94-433: (see text ) The nematodes ( / ˈ n ɛ m ə t oʊ d z / NEM -ə-tohdz or NEEM - ; ‹See Tfd› Greek : Νηματώδη ; Latin : Nematoda ), roundworms or eelworms constitute the phylum Nematoda . They are a diverse animal phylum inhabiting a broad range of environments. Most species are free-living, feeding on microorganisms , but many species are parasitic . The parasitic worms ( helminths ) are
188-577: A Linear B clay tablet found in Messenia that dates to between 1450 and 1350 BC, making Greek the world's oldest recorded living language . Among the Indo-European languages, its date of earliest written attestation is matched only by the now-extinct Anatolian languages . The Greek language is conventionally divided into the following periods: In the modern era, the Greek language entered
282-577: A basis for coinages: anthropology , photography , telephony , isomer , biomechanics , cinematography , etc. Together with Latin words , they form the foundation of international scientific and technical vocabulary ; for example, all words ending in -logy ('discourse'). There are many English words of Greek origin . Greek is an independent branch of the Indo-European language family. The ancient language most closely related to it may be ancient Macedonian , which, by most accounts,
376-457: A characteristically bent or fan-shaped tail. During copulation , one or more chitinized spicules move out of the cloaca and are inserted into the genital pore of the female. Amoeboid sperm crawl along the spicule into the female worm. Nematode sperm is thought to be the only eukaryotic cell without the globular protein G-actin . Eggs may be embryonated or unembryonated when passed by
470-455: A collaborative wiki called 959 Nematode Genomes is underway to improve the systematics of this phylum. An analysis of the mitochondrial DNA suggests that the following groupings are valid In 2022 a new classification of the entire phylum Nematoda was presented by M. Hodda. It was based on current molecular, developmental and morphological evidence. Under this classification, the following classes and subclasses are presented: Nematode eggs from
564-508: A faster, more convenient cursive writing style with the use of ink and quill . The Greek alphabet consists of 24 letters, each with an uppercase ( majuscule ) and lowercase ( minuscule ) form. The letter sigma has an additional lowercase form (ς) used in the final position of a word: In addition to the letters, the Greek alphabet features a number of diacritical signs : three different accent marks ( acute , grave , and circumflex ), originally denoting different shapes of pitch accent on
658-481: A genetically determined correlation between DNA repair capacity and lifespan. In female C. elegans , germline processes that control DNA repair and formation of chromosomal crossovers during meiosis were shown to progressively deteriorate with age. Different free-living species feed on materials as varied as bacteria , algae , fungi , small animals, fecal matter, dead organisms, and living tissues. Free-living marine nematodes are important and abundant members of
752-533: A glandular and muscular ejaculatory duct associated with the vas deferens and cloaca . In females, the ovaries each open into an oviduct (in hermaphrodites, the eggs enter a spermatheca first) and then a glandular uterus . The uteri both open into a common vulva/vagina, usually located in the middle of the morphologically ventral surface. Reproduction is usually sexual, though hermaphrodites are capable of self-fertilization. Males are usually smaller than females or hermaphrodites (often much smaller) and often have
846-443: A large ventral, a smaller dorsal and two pairs of sublateral cords extend posteriorly. Each nerve lies within a cord of connective tissue lying beneath the cuticle and between the muscle cells. The ventral nerve is the largest, and has a double structure forward of the excretory pore . The dorsal nerve is responsible for motor control, while the lateral nerves are sensory, and the ventral combines both functions. The nervous system
940-590: A lesser extent, in the Western Mediterranean in and around colonies such as Massalia , Monoikos , and Mainake . It was also used as the official language of government and religion in the Christian Nubian kingdoms , for most of their history. Greek, in its modern form, is the official language of Greece, where it is spoken by almost the entire population. It is also the official language of Cyprus (nominally alongside Turkish ) and
1034-400: A limited but productive system of compounding and a rich inflectional system. Although its morphological categories have been fairly stable over time, morphological changes are present throughout, particularly in the nominal and verbal systems. The major change in the nominal morphology since the classical stage was the disuse of the dative case (its functions being largely taken over by
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#17327907484491128-459: A mixed syllable structure, permitting complex syllabic onsets but very restricted codas. It has only oral vowels and a fairly stable set of consonantal contrasts . The main phonological changes occurred during the Hellenistic and Roman period (see Koine Greek phonology for details): In all its stages, the morphology of Greek shows an extensive set of productive derivational affixes ,
