conducting an EIA do not get sufficient material in order to compile a precise assessment. Developing a dialogue between new actors in the region, business life and the local population is important so that mutual understanding and often conflicting needs for development can be improved. Improving access to information by local inhabitants, well functioning participatory planning and ensuring the optimum use of its results are part of this activity. The horizontal processing of administration by different sectors in society that is required for an EIA necessitates for its support the production of strong multidisciplinary information. Managing and analyzing the above-mentioned multidimensional and demanding process requires combining many scientific fields and methods and further scientific analysis and development of functional models.

International cooperation and politics

The Arctic region is one of the important focuses of international political interest. International Arctic cooperation got underway on a broad scale well over ten years ago. The International Arctic Science Committee (IASC), hundreds of scientists and specialists of the Arctic Council, the Barents Council and its regional cooperation have compiled high quality information

A strategic military region

The Arctic has never been under the political control of any nation although some nations' militaries have attached a strategic importance to the region. In the 1950s and 1960s, the arctic was often used by submarines to test new weapons, sonar equipment, and depth testing. During the Cold War, the Arctic region was extensively monitored by the United States military, since it was the opinion of the said military that the first warnings of a Soviet Union nuclear strike would have been indicated by ICBMs launched over the North Pole towards the United States. The United States placed such importance on the region that two military decorations, the Arctic Service Ribbon and Coast Guard Arctic Service Medal, were established for military duty performed within the arctic circle.

References

- [http://www.arcticcentre.org Arctic Centre, Rovaniemi] Arctic research
- [http://www.wordreference.com/english/definition.asp?en=arctic WordReference.com Dictionary] Etymology
- [http://www.cia.gov/cia/publications/factbook/reference_maps/pdf/arctic.pdf CIA World Factbook 2002 - Arctic Region] Large version of the arctic region map
- [http://www.arctic.noaa.gov Arctic Theme Page] Comprehensive Arctic Resource from NOAA.
- [http://www.beringclimate.noaa.gov Bering Sea Climate and Ecosystem] Current state of the Bering Sea Climate and Ecosystem. Comprehensive resource on the Bering Sea with viewable oceanographic, atmospheric, climatic, biological and fisheries data with ecosystem relevance, recent trends, essays on key Bering Sea issues, maps, photos, animals and more. From NOAA.
- [http://www.unaami.noaa.gov Arctic time series: The Unaami Data collection] Viewable interdisciplinary, diverse collection of Arctic variables from different geographic regions and data types.
- [http://www.allthingsarctic.com/exploration/index.aspx Arctic exploration and history]
- [http://www.allthingsarctic.com/science/index.aspx Arctic research]

External links

- [http://www.arctic-council.org Arctic Council]
- [http://www.arctic.noaa.gov Arctic]
- [http://www.arctic.noaa.gov/detect/ Near-Realtime Arctic Change Indictors]
- [http://maps.grida.no/arctic Arctic Environmental Atlas] Circum-Arctic interactive map, with multiple layers of information
- [http://www.globio.info/region/polar/#arctic GLOBIO Human Impact maps] How does humans influence one of the last remaining wild places on the globe
- [http://www.vitalgraphics.net/arctic.cfm Vital Arctic Graphics] Overview and case studies of the Arctic environment and the Arctic Indigenous Peoples.
- [http://www.canadiangeographic.ca/atlas/themes.aspx?id=artic&lang=En Arctic and Taiga Canadian Atlas]

Flyway

Flyway is a term which designates the aerial flight path of migrating birds. Flyway is also the name of a literary journal out of Iowa State University as the small town of Ames, Iowa, is directly below the central flyway.

Whale

Whales are the largest species of exclusively aquatic placental mammals, members of the order Cetacea, which also includes dolphins and porpoises. They are the largest mammals, the largest vertebrates, and the largest animals in the world. The term whale is ambiguous: it can refer to all cetaceans, to just the larger ones, or only to members of particular families within the order Cetacea. The latter definition is the one followed here. Whales are those cetaceans which are neither dolphins (i.e. members of the families Delphinidae or Platanistoidea), nor porpoises. This can lead to some confusion because Orcas ("Killer Whales") and Pilot Whales have "whale" in their name, but they are dolphins for the purpose of classification.

Origins and taxonomy

Whales, along with most dolphins and porpoises, are descendants of land-living mammals, most likely of the Artiodactyl order. They entered the water roughly 50 million years ago. See evolution of cetaceans for the details [http://news.bbc.co.uk/1/hi/sci/tech/1974869.stm]. Cetaceans are divided into two suborders:
- The baleen whales are characterized by the baleen, a sieve-like structure in the upper jaw made of keratin, which they use to filter plankton from the water. They are the largest whales.
- The toothed whales have teeth and prey on fish and/or squid. An outstanding ability of this group is to sense their surrounding environment through echolocation. A complete up-to-date taxonomical listing of all cetacean species, including all whales, is maintained at the Cetacea article.

