The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods, the body whorl, or last whorl, is the most formed and largest whorl of a spiral or helical shell, terminating in the aperture, it is called the "body whorl" because most of the body of the soft parts of the animal fits into this whorl. The proportional size of the body whorl in gastropod shells differs according to the actual shell morphology. For shells in which the rate of whorl expansion of each revolution around the axis is high, the aperture and the body whorl are large, the shell tends to be low spired; the shell of the abalone is a good example of this kind of shell. The opposite tendency can sometimes create a high spire with little whorl increase per revolution. In these instances, e.g. in the shell of Turritella species, both the body whorl and the aperture are small. In mollusc shells where there is no elevation at all to the spire, only moderate whorl expansion, the body whorl can sometimes still represent a large part of the shell, e.g. in some species in the family Planorbidae, such as the genus Segmentina.
The body chamber or living chamber in shelled cephalopod mollusks is an equivalent space, is sometimes called the body whorl. It is the last chamber in the shell of a nautiloid or ammonoid; the body of the animal occupies the living chamber, apart from the siphuncle which extends through the rest of the septa to provide buoyancy
The transverse plane or axial plane is an imaginary plane that divides the body into superior and inferior parts. It is perpendicular to sagittal plane, it is one of the planes of the body used to describe the location of body parts in relation to each other. Transverse thoracic plane Xiphosternal plane Transpyloric plane Subcostal plane Umbilical plane Supracristal plane Intertubercular plane Interspinous plane The transverse thoracic plane Plane through T4 & T5 vertebral junction and sternal angle of Louis. Marks the: Attachment of costal cartilage of rib 2 at the sternal angle. Located at the level of S1. Anatomical terms of location Horizontal plane Coronal plane Sagittal plane
The Permian is a geologic period and system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago, to the beginning of the Triassic period 251.902 Mya. It is the last period of the Paleozoic era; the concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the city of Perm. The Permian witnessed the diversification of the early amniotes into the ancestral groups of the mammals, turtles and archosaurs; the world at the time was dominated by two continents known as Pangaea and Siberia, surrounded by a global ocean called Panthalassa. The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, who could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors; the Permian ended with the Permian–Triassic extinction event, the largest mass extinction in Earth's history, in which nearly 96% of marine species and 70% of terrestrial species died out.
It would take well into the Triassic for life to recover from this catastrophe. Recovery from the Permian–Triassic extinction event was protracted; the term "Permian" was introduced into geology in 1841 by Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Édouard de Verneuil; the region now lies in the Perm Krai of Russia. Official ICS 2017 subdivisions of the Permian System from most recent to most ancient rock layers are: Lopingian epoch Changhsingian Wuchiapingian Others: Waiitian Makabewan Ochoan Guadalupian epoch Capitanian stage Wordian stage Roadian stage Others: Kazanian or Maokovian Braxtonian stage Cisuralian epoch Kungurian stage Artinskian stage Sakmarian stage Asselian stage Others: Telfordian Mangapirian Sea levels in the Permian remained low, near-shore environments were reduced as all major landmasses collected into a single continent—Pangaea; this could have in part caused the widespread extinctions of marine species at the end of the period by reducing shallow coastal areas preferred by many marine organisms.
During the Permian, all the Earth's major landmasses were collected into a single supercontinent known as Pangaea. Pangaea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean, the Paleo-Tethys Ocean, a large ocean that existed between Asia and Gondwana; the Cimmeria continent rifted away from Gondwana and drifted north to Laurasia, causing the Paleo-Tethys Ocean to shrink. A new ocean was growing on its southern end, the Tethys Ocean, an ocean that would dominate much of the Mesozoic era. Large continental landmass interiors experience climates with extreme variations of heat and cold and monsoon conditions with seasonal rainfall patterns. Deserts seem to have been widespread on Pangaea; such dry conditions favored gymnosperms, plants with seeds enclosed in a protective cover, over plants such as ferns that disperse spores in a wetter environment. The first modern trees appeared in the Permian. Three general areas are noted for their extensive Permian deposits—the Ural Mountains and the southwest of North America, including the Texas red beds.