1222-500: A pore on the underside of the animal, close to the pharynx. In most other nematodes, these specialized cells have been replaced by an organ consisting of two parallel ducts connected by a single transverse duct. This transverse duct opens into a common canal that runs to the excretory pore. At the anterior end of the animal a dense, circular nerve ring which serves as the brain surrounds the pharynx. From this ring six labial papillary nerve cords extend anteriorly, while six nerve cords;
1316-410: A range of reproductive modes, including sexual reproduction , facultative sexuality (in which most, but not all, generations reproduce asexually), and both meiotic and mitotic parthenogenesis . The genus Mesorhabditis exhibits an unusual form of parthenogenesis, in which sperm-producing males copulate with females, but the sperm do not fuse with the ovum. Contact with the sperm is essential for
1410-455: A series of inhibitors to target digestive and immune-related host proteases , which include pepsin , trypsin , chymotrypsin / elastase , cathepsins , and metallocarboxypeptidases (MCPs). Ascaris species inhibit MCPs by releasing an enzyme known as Ascaris carboxypeptidase inhibitor (ACI). This enzyme binds to the active site of MCP and blocks the cleavage of its own proteins by the host MCP. Similarly, they inhibit trypsin by releasing
1504-460: A state of diglossia : the coexistence of vernacular and archaizing written forms of the language. What came to be known as the Greek language question was a polarization between two competing varieties of Modern Greek: Dimotiki , the vernacular form of Modern Greek proper, and Katharevousa , meaning 'purified', a compromise between Dimotiki and Ancient Greek developed in the early 19th century that
1598-426: A synonym. However, in 1910, Grobben proposed the phylum Aschelminthes and the nematodes were included as class Nematoda along with class Rotifera, class Gastrotricha, class Kinorhyncha, class Priapulida, and class Nematomorpha (The phylum was later revived and modified by Libbie Henrietta Hyman in 1951 as Pseudoceolomata, but remained similar). In 1932, Potts elevated the class Nematoda to the level of phylum, leaving
1692-585: Is Bursaphelenchus xylophilus , the pine wood nematode, present in Asia and America and recently discovered in Europe. This nematode is transmitted from tree to tree by sawyer beetles ( Monochamus ). Greek language Greek ( Modern Greek : Ελληνικά , romanized : Elliniká , [eliniˈka] ; Ancient Greek : Ἑλληνική , romanized : Hellēnikḗ ) is an Indo-European language, constituting an independent Hellenic branch within
1786-460: Is a nematode genus of parasitic worms known as the "small intestinal roundworms". One species, Ascaris lumbricoides , affects humans and causes the disease ascariasis . Another species, Ascaris suum , typically infects pigs . Other ascarid genera infect other animals, such as Parascaris equorum , the equine roundworm, and Toxocara and Toxascaris , which infect dogs and cats. Their eggs are deposited in feces and soil. Plants with
1880-442: Is a lethal parasite of gastropods such as slugs and snails . Some members of the genus Steinernema such as Steinernema carpocapsae and Steinernema riobrave are generalist parasites of webworms , cutworms , armyworms , girdlers , some weevils , wood-borers and corn earworm moths . These organisms are grown commercially as biological pest control agents which can be used as an alternative to pesticides ; their use
1974-531: Is also the only place in the nematode body that contains cilia , which are all nonmotile and with a sensory function. The bodies of nematodes are covered in numerous sensory bristles and papillae that together provide a sense of touch. Behind the sensory bristles on the head lie two small pits, or ' amphids '. These are well supplied with nerve cells and are probably chemoreception organs. A few aquatic nematodes possess what appear to be pigmented eye-spots, but whether or not these are actually sensory in nature
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#17327907484492068-558: Is considered very safe. Plant-parasitic nematodes include several groups causing severe crop losses, taking 10% of crops worldwide every year. The most common genera are Aphelenchoides ( foliar nematodes ), Ditylenchus , Globodera (potato cyst nematodes), Heterodera (soybean cyst nematodes), Longidorus , Meloidogyne ( root-knot nematodes ), Nacobbus , Pratylenchus (lesion nematodes), Trichodorus , and Xiphinema (dagger nematodes). Several phytoparasitic nematode species cause histological damages to roots, including
2162-431: Is long, cylindrical, and fusiform (pointed at both the ends). The body wall is composed of cuticle , epidermis and musculature. There is a pseudocoelom . Respiration is by simple diffusion. The nervous system consists of a nerve ring and many longitudinal nerve cords. Reproduction is exclusively sexual, and males are usually shorter than females. As part of the parasite defense strategy, Ascaris roundworms secrete
2256-459: Is often found at the tip of the tail. The epidermis is either a syncytium or a single layer of cells, and is covered by a thick collagenous cuticle . The cuticle is often of a complex structure and may have two or three distinct layers. Underneath the epidermis lies a layer of longitudinal muscle cells. The relatively rigid cuticle works with the muscles to create a hydroskeleton, as nematodes lack circumferential muscles. Projections run from