Anatomy

Like all mammals, whales breathe air into lungs, are warm-blooded (that is, endothermic), breast-feed their young, and have some (although very little) hair. The whales' ancestors lived on land, and their adaptions to a fully aquatic life are quite striking: The body is fusiform, resembling the streamlined form of a fish. The forelimbs, also called flippers, are paddle-shaped. The end of the tail holds the fluke, or tail fins, which provide propulsion by vertical movement. Although whales generally do not possess hind limbs, some whales (such as sperm whales, baleen whales, and humpback whales) have been seen having rudimentary hind limbs; some even with feet and digits. Most species of whale bear a fin on their backs known as a dorsal fin. Beneath the skin lies a layer of fat, the blubber. It serves as an energy reservoir and also as insulation. Whales have a four-chambered heart. The neck vertebrae are fused in most whales, which provides stability during swimming at the expense of flexibility. Whales breathe through blowholes, located on the top of the head so the animal can remain submerged. Baleen whales have two; toothed whales have one. When exhaling after a dive, a spout can be seen from the right perspective, the shape of which differs among the species. Whales have a unique respiratory system that lets them stay underwater for long periods of time without taking in any oxygen. Some whales, such as the Sperm Whale, can stay underwater for up to two hours holding a single breath. Especially noteworthy is the Blue Whale, the largest known animal that has ever lived. It may be up to 30 meters long and weigh 180 tons.

Behaviour

Blue Whale Main article: Whale behaviour Whales are broadly classed as predators, but their food ranges from microscopic plankton to very large fish. Males are called bulls; females, cows. The young are called calves. Because of their environment (and unlike many animals), whales are conscious breathers: They have to decide when to breathe. So how do they sleep? All mammals sleep, and so do whales, but they cannot afford to fall into an unconscious state for too long, since they need to be conscious in order to breathe. The solution is that only one hemisphere of their brains sleeps at the time, so that whales are never completely asleep, but still get the rest they need. Whales "sleep" around 8 hours a day. Whales also communicate with each other using beautiful lyrical type sounds. Being so large and powerful these sounds are also extremely loud and can be heard for many miles. They have been known to generate about 20,000 acoustic watts of sound at 163 decibels.
- [http://www.makeitlouder.com/Decibel%20Level%20Chart.txt table of sound decibel levels] Whale females give birth to a single calf. Nursing time is long (more than one year in many species), which is associated with a strong bond between mother and young. In most whales reproductive maturity occurs late, typically at seven to ten years. This strategy of reproduction spawns few offspring, but provides each with a high rate of survival. The genital organs are retracted into cavities of the body during swimming, so as to be streamlined and reduce drag. Most whales do not maintain fixed partnerships during mating; in many species the females have several mates each season. At birth the newborn is delivered tail-first, so the risk of drowning is minimized. Whale mothers nurse the young by actively squirting the fatty milk into their mouths, a milk that according to German naturalist Dieffenbach, bears great similarities to cow's milk.