The Permian Basin in the U. S. states of Texas and New Mexico is so named because it has one of the thickest deposits of Permian rocks in the world. The climate in the Permian was quite varied. At the start of the Permian, the Earth was still in an ice age. Glaciers receded around the mid-Permian period as the climate warmed, drying the continent's interiors. In the late Permian period, the drying continued although the temperature cycled between warm and cool cycles. Permian marine deposits are rich in fossil mollusks and brachiopods. Fossilized shells of two kinds of invertebrates are used to identify Permian strata and correlate them between sites: fusulinids, a kind of shelled amoeba-like protist, one of the foraminiferans, ammonoids, shelled cephalopods that are distant relatives of the modern nautilus. By the close of the Permian, trilobites and a host of other marine groups became extinct. Terrestrial life in the Permian included diverse plants, fungi and various types of tetrapods; the period saw a massive desert covering the interior of Pangaea.
The warm zone spread in the northern hemisphere. The rocks formed at that time were stained red by iron oxides, the result of intense heating by the sun of a surface devoid of vegetation cover. A number of older types of plants and animals became marginal elements; the Permian began with the Carboniferous flora still flourishing. About the middle of the Permian a major transition in vegetation began; the swamp-loving
Lithuania the Republic of Lithuania, is a country in the Baltic region of Europe. Lithuania is considered to be one of the Baltic states, it is situated to the east of Sweden and Denmark. It is bordered by Latvia to the north, Belarus to the east and south, Poland to the south, Kaliningrad Oblast to the southwest. Lithuania has an estimated population of 2.8 million people as of 2019, its capital and largest city is Vilnius. Other major cities are Klaipėda. Lithuanians are Baltic people; the official language, along with Latvian, is one of only two living languages in the Baltic branch of the Indo-European language family. For centuries, the southeastern shores of the Baltic Sea were inhabited by various Baltic tribes. In the 1230s, the Lithuanian lands were united by Mindaugas, the King of Lithuania, the first unified Lithuanian state, the Kingdom of Lithuania, was created on 6 July 1253. During the 14th century, the Grand Duchy of Lithuania was the largest country in Europe. With the Lublin Union of 1569, Lithuania and Poland formed a voluntary two-state personal union, the Polish–Lithuanian Commonwealth.
The Commonwealth lasted more than two centuries, until neighbouring countries systematically dismantled it from 1772 to 1795, with the Russian Empire annexing most of Lithuania's territory. As World War I neared its end, Lithuania's Act of Independence was signed on 16 February 1918, declaring the founding of the modern Republic of Lithuania. In the midst of the Second World War, Lithuania was first occupied by the Soviet Union and by Nazi Germany; as World War II neared its end and the Germans retreated, the Soviet Union reoccupied Lithuania. On 11 March 1990, a year before the formal dissolution of the Soviet Union, Lithuania became the first Baltic state to declare itself independent, resulting in the restoration of an independent State of Lithuania. Lithuania is a developed country, it is a member of the European Union, the Council of Europe, Schengen Agreement, NATO and OECD. It is a member of the Nordic Investment Bank, part of Nordic-Baltic cooperation of Northern European countries; the United Nations Human Development Index lists Lithuania as a "very high human development" country.
The first known record of the name of Lithuania is in a 9 March 1009 story of Saint Bruno in the Quedlinburg Chronicle. The Chronicle recorded a Latinized form of the name Lietuva: Litua. Due to the lack of reliable evidence, the true meaning of the name is unknown. Nowadays, scholars still debate the meaning of the word and there are a few plausible versions. Since Lietuva has a suffix, the original word should have no suffix. A candidate is Lietā; because many Baltic ethnonyms originated from hydronyms, linguists have searched for its origin among local hydronyms. Such names evolved through the following process: hydronym → toponym → ethnonym. Lietava, a small river not far from Kernavė, the core area of the early Lithuanian state and a possible first capital of the eventual Grand Duchy of Lithuania, is credited as the source of the name. However, the river is small and some find it improbable that such a small and local object could have lent its name to an entire nation. On the other hand, such a naming is not unprecedented in world history.
