105-723: The Sowy River is an artificial drainage channel in Somerset , England, designed to act as a flood relief channel for the River Parrett . Water from the Parrett can be diverted into it just below Langport , and is conveyed to the King's Sedgemoor Drain , which discharges back into the Parrett much nearer to its outfall into the Bristol Channel. Following extensive flooding of the surrounding land in 2014, new culverts to carry
210-584: A national park in 1954, under the 1949 National Parks and Access to the Countryside Act . The highest point in Somerset is Dunkery Beacon on Exmoor, with a maximum elevation of 519 metres (1,703 feet). Over 100 sites in Somerset have been designated as Sites of Special Scientific Interest . The 64 km (40 mi) coastline of the Bristol Channel and Severn Estuary forms part of
315-578: A design capacity of 600 cubic feet per second (17 m/s), in practice this was not achieved, and where required, the right bank was raised by up to 1.6 feet (0.5 m) between Monk’s Leaze Clyce and the A372 at Beer Wall in order to achieve this capacity. The capacity of the channel between Beer Wall and the A361 at Greylake Bridge was increased to 850 cubic feet per second (24 m/s) by raising both banks by up to 1 foot (0.3 m) in places, and by increasing
420-578: A long history of settlement, and are known to have been settled by Mesolithic hunters. Travel in the area was facilitated by the construction of one of the world's oldest known engineered roadways, the Sweet Track , which dates from 3807 BCE or 3806 BCE. The exact age of the henge monument at Stanton Drew stone circles is unknown, but it is believed to be Neolithic . There are numerous Iron Age hill forts , some of which, like Cadbury Castle and Ham Hill , were later reoccupied in
525-466: A population of 965,424. After Bath (101,557), the largest settlements are Weston-super-Mare (82,418), Taunton (60,479), and Yeovil (49,698). Wells (12,000) is a city, the second-smallest by population in England. For local government purposes the county comprises three unitary authority areas: Bath and North East Somerset , North Somerset , and Somerset . Bath and North East Somerset Council
630-528: A small proportion of the Metazoa that to speak of the kingdom Animalia in terms of "Vertebrata" and "Invertebrata" has limited practicality. In the more formal taxonomy of Animalia other attributes that logically should precede the presence or absence of the vertebral column in constructing a cladogram , for example, the presence of a notochord . That would at least circumscribe the Chordata. However, even
735-494: A source of information for forensic investigators. Two of the most commonly studied model organisms nowadays are invertebrates: the fruit fly Drosophila melanogaster and the nematode Caenorhabditis elegans . They have long been the most intensively studied model organisms , and were among the first life-forms to be genetically sequenced. This was facilitated by the severely reduced state of their genomes , but many genes , introns , and linkages have been lost. Analysis of
840-410: A unitary authority for the non-metropolitan county, with the powers of both a district and county council, renamed Somerset Council . The two existing unitary authorities were not altered. A previous attempt to reorganise the county as a unitary authority 2007 was rejected following local opposition. Somerset's local government records date to 1617, longer than those of any other county; a meeting of
945-431: A wide range of invertebrate species, including annelids, molluscs, nematodes and arthropods. One type of invertebrate respiratory system is the open respiratory system composed of spiracles , tracheae, and tracheoles that terrestrial arthropods have to transport metabolic gases to and from tissues. The distribution of spiracles can vary greatly among the many orders of insects, but in general each segment of
1050-527: Is a ceremonial county in South West England . It is bordered by the Bristol Channel , Gloucestershire , and Bristol to the north, Wiltshire to the east and the north-east, Dorset to the south-east, and Devon to the south-west. The largest settlement is the city of Bath , and the county town is Taunton . Somerset is a predominantly rural county, especially to the south and west, with an area of 4,171 km (1,610 sq mi) and
1155-781: Is a member of the West of England Combined Authority . The centre of Somerset is dominated by the Levels , a coastal plain and wetland. The north-east contains part of the Cotswolds uplands and all of the Mendip Hills , which are both national landscapes ; the west contains the Quantock Hills and part of the Blackdown Hills , which are also national landscapes, and most of Exmoor , a national park . The major rivers of
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#17327765184751260-552: Is also included within invertebrates: the Arthropoda, including insects, spiders , crabs , and their kin. All these organisms have a body divided into repeating segments, typically with paired appendages. In addition, they possess a hardened exoskeleton that is periodically shed during growth. Two smaller phyla, the Onychophora and Tardigrada , are close relatives of the arthropods and share some traits with them, excluding
1365-469: Is approximately 10 °C (50.0 °F). Seasonal temperature variation is less extreme than most of the United Kingdom because of the adjacent sea temperatures. The summer months of July and August are the warmest with mean daily maxima of approximately 21 °C (69.8 °F). In winter mean minimum temperatures of 1 °C (33.8 °F) or 2 °C (35.6 °F) are common. In the summer
1470-669: Is drained by the River Parrett while land to the north is drained by the River Axe and the River Brue. The total area of the Levels amounts to about 647.5 square kilometres (160,000 acres) and broadly corresponds to the administrative district of Sedgemoor but also includes the south west of Mendip district . Approximately 70% of the area is grassland and 30% is arable. Stretching about 32 kilometres (20 mi) inland, this expanse of flat land barely rises above sea level. Before it