Whale intelligence

For more material in this area, focusing more on dolphins, see cetacean intelligence. Many people believe that cetaceans in general, and whales in particular, are highly intelligent animals. This belief has become a central argument against whaling (killing whales for food or other commercial reasons). There is no universally agreed definition of "intelligence." One commonly used definition is "the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience." Proponents of whale intelligence cite the social behavior of whales and their apparent capacity for language as evidence of a sophisticated intellect. Given the radically different environment of whales and humans, and the size of whales compared to (say) dolphins or chimpanzees, it is extremely difficult to test these views experimentally. One traditional indicator of intelligence is brain capacity, since humans have bigger brains than most other animals. Whales have the largest brain of any animal. A typical sperm whale brain weighs about 7.8 kg, whereas a typical human brain weighs about 1.5 kg. While it may seem that this would indicate that five times greater intelligence, in mammals brain size is in approximate ratio to body size, and most of the extra capacity is used to manage the larger body. A more precise indicator is the brain-body ratio: the size of the brain compared to body mass. Here humans have a decisive advantage. A human brain comprises about 2% of the human body mass, while the sperm whale's brain comprises only 0.02% of its body mass. A cow's brain is four times as large as a whale's on this measurement. On the other hand, a large proportion of a whale's body mass is blubber, which requires no brain power, and this distorts the ratio somewhat. Nevertheless, it is clear that brain size is not a decisive criterion. Hummingbirds have an even higher brain-to-body ratio than humans. The next consideration is the structure of the brain. It is generally agreed that the growth of the neocortex, both absolutely and relative to the rest of the brain, during human evolution, has been responsible for the evolution of intelligence, however defined. In most mammals the neocortex has six layers, and its different functional areas (vision, hearing, etc) are sharply differentiated. The whale neocortex, on the other hand, has only five layers, and there is little differentiation of these layers according to function. This has led some to argue that the whale brain has not significantly evolved since the distant ancestors of the whale took to a marine lifestyle about 50 million years ago. From an evolutionary point of view, this is consistent with the principles of natural selection. Intelligence does not arise spontaneously: like any other animal capacity, it evolves under the pressure of the animal's environment. The human brain has evolved under the pressure of natural selection in a hostile terrestrial environment. The key primate characteristics - bipedalism and the opposable thumb - gave the early hominids the ability to manipulate their environment through the use of technology (by making tools). This unique adaptation created a virtuous cycle: tool-making gave those hominids with larger brains a decisive evolutionary advantage, leading to larger and more sophisticated brains, and thus to more tool-making. This process explains the exponential growth of hominid intelligence over the past million years. By contrast, the whale has faced no such environmental stimuli to brain evolution. Whales live in an unchanging and benign environment with few natural predators. Their sole adaptation to their marine environment has been increasing size. The whale's lifestyle consists of swimming and eating, tasks which fish perform perfectly competently with very small brains. From an evolutionary point of view, there is no reason for whales to have evolved intelligence, since their survival does not require them to perform any tasks for which intelligence is necessary. It is certainly true that whales have a sophisticated social system, and that their communication system may contain some of the elements of true language, although our knowledge of whale communications is not very advanced. These capacities are sometimes confused with intelligence. But many other animals, including insects, have complex social systems, and many others, such as birds, have sophisticated communications. Whales also have very acute hearing, which gives them advanced echo-location capacities analogous to sonar - but so do bats. All this has led many (though far from all) zoologists to the conclusion that there is no convincing evidence for superior whale intelligence.

Whales and Humans

Main article Whaling Most species of large whales are endangered as a result of large-scale whaling during the nineteenth and twentieth centuries. For centuries large whales have been hunted for oil, meat, baleen and ambergris (a perfume ingredient from the intestine of sperm whales). Until the middle of the 20th century, whaling left many populations nearly or fully extinct. The International Whaling Commission introduced an open ended moratorium on all commercial whaling in 1986. For various reasons some exceptions to this moratorium exist; current whaling nations are Norway, Iceland and Japan and the aboriginal communities of Siberia, Alaska and northern Canada. For details, see whaling. Several species of small whales are caught as bycatch in fisheries for other species. In the tuna fishery in the Eastern Tropical Pacific thousands of dolphins used to drown in purse-seine nets, until measures to prevent this were introduced. Fishing gear and deployment modifications, and eco-labelling (dolphin-safe brands of canned tuna), have contributed to an estimated 96% reduction in the mortality of dolphins by tuna fishing vessels in recent years. In many countries, small whales are still hunted for food, oil, meat or bait. Environmentalists have long argued that some cetaceans including whales are endangered by sonar used by advanced navies. In 2003 British and Spanish scientists have suggested in Nature that the sonar is connected to whale beachings and to signs that the beached whales have experienced decompression sickness (see [http://news.bbc.co.uk/2/hi/science/nature/3173942.stm a BBC report about the Nature article] or [http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v425/n6958/full/425575a_fs.html the Nature article itself (requires subscription)]). Mass whale beachings do occur amongst many species (most of them are beaked whales that make use of echolocation system for deep diving). The frequency and size of beachings around the world, recorded over the last 1000 years in religious tracts and more recently in scientific surveys, has been used to estimate the changing population size of various whale species by assuming that the proportion of the total whale population beaching in any one year is constant (reference?). Despite the concerns raised about sonar which may invalidate this assumption, this population estimate technique is still popular today. Researchers in the area (Talpalar & Grossman, 2005) support that is the combination between high pressure environment of deep-diving together with the disturbing effect of the sonar which causes decompression sickness and stranding of whales. Thus, an exaggerated startle response occurring during deep diving may alter orientation cues and produce rapid ascension. This hypothesis is based on direct effect of high pressure in the central nervous system of mammals: depression of synaptic activity and increased neural excitability. Following public concern, the US Defense department has been ordered by the US judiciary to strictly limit use of its Low Frequency Active Sonar during peacetime. Attempts by the UK-based Whale and Dolphin Conservation Society to obtain a public inquiry into the possible dangers of the Royal Navy's equivalent (the "2087" sonar launched in December 2004) have so far failed. The European Parliament on the other hand has requested that EU members resist using the powerful sonar system until an environmental impact study has been carried out. [http://home.businesswire.com/portal/site/google/index.jsp?ndmViewId=news_view&newsId=20041206005421&newsLang=en] Conservationists are also concerned that seismic testing used for oil and gas exploration may also damage the hearing and echolocation capabilities of whales. They also suggest that disturbances in magnetic fields caused by the testing may also be responsible for beaching. [http://www.sustainability.ca/Docs/Impact%20of%20Seismic%20Surveys%20on%20Whales.pdf?CFID=9951883&CFTOKEN=72165442 See e.g. Seismic testing and the impacts of high intensity sound on whales, Lindy Weilgart, Department of Biology Dalhouise University (PDF format)] or a [http://whales.greenpeace.org/news/3aug2001.html typical press release from Greenpeace on the issue]

