Invertebrates are animals that neither possess nor develop a vertebral column, derived from the notochord. This includes all animals apart from the subphylum Vertebrata. Familiar examples of invertebrates include arthropods, mollusks and cnidarians; the majority of animal species are invertebrates. Many invertebrate taxa have a greater number and variety of species than the entire subphylum of Vertebrata. Invertebrates vary in size, from 50 μm rotifers to the 9–10 m colossal squid; some so-called invertebrates, such as the Tunicata and Cephalochordata are more related to vertebrates than to other invertebrates. This makes the invertebrates paraphyletic, so the term has little meaning in taxonomy; the word "invertebrate" comes from the Latin word vertebra, which means a joint in general, sometimes 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 is not always precise among non-biologists since it does not describe a taxon in the same way that Arthropoda, Vertebrata or Manidae do. Each of these terms describes a valid taxon, subphylum or family. "Invertebrata" is a term of convenience, not a taxon. The Vertebrata as a subphylum comprises such 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 the notochord would be a less fundamental criterion than aspects of embryological development and symmetry or bauplan. Despite this, the concept of invertebrates as a taxon of animals has persisted for over a century among the laity, 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 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 like jellyfish or worms. Others have outer shells like those of insects and crustaceans; the most familiar invertebrates include the Protozoa, Coelenterata, Nematoda, Echinodermata and Arthropoda. Arthropoda include insects 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. Othersjellyfish, sponges; the IUCN estimates that 66,178 extant vertebrate species have been described, which means that over 95% of the described animal species in the world are invertebrates. The trait, common to all invertebrates is the absence of a vertebral column: this creates a distinction between invertebrates and vertebrates.

The distinction is one of convenience only. Being animals, invertebrates are heterotrophs, require sustenance in the form of the consumption of other organisms. With a few exceptions, such as the Porifera, invertebrates have bodies composed of differentiated tissues. There is 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, exhibit no symmetry. One example of asymmetric invertebrates includes all gastropod species; this is seen in snails and sea snails, which have helical shells. Slugs appear externally symmetrical. 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 hermit crabs, they have one claw much larger than 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. 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 tissue trauma. Neuron

Melina Merkouri Indoor Hall, or Rethymno Municipal Indoor Hall, is an indoor sporting arena, located in the city of Rethymno, on the Greek island of Crete. The seating capacity of the arena for basketball games is 1,600 people; the arena is owned by the municipality of Rethymno. The arena is named after politician, Melina Mercouri; the hall was opened in the year 1992. The arena has been used as the home arena of the Greek professional basketball team Rethymno Cretan Kings, of the Greek Basket League. In recent years, the arena's seating capacity was increased from 1,100 to 1,600; this was done because of the fact that Rethymno was going to compete in the top-tier level Greek Basket League, for the first time, during the Greek League 2007–08 season. The final phase of the 2007 FIBA Europe Under-16 Championship was held at the arena; the arena hosted the 2017 FIBA Europe Under-20 Championship. There are plans to further expand the arena again, in the near future. Information on the arena @ Stadia.gr

Mehmet Osman is a fictional character from the BBC soap opera EastEnders, played by Haluk Bilginer. Mehmet is portrayed as a charmer, rogue and a serial womaniser, makes recurring appearances in EastEnders from 1985 to 1987, regularly until 1989. Mehmet is a Turkish Cypriot and the older brother of the original owner of the Bridge street café, Ali Osman, he is first seen in Albert Square in June 1985 when he takes part in one of Ali's regular late-night poker games. Like his brother, Mehmet is a serial gambler and whenever he gambles the stakes are foolishly high. Unlike his brother, Mehmet doesn't live in Stoke Newington. In June 1986 Mehmet and Ali start a cab firm called'OzCabs' from a corner table in Ali's Café. Mehmet is married with three children, but monogamy is one sanctity of marriage that he is more than willing to overlook; that month punk Mary Smith catches his eye, so he bets his sceptical brother £10 that he can get Mary to have sex with him. Mary is well aware that Mehmet's intentions are dishonourable and refuses to have sex with him, but Mehmet persists and she relents and spends the night with him.