1575-500: Is easily seen in snails and sea snails , which have helical shells. Slugs appear externally symmetrical, but their pneumostome (breathing hole) is located on the right side. Other gastropods develop external asymmetry, such as Glaucus atlanticus that develops asymmetrical cerata as they mature. The origin of gastropod asymmetry is a subject of scientific debate. Other examples of asymmetry are found in fiddler crabs and hermit crabs . They often have one claw much larger than
1680-473: Is in the law code of King Ine who was the Saxon King of Wessex from 688 to 726 CE, making Somerset along with Hampshire , Wiltshire and Dorset one of the oldest extant units of local government in the world. An alternative suggestion is the name derives from Seo-mere-saetan meaning "settlers by the sea lakes". The same ending can also be seen in the neighbouring Dorset . The Old English name
1785-474: Is not always precise among non-biologists since it does not accurately describe a taxon in the same way that Arthropoda , Vertebrata or Manidae do. Each of these terms describes a valid taxon, phylum , subphylum or family . "Invertebrata" is a term of convenience, not a taxon; it has very little circumscriptional significance except within the Chordata . The Vertebrata as a subphylum comprises such
1890-675: Is part of a larger coalfield which stretches into Gloucestershire . To the north of the Mendip hills is the Chew Valley and to the south, on the clay substrate, are broad valleys which support dairy farming and drain into the Somerset Levels. There is an extensive network of caves , including Wookey Hole, underground rivers, and gorges , including the Cheddar Gorge and Ebbor Gorge . The county has many rivers, including
1995-636: Is particularly salient in eusocial species but applies to other invertebrates as well. Insects recognize information transmitted by other insects. The term invertebrates covers several phyla. One of these are the sponges ( Porifera ). They were long thought to have diverged from other animals early. They lack the complex organization found in most other phyla. Their cells are differentiated, but in most cases not organized into distinct tissues. Sponges typically feed by drawing in water through pores. Some speculate that sponges are not so primitive, but may instead be secondarily simplified. The Ctenophora and
2100-459: Is the chief settlement of the county's only extant borough ). The largest urban areas in terms of population are Bath, Weston-super-Mare , Taunton, Yeovil and Bridgwater . Many settlements developed because of their strategic importance in relation to geographical features, such as river crossings or valleys in ranges of hills. Examples include Axbridge on the River Axe , Castle Cary on
2205-719: Is used in the motto of the county, Sumorsǣte ealle , meaning "all the people of Somerset". Adopted as the motto in 1911, the phrase is taken from the Anglo-Saxon Chronicle . Somerset was a shire of the Anglo-Saxon kingdom of Wessex , and the phrase refers to the wholehearted support the people of Somerset gave to King Alfred in his struggle to save Wessex from Viking invaders. Somerset settlement names are mostly Anglo-Saxon in origin (for example, Bath , Somerton , Wells and Keynsham ), but numerous place names include British Celtic elements, such as
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#17327765184752310-737: The Acanthocephala , or spiny-headed worms, the Gnathostomulida , Micrognathozoa , and the Cycliophora . Also included are two of the most successful animal phyla, the Mollusca and Annelida. The former, which is the second-largest animal phylum by number of described species, includes animals such as snails , clams , and squids , and the latter comprises the segmented worms, such as earthworms and leeches . These two groups have long been considered close relatives because of
2415-464: The Azores high pressure affects the south-west of England, but convective cloud sometimes forms inland, reducing the number of hours of sunshine. Annual sunshine rates are slightly less than the regional average of 1,600 hours. In December 1998 there were 20 days without sun recorded at Yeovilton. Most of the rainfall in the south-west is caused by Atlantic depressions or by convection. Most of
2520-516: The Bath and West of England Society for the Encouragement of Agriculture, Arts, Manufactures and Commerce was founded in 1777 to improve farming methods. Despite this, two decades later agriculturist John Billingsley conducted a survey of the county's agriculture in 1795 and found that agricultural methods could still be improved. Coal mining was an important industry in north Somerset during
2625-622: The Battle of Sedgemoor at Westonzoyland , the last pitched battle fought in England. Arthur Wellesley took his title, Duke of Wellington from the town of Wellington ; he is commemorated on a nearby hill by a large, spotlit obelisk , known as the Wellington Monument . The Industrial Revolution in the Midlands and Northern England spelled the end for most of Somerset's cottage industries. Farming continued to flourish, and
2730-737: The Cnidaria , which includes sea anemones , corals , and jellyfish , are radially symmetric and have digestive chambers with a single opening, which serves as both the mouth and the anus. Both have distinct tissues, but they are not organized into organs . There are only two main germ layers, the ectoderm and endoderm , with only scattered cells between them. As such, they are sometimes called diploblastic . The Echinodermata are radially symmetric and exclusively marine, including starfish (Asteroidea), sea urchins , (Echinoidea), brittle stars (Ophiuroidea), sea cucumbers (Holothuroidea) and feather stars (Crinoidea). The largest animal phylum