Whales in culture

The King James Version of the Bible mentions whales four times: "And God created great whales" (Genesis 1:21); "Am I a sea, or a whale, that thou settest a watch over me? (Job 7:12); "Thou art like a young lion of the nations, and thou art as a whale in the seas (Ezekiel 32:2); and "For as Jonas [sic] was three days and three nights in the whale's belly; so shall the Son of man be three days and three nights in the heart of the earth" (Matthew 12:40). Nevertheless, the passages in question do not unambiguously refer to whales; modern translations tend to use other terms; for example the New International Version uses "creatures of the sea"; "monster of the deep"; "monster"; and "huge fish" respectively. The Book of Jonah (in the King James and some other translations) does not use the word "whale" at all, referring throughout to a "fish" or a "great fish": "Now the LORD had prepared a great fish to swallow up Jonah. And Jonah was in the belly of the fish three days and three nights." (Jonah 1:17). This detail was used to dramatic effect in Clarence Darrow's cross-examination of fundamentalist William Jennings Bryan in the 1925 Scopes Trial, as depicted in the drama "Inherit the Wind" by Jerome Lawrence and Robert E. Lee. The hunting of whales is the subject of one of the classics of the English language literary canon, Herman Melville's Moby-Dick. Melville classed whales as "a spouting fish with a horizontal tail", despite science suggesting otherwise the previous century. Melville acknowledged "the grounds upon which Linnaeus would fain have banished the whales from the waters" but says that when he presented them to "my friends Simeon Macey and Charley Coffin, of Nantucket ... they united in the opinion that the reasons set forth were altogether insufficient. Charley profanely hinted they were humbug." Melville's book is an extraordinary work, part adventure story, part metaphysical allegory, and part natural history; it is essentially a complete summary of nineteenth-century knowledge about the biology, ecology and cultural significance of whales. Some cultures associate some level of divinity with the whale, such as in some places in Ghana and the Vietnamese, who occasionally hold funerals for beached whales, a throwback to Vietnam's ancient sea-based Austroasiatic culture. Festivals celebrating whales have sprung in both Sitka and Kodiak Alaska. They feature speakers on marine biology and celebrate the creatures with art, music, whale-watching cruises, and symposiums.

External links

- [http://www.bigvolcano.com.au/human/whaling.htm Australian Whaling History]
- [http://news.bbc.co.uk/1/hi/sci/tech/239966.stm Oldest whale fossil confirms amphibious origins]
- [http://whales.greenpeace.org/ Greenpeace] - anti-whaling site
- [http://www.highnorth.no/Default.asp High North Alliance] - pro-whaling site
- [http://www.cetacea.org/ Cetacea]
- [http://www.pbs.org/wgbh/evolution/library/03/4/l_034_05.html Whale Evolution]
- [http://www.whale-images.com Whale and Dolphin images]
- [http://whaleofatime.com/forum Whale Of A Time Forum] Whales, Dolphins, Porpoises and Cetaceans. Category:Cetaceans ja:クジラ目 ms:Ikan paus

Butterfly

- Superfamily Hesperioidea:

- Hesperiidae

- Superfamily Papilionoidea:

- Papilionidae

- Pieridae

- Nymphalidae

- Lycaenidae

- Riodinidae
A butterfly is a flying insect of the order Lepidoptera belonging to one of the superfamilies Hesperioidea (the skippers) and Papilionoidea (all other butterflies). Some authors would include also members of the superfamily Hedyloidea, the American butterfly moths. Many butterflies have striking colours and patterns on their wings. When touched by humans they tend to lose small numbers of scales, that look like a fine powder. If they lose too many scales the butterfly's ability to fly will be impaired. People who study or collect butterflies (or the closely related moths) are called lepidopterists. Butterfly watching is growing in popularity as a hobby. Several species of butterflies need more sodium than provided by the nectar they drink from flowers. As such, they are attracted to the sodium in salt (which the males often give to the females to ensure fertility). As human sweat contains significant quantities of salt, they sometimes land on people, to the delight of the young at heart everywhere.