A triumphant Mehmet collects his winnings and gloats to his brother in the café. However, Mary overhears their entire conversation and she sets about trying to get revenge on him by hoax calling his cab-firm and vandalising his car. In the year Mehmet acts as Pat Wicks's pimp, setting her up with clients on a regular basis and he persuades Pat to convince Mary to go prostitute herself too, he gets involved in Kathy Beale's Knitting business conning her and disappearing with all her profits. After he gets into more trouble with his customers for overcharging on fares and trying to seduce Hannah Carpenter — the wife of his employee — the residents of Albert Square decide to confront him. Den Watts, Pete Beale and Tony Carpenter find him and give him a severe beating which involves having his arms pinned behind his back whilst taking a number of blows to the stomach. Mehmet proceeds to make things infinitely worse for himself soon after, when he stakes his house and business on a bet and swiftly disappears leaving his wife, Guizin Osman, to face up to the consequences.

A homeless Guzin arrives at Ali and his wife Sue's doorstep with the news that Mehmet had beaten her, she isn't returning to him. Ali and Sue are forced to take Guizin and her three children, Murat and Emine into their one bedroom apartment. Mehmet returns to Walford in May 1987 and he manages to persuade his long suffering wife to give their marriage another chance. However, his promises to Guizin prove to be hollow as soon after he decides that the barmaid Donna Ludlow is to be the next sexual conquest. Donna refuses his advances, but can't resist informing Guizin about his offer and Guizin and Donna nearly fight on New Year's Eve that year. Guizin and Mehmet's marriage is turbulent and they are always involved in intense arguments concerning money and gambling. In 1988 Mehmet and Guzin become partners in Ali's café after Sue gives up working to look after her baby. Mehmet clashes with his wife about the amount of time he takes off to gamble and the way the café is run. In the year Mehmet and Ali run up huge gambling debts to Joanne Francis, manageress of Strokes wine bar, and, a member of the criminal underworld known as The Firm.

Desperate for money the two turn to Ian Beale, for a loan. He agrees, but charges his employers 10 percent interest and when they cannot meet the repayments, he demands a stake in the café; the brothers refuse, but the debt leads to Ali losing the café to Ian the following year. Mehmet's marriage goes through some more trouble in 1989, when Ali's wife, discovers that her husband had been having sex with prostitute, Donna Ludlow. Sue turns to Mehmet for comfort. Seeing her chance for revenge Sue makes a pass at Mehmet, purposefully kissing him in Ali's view. For once Mehmet is innocent, but Ali refuses to believe this and the brothers have a massive fight. Ali divulges Sue and Mehmet's fabricated affair to Guzin, unable to forgive her husband's latest infidelity with her sister-in-law. After viciously attacking Mehmet she leaves Walford to return to Northern Cyprus, taking their three children with her. After another huge argument with Sue, Mehmet decides to return to Northern Cyprus in order to win his wife back.

His last appearance is in March 1989. Mehmet Osman was conceptualised by the creators of Tony Holland and Julia Smith. Mehmet, the brother of original character Ali Osman, was part of a well-intentioned attempt to represent the proportion of Turkish Cypriots who had immigrated to England and settled in the East End of London. Holland and Smith knew that for the soap to succeed there needed to be a varied group of characters, so that several different sections of the audience had someone to identify with. Additionally, if the programme was to be realistic, it had to reflect the cross-section of society that existed in the real location. For these reasons, different sexes, classes and races were all included in the original character line-up. Both Holland and Smith had been at the forefront of the move towards'integrated casting' in television and had encountered an array of ethnic diversities in the process. Though the ethnic minority groups were deemed the hardest to research and Smith called upon their social contacts to relay information abou