2835-842: The Early Middle Ages . On the authority of the future emperor Vespasian , as part of the ongoing expansion of the Roman presence in Britain, the Second Legion Augusta invaded Somerset from the south-east in 47 CE. The county remained part of the Roman Empire until around 409 CE, when the Roman occupation of Britain came to an end. A variety of Roman remains have been found, including Pagans Hill Roman temple in Chew Stoke , Low Ham Roman Villa and
2940-648: The European Parliament . Invertebrate Invertebrates is an umbrella term describing animals that neither develop nor retain a vertebral column (commonly known as a spine or backbone ), which evolved from the notochord . It is a paraphyletic grouping including all animals excluding the chordate subphylum Vertebrata , i.e. vertebrates . Well-known phyla of invertebrates include arthropods , mollusks , annelids , echinoderms , flatworms , cnidarians , and sponges . The majority of animal species are invertebrates; one estimate puts
3045-536: The Nemertea , or ribbon worms, and the Sipuncula . Another phylum is Platyhelminthes , the flatworms. These were originally considered primitive, but it now appears they developed from more complex ancestors. Flatworms are acoelomates , lacking a body cavity, as are their closest relatives, the microscopic Gastrotricha . The Rotifera , or rotifers, are common in aqueous environments. Invertebrates also include
3150-594: The Palaeolithic period, and contain extensive archaeological sites such as those at Cheddar Gorge . Bones from Gough's Cave have been dated to 12,000 BCE, and a complete skeleton, known as Cheddar Man , dates from 7150 BCE . Examples of cave art have been found in Aveline's Hole . Some caves continued to be occupied until modern times, including Wookey Hole . The Somerset Levels —specifically dry points at Glastonbury and Brent Knoll —also have
3255-595: The Phanerozoic . Fossils of invertebrates are commonly used in stratigraphy. Carl Linnaeus divided these animals into only two groups, the Insecta and the now-obsolete Vermes ( worms ). Jean-Baptiste Lamarck , who was appointed to the position of "Curator of Insecta and Vermes" at the Muséum National d'Histoire Naturelle in 1793, both coined the term "invertebrate" to describe such animals and divided
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3360-666: The Protozoa , Porifera , Coelenterata , Platyhelminthes , Nematoda , Annelida , Echinodermata , Mollusca and Arthropoda . Arthropoda include insects , crustaceans and arachnids . By far the largest number of described invertebrate species are insects. The following table lists the number of described extant species for major invertebrate groups as estimated in the IUCN Red List of Threatened Species , 2014.3. The IUCN estimates that 66,178 extant vertebrate species have been described, which means that over 95% of
3465-713: The River Cary , North Petherton on the River Parrett , and Ilminster , where there was a crossing point on the River Isle . Midsomer Norton lies on the River Somer ; while the Wellow Brook and the Fosse Way Roman road run through Radstock. Chard is the most southerly town in Somerset and one of the highest, though at an altitude of 126 m (413 ft) Wiveliscombe is the highest town in
3570-511: The Roman Baths that gave their name to the city of Bath . After the Romans left, Britain was invaded by Anglo-Saxon peoples. By 600 CE they had established control over much of what is now England, but Somerset was still in native British hands. The British held back Saxon advance into the south-west for some time longer, but by the early eighth century King Ine of Wessex had pushed
3675-680: The Second World War the county was a base for troops preparing for the D-Day landings . Some of the hospitals which were built for the casualties of the war remain in use. The Taunton Stop Line was set up to repel a potential German invasion. The remains of its pill boxes can still be seen along the coast, and south through Ilminster and Chard . A number of decoy towns were constructed in Somerset in World War ;II to protect Bristol and other towns. They were designed to mimic
3780-457: The Tonian . Trace fossils such as tracks and burrows found in the late Neoproterozoic Era indicate the presence of triploblastic worms, roughly as large (about 5 mm wide) and complex as earthworms . Around 453 MYA, animals began diversifying, and many of the important groups of invertebrates diverged from one another. Fossils of invertebrates are found in various types of sediment from
3885-545: The gill chamber of their fish hosts ). Neurons differ in invertebrates from mammalian cells. Invertebrates cells fire in response to similar stimuli as mammals, such as tissue trauma, high temperature, or changes in pH. The first invertebrate in which a neuron cell was identified was the medicinal leech , Hirudo medicinalis . Learning and memory using nociceptors in the sea hare, Aplysia has been described. Mollusk neurons are able to detect increasing pressures and tissue trauma. Neurons have been identified in
3990-537: The 18th and 19th centuries, and by 1800 it was prominent in Radstock . The Somerset Coalfield reached its peak production by the 1920s. All the pits have now been closed, the last in 1973. Most of the surface buildings have been removed, and apart from a winding wheel outside Radstock Museum , little evidence of their former existence remains. Further west, the Brendon Hills were mined for iron ore in
4095-718: The 1968 edition of Invertebrate Zoology , it is noted that "division of the Animal Kingdom into vertebrates and invertebrates is artificial and reflects human bias in favor of man's own relatives." The book also points out that the group lumps a vast number of species together, so that no one characteristic describes all invertebrates. In addition, some species included are only remotely related to one another, with some more related to vertebrates than other invertebrates (see Paraphyly ). For many centuries, invertebrates were neglected by biologists, in favor of big vertebrates and "useful" or charismatic species . Invertebrate biology