2350-446: Is often ornamented with ridges, rings, bristles, or other distinctive structures. The head of a nematode is relatively distinct. Whereas the rest of the body is bilaterally symmetrical, the head is radially symmetrical, with sensory bristles and, in many cases, solid 'head-shields' radiating outwards around the mouth. The mouth has either three or six lips, which often bear a series of teeth on their inner edges. An adhesive 'caudal gland'
2444-402: Is present, with the pharynx connecting directly to a muscleless intestine that forms the main length of the gut. This produces further enzymes and also absorbs nutrients through its single-cell-thick lining. The last portion of the intestine is lined by a cuticle, forming a rectum , which expels waste through the anus just below and in front of the tip of the tail. The movement of food through
2538-820: Is sometimes called aljamiado , as when Romance languages are written in the Arabic alphabet. Article 1 of the Universal Declaration of Human Rights in Greek: Transcription of the example text into Latin alphabet : Article 1 of the Universal Declaration of Human Rights in English: Proto-Greek Mycenaean Ancient Koine Medieval Modern Ascaris Ascaris
2632-763: Is still used internationally for the writing of Ancient Greek . In Greek, the question mark is written as the English semicolon, while the functions of the colon and semicolon are performed by a raised point (•), known as the ano teleia ( άνω τελεία ). In Greek the comma also functions as a silent letter in a handful of Greek words, principally distinguishing ό,τι ( ó,ti , 'whatever') from ότι ( óti , 'that'). Ancient Greek texts often used scriptio continua ('continuous writing'), which means that ancient authors and scribes would write word after word with no spaces or punctuation between words to differentiate or mark boundaries. Boustrophedon , or bi-directional text,
2726-632: Is to modern spoken English ". Greek is spoken today by at least 13 million people, principally in Greece and Cyprus along with a sizable Greek-speaking minority in Albania near the Greek-Albanian border. A significant percentage of Albania's population has knowledge of the Greek language due in part to the Albanian wave of immigration to Greece in the 1980s and '90s and the Greek community in
2820-454: Is unclear. Most nematode species are dioecious , with separate male and female individuals, though some, such as Caenorhabditis elegans , are androdioecious , consisting of hermaphrodites and rare males. Both sexes possess one or two tubular gonads . In males, the sperm are produced at the end of the gonad and migrate along its length as they mature. The testis opens into a relatively wide seminal vesicle and then during intercourse into
2914-562: The British Overseas Territory of Akrotiri and Dhekelia (alongside English ). Because of the membership of Greece and Cyprus in the European Union, Greek is one of the organization's 24 official languages . Greek is recognized as a minority language in Albania, and used co-officially in some of its municipalities, in the districts of Gjirokastër and Sarandë . It is also an official minority language in
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3008-657: The European canon . Greek is also the language in which many of the foundational texts in science and philosophy were originally composed. The New Testament of the Christian Bible was also originally written in Greek. Together with the Latin texts and traditions of the Roman world , the Greek texts and Greek societies of antiquity constitute the objects of study of the discipline of Classics . During antiquity , Greek
3102-516: The Indo-Iranian languages (see Graeco-Aryan ), but little definitive evidence has been found. In addition, Albanian has also been considered somewhat related to Greek and Armenian, and it has been proposed that they all form a higher-order subgroup along with other extinct languages of the ancient Balkans; this higher-order subgroup is usually termed Palaeo-Balkan , and Greek has a central position in it. Linear B , attested as early as
3196-543: The Moltrasio Formation , and the Rhynie chert , where the earliest known fossils are known from. Nematodes are very small, slender worms: typically about 5 to 100 μm thick, and 0.1 to 2.5 mm long. The smallest nematodes are microscopic, while free-living species can reach as much as 5 cm (2 in), and some parasitic species are larger still, reaching over 1 m (3 ft) in length. The body
3290-865: The Monhysterida representing a very ancient minor group of nematodes. Among the Secernentea, the Diplogasteria may need to be united with the Rhabditia , while the Tylenchia might be paraphyletic with the Rhabditia. The understanding of roundworm systematics and phylogeny as of 2002 is summarised below: Phylum Nematoda Later work has suggested the presence of 12 clades. The Secernentea—a group that includes virtually all major animal and plant 'nematode' parasites—apparently arose from within
3384-780: The United Kingdom , and throughout the European Union , especially in Germany . Historically, significant Greek-speaking communities and regions were found throughout the Eastern Mediterranean , in what are today Southern Italy , Turkey , Cyprus , Syria , Lebanon , Israel , Palestine , Egypt , and Libya ; in the area of the Black Sea , in what are today Turkey, Bulgaria , Romania , Ukraine , Russia , Georgia , Armenia , and Azerbaijan ; and, to