The four stages in the lifecycle of a butterfly

Unlike many insects, butterflies do not experience a nymph period, but instead go through a pupal stage which lies between the larva and the adult stage (the imago).
- Egg
- Larva, known as a caterpillar
- Pupa (chrysalis)
- Adult butterfly (imago)

Egg

Butterfly eggs consist of a hard-ridged outer layer of shell, called the chorion. This is lined with a thin coating of wax which prevents the egg from drying out before the larva has had time to fully develop. Each egg contains a number of tiny funnel-shaped openings at one end, called micropyles; the purpose of these holes is to allow sperm to enter and fertilize the egg. Butterfly and moth eggs vary greatly in size between species, but they are all either spherical or ovate.

Larva

Larvae, or caterpillars, are multi-legged eating machines. They consume plant leaves and spend practically all of their time in search of food. Caterpillars mature through a series of stages, called instars. Near the end of each instar the larva undergoes a process called apolysis, in which the cuticle, a mixture of chitin and specialized proteins, is released from the epidermis and the epidermis begins to form a new cuticle beneath. At the end of each instar the larva molts the old cuticle, and the new cuticle rapidly hardens and pigments. Development of butterfly wing patterns begins by the last larval instar. Butterflies belong to the specialized and prolific lineage of holometabolous insects, which means that wings or wing pads are not visible on the outside of the larva, but when larvae are dissected tiny developing "wing disks" can be found on the second and third thoracic segments, in place of the spiracles that are apparent on abdominal segments. Wing disks develop in association with a trachea that runs along the base of the wing, and are surrounded by a thin "peripodial membrane", which is linked to the outer epidermis of the larva by a tiny duct. holometabolous Wing disks are very small until the last larval instar, when they increase dramatically in size, are invaded by branching tracheae from the wing base that precede the formation of the wing veins, and begin to express molecular markers in patterns associated with several landmarks of the wing. Near pupation the wings are forced outside the epidermis under pressure from the hemolymph, and although they are initially quite flexible and fragile, by the time the pupa breaks free of the larval cuticle they have adhered tightly to the outer cuticle of the pupa (in obtect pupae). Within hours the wings form a cuticle so hard and well-joined to the body that pupae can be picked up and handled without damage to the wings.

Pupa

When the larva exceeds a minimum weight at a particular time of day it will stop feeding and begin "wandering" in search of a suitable pupation site, usually the underside of a leaf. The larva transforms into a pupa (chrysalis), which then transforms into a butterfly by metamorphosis. To transform from the miniature wings visible on the outside of the pupa into large structures usable for flight, the pupal wings undergo rapid mitosis and absorb a great deal of nutrients. If one wing is surgically removed early on, the other three will grow to a larger size. In the pupa the wing forms a structure that becomes compressed from top to bottom and pleated from proximal to distal ends as it grows, so that it can rapidly be unfolded to its full adult size. Several boundaries seen in the adult color pattern are marked by changes in the expression of particular transcription factors in the early pupa.

Butterfly

metamorphosis] metamorphosis The adult, sexually mature, stage of the insect is known as the imago. As Lepidoptera, butterflies have four wings that are covered with tiny scales (see photo), but unlike moths, the fore and hindwings are not hooked together, permitting a more graceful flight. A butterfly has six legs; the larva also has six true legs and a number of prolegs. After it emerges from its pupal stage it cannot fly for some time because its wings have not yet unfolded. A newly emerged butterfly needs to spend some time 'inflating' its wings with blood and letting them dry, during which time it is extremely vulnerable to predators. Many species of butterfly are sexually dimorphic. Some butterflies, such as the Monarch butterfly, are migratory. Butterflies are often confused with moths, but there are a few simple differences between them, including colour, habits, and pupating appearance. See the difference between a butterfly and a moth. Butterflies live primarily on nectar from flowers. Some also derive nourishment from pollen, tree sap, rotting fruit, dung, and dissolved minerals in wet sand or dirt. Butterflies are also pollinators.