4200-569: The Axe, Brue , Cary, Parrett, Sheppey , Tone and Yeo . These both feed and drain the flat levels and moors of mid and west Somerset. In the north of the county the River Chew flows into the Bristol Avon . The Parrett is tidal almost to Langport , where there is evidence of two Roman wharfs. At the same site during the reign of King Charles I , river tolls were levied on boats to pay for
4305-624: The Mendips, covers a smaller geographical area than the Somerset Levels; and forms a coastal area around Avonmouth . It too was reclaimed by draining. It is mirrored, across the Severn Estuary , in Wales, by a similar low-lying area: the Caldicot and Wentloog Levels . In the far west of the county, running into Devon, is Exmoor , a high Devonian sandstone moor , which was designated as
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4410-507: The Parrett near Dunball wharf. Construction of the channel, together with improvements to the King's Sedgemoor Drain and the rebuilding of the clyce at Dunball, to create a freshwater seal which prevents saltwater entering the drain from the river, cost £1.4 million. The scheme was first proposed in 1961, following serious flooding in October 1960, when some 78 square miles (200 km) of
4515-680: The Quarter Sessions held at Wells in that year decided that a room should be provided "for the safe keeping of the records of the Sessions". As of 2024 , following the 2023 Periodic Review of Westminster constituencies , the ceremonial county of Somerset is divided into 11 parliamentary constituencies , each returning one Member of Parliament (MP) to the House of Commons . Conservative Labour Liberal Democrat From 1984 to 1994, Somerset
4620-493: The Severn Estuary. In the mid and north of the county the coastline is low as the level wetlands of the levels meet the sea. In the west, the coastline is high and dramatic where the plateau of Exmoor meets the sea, with high cliffs and waterfalls. Along with the rest of South West England , Somerset has a temperate climate which is generally wetter and milder than the rest of the country. The annual mean temperature
4725-451: The Somerset levels were inundated. A channel with a proposed capacity of 1,060 cubic feet per second (30 m/s) was proposed, but arguments about the cost of such a scheme resulted in the capacity being lowered to 600 cubic feet per second (17 m/s). However, the bridges and sluices were either built to cope with the larger flow rates, or made so that they could be easily altered, if funding became available. Construction began in 1969 and
4830-680: The Sowy River and Langacre Rhyne were unable to cope with the volume of water. After water levels subsided a little, the road remained closed as pumps were placed on it to drain the surrounding land. The road reopened in March, but was closed again in September as flood prevention work began. A trench was cut through the road to the east of the existing culvert for the Langacre Rhyne, where new culverts were to be constructed. In order to keep
4935-543: The Sowy River. The culverts and the reconstruction of the road over the top of them was funded by the Department for Transport, and the road reopened in July 2015. The next phase of the project was managed by the recently-formed Somerset Rivers Authority, and involved re-routing the Langacre Rhyne and the Sowy River through the new culverts. The work included the construction of foundation slabs for two tilting weirs, and this
5040-538: The air sacs in their abdomen, are able to control the flow of air through their body. In some aquatic insects, the tracheae exchange gas through the body wall directly, in the form of a gill , or function essentially as normal, via a plastron . Despite being internal, the tracheae of arthropods are shed during moulting ( ecdysis ). Only vertebrate animals have ears, though many invertebrates detect sound using other kinds of sense organs. In insects, tympanal organs are used to hear distant sounds. They are located either on
5145-460: The body can have only one pair of spiracles, each of which connects to an atrium and has a relatively large tracheal tube behind it. The tracheae are invaginations of the cuticular exoskeleton that branch ( anastomose ) throughout the body with diameters from only a few micrometres up to 0.8 mm. The smallest tubes, tracheoles, penetrate cells and serve as sites of diffusion for water , oxygen , and carbon dioxide . Gas may be conducted through
5250-754: The boundaries of the West Saxon kingdom far enough west to include Somerset. The Saxon royal palace in Cheddar was used several times in the 10th century to host the Witenagemot . The nature of the relations between the Britons and the Saxons in Somerset is not entirely clear. Ine's laws demonstrate that the Britons were considered to be a significant enough population in Wessex to merit provisions; however,
5355-941: The call of her host, a male cricket. Depending on where the song of the cricket is coming from, the fly's hearing organs will reverberate at slightly different frequencies. This difference may be as little as 50 billionths of a second, but it is enough to allow the fly to home in directly on a singing male cricket and parasitise it. Like vertebrates, most invertebrates reproduce at least partly through sexual reproduction . They produce specialized reproductive cells that undergo meiosis to produce smaller, motile spermatozoa or larger, non-motile ova . These fuse to form zygotes , which develop into new individuals. Others are capable of asexual reproduction, or sometimes, both methods of reproduction. Extensive research with model invertebrate species such as Drosophila melanogaster and Caenorhabditis elegans has contributed much to our understanding of meiosis and reproduction. However, beyond