Artūras Dubonis proposed another hypothesis. From the middle of the 13th century, leičiai were a distinct warrior social group of the Lithuanian society subordinate to the Lithuanian ruler or the state itself; the word leičiai is used in the 14–16th-century historical sources as an ethnonym for Lithuanians and is still used poetically or in historical contexts, in the Latvian language, related to Lithuanian. The first people settled in the territory of Lithuania after the last glacial period in the 10th millennium BC: Kunda and Narva cultures, they did not form stable settlements. In the 8th millennium BC, the climate became much warmer, forests developed; the inhabitants of what is now Lithuania traveled less and engaged in local hunting and fresh-water fishing. Agriculture did not emerge until the 3rd millennium BC due to a harsh climate and terrain and a lack of suitable tools to cultivate the land. Crafts and trade started to form at this time. Over a millennium, the Indo-Europeans, who arrived in the 3rd – 2nd millennium BC, mixed with the local population and formed various Baltic tribes.
The Baltic tribes did not maintain close cultural or political contacts with the Roman Empire, but they did maintain trade contacts. Tacitus, in his study Germania, described the Aesti people, inhabitants of the south-eastern Baltic Sea shores who were Balts, around the year 97 AD; the Western Balts became known to outside chroniclers first. Ptolemy in the 2nd century AD knew of the Galindians and Yotvingians, early medieval chroniclers mentioned Old Prussians and Semigallians; the Lithuanian language is considered to be conservative for its close connection to Indo-European roots. It is believed to have differentiated from the Latvian language, the most related existing language, around the 7th century. Traditional Lithuanian pagan customs and mythology, with many archaic elements, were long preserved. Rulers' bodies were cremated up until the conversion to Christianity: the descriptions of the cremation ceremonies of the grand d
Ernst Friedrich, Baron von Schlotheim
Ernst Friedrich, Freiherr von Schlotheim, German palaeontologist and politician, was born in Allmenshausen, Schwarzburg-Sondershausen. He was Privy President of the Chamber at the court of Gotha. Becoming interested in geology he gathered a extensive collection of fossils. In 1804 he published descriptions and illustrations of remarkable remains of plants, Ein Beitrag zur Flora der Vorwelt, his more important work was entitled Die Petrefactenkunde. In this he incorporated the plates used in his previous memoir and supplemented it by a folio atlas, in which he illustrated his collection of petrified and fossil remains of the animal and vegetable kingdom of a former world. For the first time in Germany the fossils were named according to the binomial system of Linnaeus, his specimens are preserved in the Berlin Museum. He died at Gotha; this article incorporates text from a publication now in the public domain: Chisholm, Hugh, ed.. "Schlotheim, Ernst Friedrich, Baron von". Encyclopædia Britannica. Cambridge University Press
Estonia the Republic of Estonia, is a country in North East Europe. It is bordered to the north by the Gulf of Finland with Finland on the other side, to the west by the Baltic Sea with Sweden on the other side, to the south by Latvia, to the east by Lake Peipus and Russia; the territory of Estonia consists of a mainland and 2,222 islands in the Baltic Sea, covering a total area of 45,227 km2, water 2,839 km2, land area 42,388 km2, is influenced by a humid continental climate. The official language of the country, Estonian, is the third most spoken Finno-Ugric language; the territory of Estonia has been inhabited since at least 9,000 B. C. Ancient Estonians were some of the last European pagans to be Christianized, following the Livonian Crusade in the 13th century. After centuries of successive rule by Germans, Swedes and Russians, a distinct Estonian national identity began to emerge in the 19th and early 20th centuries; this culminated in independence from Russia in 1920 after a brief War of Independence at the end of World War I.