Classification

pollinator] pollinator pollinator Although the butterflies are classified in two superfamilies, Hesperioidea and Papilionoidea, these are sister taxa, so the butterflies collectively are thought to constitute a true clade. Some modern taxonomists place them all in superfamily Papilionoidea, distinguishing the skippers from the other butterflies at the series level only. There is only one family in the Hesperioidea (or series Hesperiiformes), the skipper family Hesperiidae. The families usually recognised in the Papilionoidea (or Papilioniformes) are:
- Swallowtails and Birdwings, Papilionidae
- Whites or Yellow-Whites, Pieridae
- Blues and Coppers or Gossamer-Winged Butterflies, Lycaenidae
- Metalmark butterflies, Riodinidae
- Brush-footed butterflies, Nymphalidae A major new study (Wahlberg et al., 2005) combining morphological and molecular data concluded that Hesperiidae, Papilionidae, Pieridae, Lycaenidae and Riodinidae could all be strongly supported as monophyletic clades, but the status of Nymphalidae is equivocal. Lycaenidae and Riodinidae were confirmed as sister taxa, and Papilionidae as the outgroup to the rest of the true butterflies, but the location of Pieridae within the pattern of descent was unclear, with different lines of evidence suggesting different conclusions. The data suggested that the Hedyloidea are indeed more closely related to the butterflies than to other moths. Some older taxonomies recognize additional families, for example Danaidae, Heliconiidae, Libytheidae and Satyridae, but modern classifications treat these as subfamilies within the Nymphalidae. There are between 15,000 and 20,000 species of butterflies worldwide. Some well known species include:
- Small Tortoiseshell, Nymphalis urticae
- Small White, Artogeia rapae
- Green-veined White, Artogeia napi
- Monarch butterfly, Danaus plexippus
- Red Admiral, Vanessa atalanta
- Painted Lady or Cosmopolite, Vanessa cardui
- Peacock, Inachis io
- Xerces Blue, Glaucopsyche xerces
- Gulf Fritillary, Agraulis vanillae
- Black Swallowtail, Papilio polyxenes
- Spicebush Swallowtail, Papilio troilus
- Karner Blue, Lycaeides melissa samuelis (endangered)
- Morpho genus
- Troides genus (birdwings; the largest butterflies)
- Speckled Wood, Pararge aegeria

Etymology

An erroneous etymology claims that the word butterfly came from a metathesis of "flutterby"; however, the Old English word was buttorfleoge and a similar word occurs in Dutch, apparently because butterflies were thought to steal milk.

Aerodynamics, Butterflies, and Flutter

Unlike many other members of the insect world, the flight of a butterfly can be explain quantitatively (and quite accurately) using steady-state, non-transitory aerodynamics. The aspect ratio of a butterfly's wing is ideal to be described using thin airfoil theory. The fluttering of the wings merely serves to enforce the Kutta Condition of low-speed aerodynamics.

Field guides to butterflies

Kutta
- Butterflies of North America, Jim P. Brock and Kenn Kaufman (2003)
- Butterflies through Binoculars: The East, Jeffrey Glassberg (1999)
- Butterflies through Binoculars: The West, Jeffrey Glassberg (2001)
- A Field Guide to Eastern Butterflies, Paul Opler (1994)
- A Field Guide to Western Butterflies, Paul Opler (1999)
- Peterson First Guide to Butterflies and Moths, Paul Opler (1994)
- The Millennium Atlas of Butterflies in Britain and Ireland by Jim Asher (Editor), et al.
- Pocket Guide to the Butterflies of Great Britain and Ireland by Richard Lewington
- Butterflies of Britain and Europe (Collins Wildlife Trust Guides) by Michael Chinery
- A Guide to Common Butterflies of Singapore by Steven Neo Say Hian (Singapore Science Centre)
- Butterflies of West Malaysia and Singapore by W.A.Fleming. (Longman Malaysia)
- Las Mariposas de Machu Picchu by Gerardo Lamas (2003)

References

- Pyle, R. M. (1992) Handbook for Butterfly Watchers. Houghton Mifflin. Originally published, 1984. ISBN 0-395-61629-8
- Heppner, J. B., 1998. Classification of Lepidoptera. Holarctic Lepidoptera, Suppl. 1.
- Wahlberg, N., et al. (2005). Synergistic effects of combining morphological and molecular data in resolving the phylogeny of butterflies and skippers. Proceedings of the Royal Society, Series B (Biological Sciences), 272, 1577-1586.