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#17327765184755460-448: The channel on the right bank. In one place, a backwater was created, up to 20 feet (6 m) wide, leaving an island some 16 feet (5 m) wide between the new channel and the old one. Where widening was carried out, the new channel included a shelf 1 foot (0.3 m) below the normal summer water level, to increase the range of habitats available. The scheme is not expected to completely prevent flooding of Middle Moor and Aller Moor, but
5565-705: The common presence of trochophore larvae, but the annelids were considered closer to the arthropods because they are both segmented. Now, this is generally considered convergent evolution , owing to many morphological and genetic differences between the two phyla. Among lesser phyla of invertebrates are the Hemichordata , or acorn worms, and the Chaetognatha, or arrow worms. Other phyla include Acoelomorpha , Brachiopoda , Bryozoa , Entoprocta , Phoronida , and Xenoturbellida . Invertebrates can be classified into several main categories, some of which are taxonomically obsolescent or debatable, but still used as terms of convenience. Each however appears in its own article at
5670-506: The conclusion that in vertebrates are a group that deviates from the normal, vertebrates. This has been said to be because researchers in the past, such as Lamarck, viewed vertebrates as a "standard": in Lamarck's theory of evolution, he believed that characteristics acquired through the evolutionary process involved not only survival, but also progression toward a "higher form", to which humans and vertebrates were closer than invertebrates were. Although goal-directed evolution has been abandoned,
5775-453: The counties of Gloucester and Somerset ... and that it should be a county by itself ". The present-day northern border of Somerset (adjoining the counties of Bristol and Gloucestershire) runs along the southern bank of the Avon from the Bristol Channel, then follows around the southern edge of the Bristol built-up area, before continuing upstream along the Avon and then diverges from the river to include Bath and its historic hinterland to
5880-424: The county are the Avon , which flows through Bath and then Bristol, and the Axe , Brue , and Parrett , which drain the Levels. There is evidence of Paleolithic human occupation in Somerset, and the area was subsequently settled by the Celts , Romans and Anglo-Saxons . The county played a significant part in Alfred the Great 's rise to power, and later the English Civil War and the Monmouth Rebellion . In
5985-399: The county. The county contains several-miles-wide sections of the Avon green belt area, which is primarily in place to prevent urban sprawl from the Bristol and Bath built up areas encroaching into the rural areas of North Somerset, Bath and North East Somerset, and Mendip districts in the county, as well as maintaining surrounding countryside. It stretches from the coastline between
6090-490: The crown, with fortifications such as Dunster Castle used for control and defence. Somerset came under the political influence of several different nobles during the Middle Ages. During the Wars of the Roses, an important magnate was Humphrey Stafford, earl of Devon whose wider influence stretched from Cornwall to Wiltshire. After 1485, one of the county's most influential figures was Henry VII's chamberlain Giles Daubeney . Somerset contains HM Prison Shepton Mallet , which
6195-566: The described animal species in the world are invertebrates. The trait that is common to all invertebrates is the absence of a vertebral column (backbone): this creates a distinction between invertebrates and vertebrates. The distinction is one of convenience only; it is not based on any clear biologically homologous trait, any more than the common trait of having wings functionally unites insects, bats, and birds, or than not having wings unites tortoises , snails and sponges . Being animals, invertebrates are heterotrophs, and require sustenance in
6300-466: The distinction of invertebrates and vertebrates persists to this day, even though the grouping has been noted to be "hardly natural or even very sharp." Another reason cited for this continued distinction is that Lamarck created a precedent through his classifications which is now difficult to escape from. It is also possible that some humans believe that, they themselves being vertebrates, the group deserves more attention than invertebrates. In any event, in
6405-457: The few model systems, the modes of reproduction found in invertebrates show incredible diversity. In one extreme example, it is estimated that 10% of orbatid mite species have persisted without sexual reproduction and have reproduced asexually for more than 400 million years. Social behavior is widespread in invertebrates, including cockroaches, termites, aphids, thrips , ants, bees, Passalidae , Acari , spiders, and more. Social interaction
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#17327765184756510-479: The figure at 97%. Many invertebrate taxa have a greater number and diversity of species than the entire subphylum of Vertebrata. Invertebrates vary widely in size, from 10 μm (0.0004 in) myxozoans to the 9–10 m (30–33 ft) colossal squid . Some so-called invertebrates, such as the Tunicata and Cephalochordata , are actually sister chordate subphyla to Vertebrata, being more closely related to vertebrates than to other invertebrates. This makes
6615-402: The following links. The earliest animal fossils appear to be those of invertebrates. 665-million-year-old fossils in the Trezona Formation at Trezona Bore, West Central Flinders, South Australia have been interpreted as being early sponges. Some paleontologists suggest that animals appeared much earlier, possibly as early as 1 billion years ago though they probably became multicellular in
6720-500: The form of the consumption of other organisms. With a few exceptions, such as the Porifera , invertebrates generally have bodies composed of differentiated tissues. There is also typically a digestive chamber with one or two openings to the exterior. The body plans of most multicellular organisms exhibit some form of symmetry , whether radial, bilateral, or spherical. A minority, however, exhibit no symmetry. One example of asymmetric invertebrates includes all gastropod species. This