Democratic, after the Great Depression Estonia was governed by authoritarian rule since 1934 during the Era of Silence. During World War II, Estonia was contested and occupied by the Soviet Union and Germany being incorporated into the former as the Estonian Soviet Socialist Republic. After the loss of its de facto independence, Estonia's de jure state continuity was preserved by diplomatic representatives and the government-in-exile. In 1987 the peaceful Singing Revolution began against Soviet rule, resulting in the restoration of de facto independence on 20 August 1991; the sovereign state of Estonia is a democratic unitary parliamentary republic divided into fifteen counties. Its capital and largest city is Tallinn. With a population of 1.3 million, it is one of the least-populous member states of the European Union since joining in 2004, the economic monetary Eurozone, Organisation for Economic Co-operation and Development, Schengen Area, of the Western military alliance of the North Atlantic Treaty Organization.
It is a developed country with an advanced, high-income economy, among the fastest-growing in the EU. Estonia ranks high in the Human Development Index, performs favourably in measurements of economic freedom, civil liberties and press freedom. Estonian citizens are provided with universal health care, free education, the longest-paid maternity leave in the OECD. One of the world's most digitally advanced societies, in 2005 Estonia became the first state to hold elections over the Internet, in 2014 the first state to provide e-residency. In the Estonian language the oldest known endonym of the Estonians was maarahvas, meaning "country people" or "people of the soil"; the land inhabited by Estonians was called Maavald meaning "Country Realm" or "Land Realm". One hypothesis regarding the modern name of Estonia derives it from the Aesti, a people described by the Roman historian Tacitus in his Germania; the historic Aesti were Baltic people, whereas the modern Estonians are Finno-Ugric. The geographical areas of the Aesti and of Estonia do not match, with the Aesti living farther south.
Ancient Scandinavian sagas refer to an area called Eistland, as the country is still called in Icelandic, with close parallels to the Danish, Dutch and Norwegian terms Estland for the country. Early Latin and other ancient versions of the name include Hestia. Esthonia was a common alternative English spelling before 1921. Human settlement in Estonia became possible 13,000 to 11,000 years ago, when the ice from the last glacial era melted; the oldest known settlement in Estonia is the Pulli settlement, on the banks of the river Pärnu, near the town of Sindi, in south-western Estonia. According to radiocarbon dating it was settled around 11,000 years ago; the earliest human inhabitation during the Mesolithic period is connected to the Kunda culture, named after the town of Kunda in northern Estonia. At that time the country was covered with forests, people lived in semi-nomadic communities near bodies of water. Subsistence activities consisted of hunting and fishing. Around 4900 BC appear ceramics of the neolithic period, known as Narva culture.
Starting from around 3200 BC the Corded Ware culture appeared. The Bronze Age started around 1800 BC, saw the establishment of the first hill fort settlements. A transition from hunting-fishing-gathering subsistence to single-farm-based settlement started around 1000 BC, was complete by the beginning of the Iron Age around 500 BC; the large amount of bronze objects indicate the existence of active communication with Scandinavian and Germanic tribes. A more troubled and war-ridden middle Iron Age followed, with external threats appearing from different directions. Several Scandinavian sagas referred to major confrontations with Estonians, notably when Estonians defeated and killed the Swedish king Ingvar. Similar threats appeared in the east. In 1030 Yaroslav the Wise established a fort in modern-day Tartu. Around the 11th century, the Scandinavian Viking era around the Baltic Sea was succeeded by the Baltic Viking era, with seaborne
The Carboniferous is a geologic period and system that spans 60 million years from the end of the Devonian Period 358.9 million years ago, to the beginning of the Permian Period, 298.9 Mya. The name Carboniferous means "coal-bearing" and derives from the Latin words carbō and ferō, was coined by geologists William Conybeare and William Phillips in 1822. Based on a study of the British rock succession, it was the first of the modern'system' names to be employed, reflects the fact that many coal beds were formed globally during that time; the Carboniferous is treated in North America as two geological periods, the earlier Mississippian and the Pennsylvanian. Terrestrial animal life was well established by the Carboniferous period. Amphibians were the dominant land vertebrates, of which one branch would evolve into amniotes, the first terrestrial vertebrates. Arthropods were very common, many were much larger than those of today. Vast swaths of forest covered the land, which would be laid down and become the coal beds characteristic of the Carboniferous stratigraphy evident today.