Additional photos

Image:Tagpfauenauge.jpg|Peacock Butterfly Image:Issoria lathonia.jpg

Moth

A moth is an insect closely related to the butterfly. Both are of the order Lepidoptera. The division of Lepidopterans into moths and butterflies is a popular taxonomy, not a scientific one. Sometimes the names "Rhopalocera" (butterflies) and "Heterocera" (moths) are used to formalise the popular distinction. Most species of moths are nocturnal, but there are crepuscular and diurnal species. They can be distinguished from butterflies in several ways. People who study butterflies and/or moths are called lepidopterists; the study of butterflies is known as butterflying, and the study of moths mothing, the latter giving rise to the term mother for someone who takes part in this activity – sometimes written with a hyphen inserted (moth-er) or as moffer to distinguish it from the word for a female parent (in spoken English, confusion does not arise as the two are pronounced differently).

Economic significance of moths

mothing Moths, and more particularly their caterpillars are a major agricultural pest in many parts of the world. The caterpillar of the Gypsy moth causes severe damage to forests in North East USA, where it is an exotic species. The Codling moth also does extensive damage, especially to fruit farms. Other moths are commonly regarded as pests because their larvae eat fabric such as clothes and blankets made from natural proteinaceous fibers such as wool or silk. They are less likely to eat mixed materials containing artificial fibres. There are some reports that they can be repelled by the scent of wood from juniper and cedar, by lavender or by other natural oils. However, many consider this unlikely to prevent infestation. Naphthalene (the chemical used in mothballs) is considered more effective, but there are concerns over its effects on health. Freezing items infested with moth larvae will not kill them. Moths are sturdy and usually require larger amount of pesticide to kill them than mosquitos or flies. Other moths are farmed. Especially the Silkworm (the larva of a moth) is farmed for the silk with which it builds its cocoon. The silk industry produces over 130 million kg of raw silk, worth about 250 million US dollars worldwide.

Attraction to light

cocoon Moths are apparently attracted to light, or more specifically, are known to circle bright objects. The reason for this behaviour is not known. It may be moths navigate by maintaining a constant angular relationship to a bright celestial light (such as the moon), but on encountering a bright artificial light it navigates maintaining a constant angle to the light resulting in the moth flying in a spiral until it hits the light source. However, researchers such as Henry Hsiao suggest the reason for moths circling lights has to do with a visual distortion called a Mach band. Henry Hsiao conjectures that moths, as nocturnal creatures, fly towards the darkest part of the sky in pursuit of safety. Moths are thus inclined to circle ambient objects in the Mach band region, usually at a radius of about one foot, depending on the species. Night blooming flowers usually depend on moths (or bats) for pollination, and artificial lighting can draw moths away from the flowers, affecting the plant's ability to reproduce. Light pollution is coming under increasing scrutiny as a source of many subtle ecological changes.

Moth species

Large and dramatic Moth species include:
- Death's-head Hawkmoth Acherontia sp.
- Luna Moth Actias luna
- Atlas moth Attacus atlas The largest moth in the world
- Emperor Gum Moth Opodiphthera eucalypti Moths that are of economic significance include:
- Gypsy moth Lymantria dispar
- Cotton bollworm or corn earworm a major agricultural pest
- Codling moth
- Light brown apple moth Epiphyas postvittana
- The silkworm Bombyx mori is the larva of a moth. Other notable moths:
- Peppered moth Biston betularia The subject of a now well known study in evolution.

Gallery

Image:Lepidoptere(s).jpg|Lepidopteran on a flower. Image:Moth.jpg|A moth Image:Case moth.jpg|Case Moth Image:Case moth02.jpg|Case Moth Image:Looper moth.jpg|Looper Moth Image:LeopardMoth.jpg|Giant Leopard Moth Image:Rosy Maple Moth.png|Rosy Maple Moth (Dryocampa rubicunda) Image:Moth-Georgia-Oct12005.jpg|Grammia parthenice Tiger Moth Image:Nyctemera.amica.jpg|Nyctemera amica Image:Chelepteryx.collesi.jpg|Chelepteryx collesi (Gray) (Anthelidae) Image:Chelepteryx.collesi.02.jpg|Chelepteryx collesi (Gray) (Anthelidae)

External links

- [http://www.pollinator.com/plant_pol/caterpillars/barbarea_verna2.htm Life cycle photos of the salt marsh moth Estigmene acrea]
- [http://www.ukmoths.force9.co.uk/ UK Moths]
- [http://www.uklepidoptera.co.uk/ UK Lepidoptera]
- [http://www.leps.nl/ Butterflies and Moths of the Netherlands]
- Category:Pollination ja:ガ