6825-407: The frequency and severity of such flooding is expected to be significantly reduced as a result of the work. The Environment Agency measure water quality of the river systems in England. Each is given an overall ecological status, which may be one of five levels: high, good, moderate, poor and bad. There are several components that are used to determine this, including biological status, which looks at
6930-436: The hardened exoskeleton. The Nematoda , or roundworms, are perhaps the second largest animal phylum, and are also invertebrates. Roundworms are typically microscopic, and occur in nearly every environment where there is water. A number are important parasites. Smaller phyla related to them are the Kinorhyncha , Priapulida , and Loricifera . These groups have a reduced coelom, called a pseudocoelom. Other invertebrates include
7035-474: The head or elsewhere, depending on the insect family . The tympanal organs of some insects are extremely sensitive, offering acute hearing beyond that of most other animals. The female cricket fly Ormia ochracea has tympanal organs on each side of her abdomen. They are connected by a thin bridge of exoskeleton and they function like a tiny pair of eardrums, but, because they are linked, they provide acute directional information. The fly uses her "ears" to detect
7140-414: The landscape of Somerset falls into types determined by the underlying geology. These landscapes are the limestone karst and lias of the north, the clay vales and wetlands of the centre, the oolites of the east and south, and the Devonian sandstone of the west. To the north-east of the Somerset Levels, the Mendip Hills are moderately high limestone hills. The central and western Mendip Hills
7245-446: The late 19th century; this was taken by the West Somerset Mineral Railway to Watchet Harbour for shipment to the furnaces at Ebbw Vale . Many Somerset soldiers died during the First World War , with the Somerset Light Infantry suffering nearly 5,000 casualties. War memorials were put up in most of the county's towns and villages; only nine, described as the Thankful Villages , had none of their residents killed. During
7350-614: The later medieval period its wealth allowed its monasteries and parish churches to be rebuilt in grand style; Glastonbury Abbey was particularly important, and claimed to house the tomb of King Arthur and Guinevere . The city of Bath is famous for its Georgian architecture, and is a UNESCO World Heritage Site . The county is also the location of Glastonbury Festival , one of the UK's major music festivals. Somerset's name derives from Old English Sumorsǣte , short for Sumortūnsǣte , meaning "the people living at or dependent on Sumortūn ( Somerton )". The first known use of Somersæte
7455-408: The laws also suggest that Britons could not attain the same social standing as the Saxons, and that many were slaves. In light of such policies, many Britons might have chosen to emigrate to places such as Brittany while those who remained would have had incentives to adopt Anglo-Saxon culture. After the Norman Conquest , the county was divided into 700 fiefs , and large areas were owned by
7560-423: The lightest winds. The predominant wind direction is from the south-west. The ceremonial county of Somerset is currently governed by three unitary authorities : Bath and North East Somerset Council (B&NES), North Somerset Council , and Somerset Council . B&NES is also part of the West of England Combined Authority . Modern local government in Somerset began in 1889, when an administrative county
7665-519: The maintenance of the bridge. The Somerset Levels (or Somerset Levels and Moors as they are less commonly but more correctly known) are a sparsely populated wetland area of central Somerset, between the Quantock and Mendip hills. They consist of marine clay levels along the coast, and the inland (often peat based) moors. The Levels are divided into two by the Polden Hills . Land to the south
7770-507: The nighttime geometry of "blacked out" streets, railway lines, and Bristol Temple Meads railway station , to encourage German bombers away from these targets. One, on the German radio navigation beam flight path to Bristol, was constructed on Beacon Batch . It was laid out by Shepperton Studios , based on aerial photographs of the city's railway marshalling yards . The decoys were fitted with dim red lights, simulating activities such as
7875-619: The north of the Avon, before meeting Wiltshire at the Three Shire Stones on the Fosse Way at Batheaston . Somerton took over from Ilchester as the county town in the late thirteenth century, but it declined in importance and the status of county town transferred to Taunton about 1366. The county has two cities , Bath and Wells , and 30 towns (including the county town of Taunton, which has no town council but instead
7980-537: The north, where the River Avon formed the border with Gloucestershire, except that the hundred of Bath Forum , which straddles the Avon, formed part of Somerset. Bristol began as a town on the Gloucestershire side of the Avon, but as it grew it extended across the river into Somerset. In 1373 Edward III proclaimed "that the town of Bristol with its suburbs and precincts shall henceforth be separate from
8085-456: The northern border of Somerset. The Bristol Channel has the second largest tidal range in the world. At Burnham-on-Sea , for example, the tidal range of a spring tide is more than 12 metres (39 feet). Proposals for the construction of a Severn Barrage aim to harness this energy. The island of Steep Holm in the Bristol Channel is within the ceremonial county and is now administered by North Somerset Council. The main coastal towns are, from