The atmospheric content of oxygen reached its highest levels in geological history during the period, 35% compared with 21% today, allowing terrestrial invertebrates to evolve to great size. The half of the period experienced glaciations, low sea level, mountain building as the continents collided to form Pangaea. A minor marine and terrestrial extinction event, the Carboniferous rainforest collapse, occurred at the end of the period, caused by climate change. In the United States the Carboniferous is broken into Mississippian and Pennsylvanian subperiods; the Mississippian is about twice as long as the Pennsylvanian, but due to the large thickness of coal-bearing deposits with Pennsylvanian ages in Europe and North America, the two subperiods were long thought to have been more or less equal in duration. In Europe the Lower Carboniferous sub-system is known as the Dinantian, comprising the Tournaisian and Visean Series, dated at 362.5-332.9 Ma, the Upper Carboniferous sub-system is known as the Silesian, comprising the Namurian and Stephanian Series, dated at 332.9-298.9 Ma.
The Silesian is contemporaneous with the late Mississippian Serpukhovian plus the Pennsylvanian. In Britain the Dinantian is traditionally known as the Carboniferous Limestone, the Namurian as the Millstone Grit, the Westphalian as the Coal Measures and Pennant Sandstone; the International Commission on Stratigraphy faunal stages from youngest to oldest, together with some of their regional subdivisions, are: A global drop in sea level at the end of the Devonian reversed early in the Carboniferous. There was a drop in south polar temperatures; these conditions had little effect in the deep tropics, where lush swamps to become coal, flourished to within 30 degrees of the northernmost glaciers. Mid-Carboniferous, a drop in sea level precipitated a major marine extinction, one that hit crinoids and ammonites hard; this sea level drop and the associated unconformity in North America separate the Mississippian subperiod from the Pennsylvanian subperiod. This happened about 323 million years ago, at the onset of the Permo-Carboniferous Glaciation.
The Carboniferous was a time of active mountain-building as the supercontinent Pangaea came together. The southern continents remained tied together in the supercontinent Gondwana, which collided with North America–Europe along the present line of eastern North America; this continental collision resulted in the Hercynian orogeny in Europe, the Alleghenian orogeny in North America. In the same time frame, much of present eastern Eurasian plate welded itself to Europe along the line of the Ural Mountains. Most of the Mesozoic supercontinent of Pangea was now assembled, although North China, South China continents were still separated from Laurasia; the Late Carboniferous Pangaea was shaped like an "O." There were two major oceans in the Carboniferous—Panthalassa and Paleo-Tethys, inside the "O" in the Carboniferous Pangaea. Other minor oceans were shrinking and closed - Rheic Ocean, the small, shallow Ural Ocean and Proto-Tethys Ocean. Average global temperatures in the Early Carboniferous Period were high: 20 °C.
However, cooling during the Middle Carboniferous reduced average global temperatures to about 12 °C. Lack of growth rings of fossilized trees suggest a lack of seasons of a tropical climate. Glaciations in Gondwana, triggered by Gondwana's southward movement, continued into the Permian and because of the lack of clear markers and breaks, the deposits of this glacial period are referred to as Permo-Carboniferous in age; the cooling and drying of the climate led to the Carboniferous Rainforest Collapse during the late Carboniferous. Tropical rainforests fragmented and were devastated by climate change. Carboniferous rocks in Europe and eastern North America consist of a repeated sequence of limestone, sandstone and coal beds. In North America, the early Carboniferous is marine