Eel

Suborder Anguilloidei
:Anguillidae (freshwater eels) :Heterenchelyidae :Moringuidae (worm eels) :Xenocongridae (false morays) :Muraenidae (moray eels) :Myrocongridae Suborder Nemichthyoidei
:Nemichthyidae (snipe eels) :Serrivomeridae (sawtooth snipe eels) :Cyemidae (bobtail snipe eels) Suborder Congroidei
:Congridae (congers) :Muraenesocidae (conger pikes) :Nettastomatidae (witch eels) :Nessorhamphidae (duckbilled eels) :Derichthyidae (neck eels) :Ophichthidae (snake eels) :Macrocephenchelyidae Suborder Synaphobranchoidei
:Synaphobranchidae :Simenchelyidae (parasitic eels) :Dysommidae Eels are fish of the order Anguilliformes that consists of 2 suborders, 23 families, 110 genii and 400 species. In length they reach from 10 cm. to 3 m., weight from 15 to 65 kg. The number of rays of the gill webbing consists from 6 - 51, sometimes they are absent altogether. Their fins are always spineless. The back and anal fins are long, usually connecting with the tail fin. The belly and chest fins are absent. The shoulder girdle is separate from the skull. The scales are cycloid or absent. The flat and transparent larva of the eel is called a leptocephalus. A young eel is called an elver. Most eels prefer to dwell in shallow waters, hide at the bottom layer of the ocean, sometimes in holes. Only the Anguillidae family comes to fresh water to dwell there (not to breed). Some eels dwell in deep water (in case of family Synaphobranchidae, this comes to a depth of 4000 m.), or are active swimmers (the family Nemichthyidae - to the depth of 500 m.). Most eels are predators. Freshwater eels (unagi) and marine eels (Conger eel, anago) are commonly used in Japanese cuisine. Eels are used in Cantonese and Shanghai cuisine too. The European eel and other freshwater eels are eaten in Europe, the United States, and other places around the world. A traditional London food is jellied eels. The Basque delicacy, angulas, consists of deep-fried elvers.[http://www.buber.net/Basque/Food/food1.html] Spiny eels and halosaurs of the order Notacanthiformes are also very eel-like. These deep-diving fish were in the past considered a sub-order of the Albuliformes. Electric eels are not true eels. They are more closely related to catfish. Uniquely in Europe, hand netting is the only legal way of catching eels in England, and has been practiced for thousands of years on the River Parrett and River Severn. The Anguilliformes (true eels) are an order of bony fishes. Eel skins are used in some wallets and purses. In recent years, cryptozoologists have theorised that the Loch Ness Monster is a giant eel. Loch Ness Monster

Locust

] :For other meanings of the word Locust, see Locust (disambiguation). :For the biological nomenclature, see Grasshopper. Locust is the name given to the swarming phase of short-horned grasshoppers of the family Acrididae. The origins and apparent extinction of certain species of locust—some of which reach 6 inches (15 cm) in length—are unclear. There are species that can breed rapidly under suitable conditions and subsequently become gregarious and migratory. They form bands as nymphs and swarms as adults both of which travel great distances during which they can strip fields rapidly and in so doing greatly damage crop yields. An exacerbating factor in the damage to crops caused by locusts is their ability to adapt to eating almost any food plant. Some examples of Locust species are:-
- Migratory locust (Locusta migratoria)
- Red locust (Nomadracis septemfasciata)
- Australian plague locust (Chortoicetes terminifera)
- Desert locust (Schistocerca gregaria), probably the most important in terms of its very wide distribution (North Africa, Middle East, and Indian subcontinent) and its ability to migrate very widely.
- Rocky Mountain locust (Melanoplus spretus) in North America had some of the largest recorded swarms, but died out in the late 19th century. There is a theory that the Rocky Mountain locust died out because between s

Migration

See also

External links

Human migration

Overview of historical migrations

Earliest migrations

Spread of Agriculture

Indo-European migration into Europe

The Great Migrations

Other Old World migrations

Polynesian migration

Migrations to the New World

World War II and post-World War II Migrations

Migrations and climate cycles

Literature

External links

References

Fish migration

Reference

Bird migration

Long-distance land bird migration

Broad-winged long distance migrants

Short-distance land bird migration

Wildfowl and waders

Seabirds

The tropics

Australasia

Study techniques

See also

References

External links

Arctic Tern

Arctic

Nature and natural resources

Arctic cultures

The changing Arctic

Environmental impact assessment

International cooperation and politics

A strategic military region

References

External links

See also

Flyway

Whale

Origins and taxonomy

Anatomy

Behaviour

Whale intelligence

Whales and Humans

Whales in culture

See also

Further reading

External links

Butterfly

The four stages in the lifecycle of a butterfly

Egg

Larva

Pupa

Butterfly

Classification

Etymology

Aerodynamics, Butterflies, and Flutter

Field guides to butterflies

See also

References

Additional photos

Moth

Economic significance of moths

Attraction to light

Moth species

See also

Gallery

External links

Eel

See also

Locust