8190-529: The notochord would be a less fundamental criterion than aspects of embryological development and symmetry or perhaps bauplan . Despite this, the concept of invertebrates as a taxon of animals has persisted for over a century among the laity , and within the zoological community and in its literature it remains in use as a term of convenience for animals that are not members of the Vertebrata. The following text reflects earlier scientific understanding of
8295-563: The original two groups into ten, by splitting Arachnida and Crustacea from the Linnean Insecta, and Mollusca, Annelida, Cirripedia , Radiata , Coelenterata and Infusoria from the Linnean Vermes. They are now classified into over 30 phyla , from simple organisms such as sea sponges and flatworms to complex animals such as arthropods and molluscs. Invertebrates are animals without a vertebral column. This has led to
8400-422: The other. If a male fiddler loses its large claw, it will grow another on the opposite side after moulting . Sessile animals such as sponges are asymmetrical alongside coral colonies (with the exception of the individual polyps that exhibit radial symmetry); Alpheidae claws that lack pincers; and some copepods , polyopisthocotyleans , and monogeneans which parasitize by attachment or residency within
8505-510: The presence of polybrominated diphenyl ethers (PBDE) and mercury compounds, neither of which had previously been included in the assessment. [REDACTED] Media related to Sowy River at Wikimedia Commons Somerset Somerset ( / ˈ s ʌ m ər s ɪ t , - s ɛ t / SUM -ər-sit , -set ), archaically Somersetshire ( / ˈ s ʌ m ər s ɪ t . ʃ ɪər , - s ɛ t -, - ʃ ər / SUM -ər-sit-sheer , -set- , -shər )
8610-464: The quantity and varieties of invertebrates , angiosperms and fish. Chemical status, which compares the concentrations of various chemicals against known safe concentrations, is rated good or fail. The Sowy River and the King's Sedgemoor Drain are assessed as a single unit, and water quality was as follows in 2019. Like many waterways in the UK, the chemical status changed from good to fail in 2019, due to
8715-467: The rainfall in autumn and winter is caused by the Atlantic depressions, which is when they are most active. In summer, a large proportion of the rainfall is caused by sun heating the ground leading to convection and to showers and thunderstorms. Average rainfall is around 700 mm (28 in). About 8–15 days of snowfall is typical. November to March have the highest mean wind speeds, and June to August
8820-441: The respiratory system by means of active ventilation or passive diffusion. Unlike vertebrates, insects do not generally carry oxygen in their haemolymph . A tracheal tube may contain ridge-like circumferential rings of taenidia in various geometries such as loops or helices . In the head , thorax , or abdomen , tracheae may also be connected to air sacs. Many insects, such as grasshoppers and bees , which actively pump
8925-474: The river under the A372 road at Beer Wall were constructed, and a three-year project to raise the banks and widen the channel to increase its capacity was undertaken. The Sowy River is a 7.5-mile (12.1 km) embanked channel which starts at Monks Leaze clyce below Langport , and carries excess water from the River Parrett to the King's Sedgemoor Drain , from where it flows to the estuary by gravity, rejoining
9030-538: The rivers Frome and Avon, and names of hills. For example, an Anglo-Saxon charter of 682 refers to Creechborough Hill as "the hill the British call Cructan and the Anglo-Saxons call Crychbeorh ". Some modern names are wholly Brittonic in origin, like Tarnock , Priddy , and Chard , while others have both Saxon and Brittonic elements, such as Pen Hill . The caves of the Mendip Hills were settled during
9135-404: The road open during the winter, two temporary bridges were installed, one to carry the road and another for pedestrians. The road bridge, with a span of 52 feet (16 m), was placed in position in just three hours, and remained in use for 26 weeks. Four new culverts were built, each 9.8 by 6.9 feet (3.0 by 2.1 m), two to carry the realigned Langacre Rhyne, and two to carry part of the flow of
9240-453: The stoking of steam locomotives . Burning bales of straw soaked in creosote were used to simulate the effects of incendiary bombs dropped by the first wave of Pathfinder night bombers; meanwhile, incendiary bombs dropped on the correct location were quickly smothered, wherever possible. Drums of oil were also ignited to simulate the effect of a blazing city or town, with the aim of fooling subsequent waves of bombers into dropping their bombs on
9345-511: The term "invertebrates" rather polyphyletic , so the term has little meaning in taxonomy . The word "invertebrate" comes from the Latin word vertebra , which means a joint in general, and sometimes specifically a joint from the spinal column of a vertebrate. The jointed aspect of vertebra is derived from the concept of turning, expressed in the root verto or vorto , to turn. The prefix in- means "not" or "without". The term invertebrates
9450-411: The term and of those animals which have constituted it. According to this understanding, invertebrates do not possess a skeleton of bone, either internal or external. They include hugely varied body plans . Many have fluid-filled, hydrostatic skeletons, like jellyfish or worms. Others have hard exoskeletons , outer shells like those of insects and crustaceans . The most familiar invertebrates include
9555-673: The towns of Portishead and Clevedon , extending eastwards past Nailsea , around the Bristol conurbation, and through to the city of Bath. The green belt border intersects with the Mendip Hills Area of Outstanding Natural Beauty (AONB) along its south boundary, and meets the Cotswolds AONB by its eastern extent along the Wiltshire county border, creating an extended area protected from inappropriate development. Much of
9660-412: The two districts and non-metropolitan county became part of the new ceremonial county of Somerset. On 1 September 2019 the non-metropolitan districts of West Somerset and Taunton Deane merged, with the new district being called Somerset West and Taunton . In 2023, the non-metropolitan county was reorganised by abolishing the four districts and their councils and reconstituting Somerset County Council as
9765-427: The water is drained away to enable the land to be used as pasture during the summer. The scheme is also used to encourage water birds. In January 2010, when bird numbers were at their peak, some 4,000 wigeon, lapwing and teal were recorded on the moor, while other species sighted included Bewick's swan, pintail, shoveler, golden plover and gadwall. In January 2014, the A372 road at Beer Wall flooded, as culverts carrying
9870-412: The west to the north-east, Minehead , Watchet, Burnham-on-Sea, Weston-super-Mare, Clevedon and Portishead . The coastal area between Minehead and the eastern extreme of the administrative county's coastline at Brean Down is known as Bridgwater Bay , and is a National Nature Reserve . North of that, the coast forms Weston Bay and Sand Bay whose northern tip, Sand Point , marks the lower limit of
9975-487: The width of the channel on the right bank. Between Graylake Bridge and the King's Sedgemoor Drain, similar work was undertaken, but only the left bank needed raising, and widening took place on the right bank. Finally, the capacity of the King's Sedgemoor Drain between the Sowy outfall and Parchey Bridge was increased to 950 cubic feet per second (27 m/s) by raising of both banks by up to 1.6 feet (0.5 m), and by widening
10080-496: The wrong location. The Chew Magna decoy town was hit by half a dozen bombs on 2 December 1940, and over a thousand incendiaries on 3 January 1941. The following night the Uphill decoy town, protecting the airfield at Weston-super-Mare , was bombed; a herd of dairy cows was hit, killing some and severely injuring others. The boundaries of Somerset are largely unaltered from medieval times. The main change has been in
10185-644: Was England's oldest prison still in use prior to its closure in 2013, having opened in 1610. During the English Civil War , Somerset was largely Parliamentarian , with key engagements being the Sieges of Taunton and the Battle of Langport . In 1685, the Monmouth Rebellion was played out in Somerset and neighbouring Dorset. The rebels landed at Lyme Regis and travelled north, hoping to capture Bristol and Bath, but they were defeated in
10290-534: Was completed in 1972. The scheme resulted in less flooding on Aller Moor. During 2009 and 2010 work was undertaken to upgrade sluice gates, watercourses and culverts to enable seasonal flooding of Southlake Moor during the winter diverting water from the Sowy River onto the moor. It has the capacity to hold 1.2 million cubic metres as part of a scheme by the Parrett Internal Drainage Board to restore ten floodplains in Somerset. In spring
10395-414: Was created and Somerset County Council was established; Bath was administered separately as a county borough . In 1974, the county and council were abolished and replaced by two two-tier non-metropolitan counties , Somerset and Avon . Somerset was governed by a reconstituted county council and five districts : Mendip , Sedgemoor , South Somerset , Taunton Deane and West Somerset . Taunton Deane
10500-497: Was designated an Area of Outstanding Natural Beauty in 1972 and covers 198 km (76 sq mi). The main habitat on these hills is calcareous grassland , with some arable agriculture. To the south-west of the Somerset Levels are the Quantock Hills which was England's first Area of Outstanding Natural Beauty designated in 1956 which is covered in heathland, oak woodlands, ancient parklands with plantations of conifer and covers 99 square kilometres. The Somerset Coalfield
10605-765: Was drained, much of the land was under a shallow brackish sea in winter and was marsh land in summer. Drainage began with the Romans, and was restarted at various times: by the Anglo-Saxons ; in the Middle Ages by the Glastonbury Abbey , during 1400–1770; and during the Second World War, with the construction of the Huntspill River . Pumping and management of water levels still continues. The North Somerset Levels basin, north of
10710-601: Was funded by the Heart of the South West Local Enterprise Partnership. Beginning in April 2016, the two tilting weirs were built, and a bank to maintain the separation between the Sowy River and the new course of the Langacre Rhyne was constructed. This was the start of a three-year project to increase the capacity of the Sowy River and King's Sedgemoor Drain. While the Sowy River in theory had
10815-461: Was granted borough status that same year. Avon consisted of six districts, of which three were created from areas formerly part of Somerset: Woodspring , Wansdyke , and Bath . In 1996, Avon was abolished and its districts were renamed and reorganised into unitary authorities . Woodspring was renamed 'North Somerset' and Wansydyke and Bath were abolished and a new district covering the same area created, named 'Bath and North East Somerset'. In 1997
10920-410: Was not a major field of study until the work of Linnaeus and Lamarck in the 18th century. During the 20th century, invertebrate zoology became one of the major fields of natural sciences, with prominent discoveries in the fields of medicine, genetics, palaeontology, and ecology. The study of invertebrates has also benefited law enforcement, as arthropods, and especially insects, were discovered to be
11025-430: Was represented by Conservative Margaret Daly as part of the Somerset and Dorset West constituency for elections to the European Parliament . From 1994 to 1999, Somerset was represented by Liberal Democrat Graham Watson as part of the Somerset and North Devon constituency for elections to the European Parliament . From 1999 to 2020, Somerset was part of the South West England constituency for elections to
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