3478-537: The Vermes . The name of the group Nematoda, informally called "nematodes", came from Nematoidea , originally defined by Karl Rudolphi (1808), from Ancient Greek νῆμα ( nêma, nêmatos , 'thread') and -ειδἠς ( -eidēs , 'species'). It was treated as family Nematodes by Burmeister (1837). At its origin, the "Nematoidea" erroneously included Nematodes and Nematomorpha , attributed by von Siebold (1843). Along with Acanthocephala , Trematoda , and Cestoidea , it formed
3572-458: The clades Ascaridina, Spirurina, and Trichocephalida have been discovered in coprolites from the Oligocene -aged Tremembé Formation, which represented a palaeolake in present-day São Paulo with a diverse fossil assemblage of birds, fish, and arthropods that lent itself to fostering high nematode diversity. Nematodes have also been found in various lagerstätten , such as Burmese amber ,
3666-468: The genitive ). The verbal system has lost the infinitive , the synthetically -formed future, and perfect tenses and the optative mood . Many have been replaced by periphrastic ( analytical ) forms. Pronouns show distinctions in person (1st, 2nd, and 3rd), number (singular, dual , and plural in the ancient language; singular and plural alone in later stages), and gender (masculine, feminine, and neuter), and decline for case (from six cases in
3760-651: The meiobenthos . They play an important role in the decomposition process, aid in recycling of nutrients in marine environments, and are sensitive to changes in the environment caused by pollution. One roundworm of note, C. elegans , lives in the soil and has found much use as a model organism . C. elegans has had its entire genome sequenced, the developmental fate of every cell determined, and every neuron mapped. Nematodes that commonly parasitise humans include ascarids ( Ascaris ), filarias , hookworms , pinworms ( Enterobius ), and whipworms ( Trichuris trichiura ). The species Trichinella spiralis , commonly known as
3854-417: The syntax of Greek have remained constant: verbs agree with their subject only, the use of the surviving cases is largely intact (nominative for subjects and predicates, accusative for objects of most verbs and many prepositions, genitive for possessors), articles precede nouns, adpositions are largely prepositional, relative clauses follow the noun they modify and relative pronouns are clause-initial. However,
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3948-411: The uterus until they hatch. The juvenile nematodes then ingest the parent nematode. This process is significantly promoted in environments with a low food supply. The nematode model species C. elegans , C. briggsae , and Pristionchus pacificus , among other species, exhibit androdioecy , which is otherwise very rare among animals. The single genus Meloidogyne (root-knot nematodes) exhibits
4042-566: The 20th century on), especially from French and English, are typically not inflected; other modern borrowings are derived from Albanian , South Slavic ( Macedonian / Bulgarian ) and Eastern Romance languages ( Aromanian and Megleno-Romanian ). Greek words have been widely borrowed into other languages, including English. Example words include: mathematics , physics , astronomy , democracy , philosophy , athletics , theatre, rhetoric , baptism , evangelist , etc. Moreover, Greek words and word elements continue to be productive as
4136-563: The Adenophorea were not in a uniform group. Initial studies of incomplete DNA sequences suggested the existence of five clades : The Secernentea seem to be a natural group of close relatives, while the "Adenophorea" appear to be a paraphyletic assemblage of roundworms that retain a good number of ancestral traits . The old Enoplia do not seem to be monophyletic, either, but do contain two distinct lineages. The old group " Chromadoria " seems to be another paraphyletic assemblage, with
4230-457: The Adenophorea. In 2019, a study identified one conserved signature indel (CSI) found exclusively in members of the phylum Nematoda through comparative genetic analyses. The CSI consists of a single amino acid insertion within a conserved region of a Na(+)/H(+) exchange regulatory factor protein NRFL-1 and is a molecular marker that distinguishes the phylum from other species. A major effort by
4324-544: The Greek alphabet since approximately the 9th century BC. It was created by modifying the Phoenician alphabet , with the innovation of adopting certain letters to represent the vowels. The variant of the alphabet in use today is essentially the late Ionic variant, introduced for writing classical Attic in 403 BC. In classical Greek, as in classical Latin, only upper-case letters existed. The lower-case Greek letters were developed much later by medieval scribes to permit
4418-549: The Greek language was the Cypriot syllabary (also a descendant of Linear A via the intermediate Cypro-Minoan syllabary ), which is closely related to Linear B but uses somewhat different syllabic conventions to represent phoneme sequences. The Cypriot syllabary is attested in Cyprus from the 11th century BC until its gradual abandonment in the late Classical period, in favor of the standard Greek alphabet. Greek has been written in
4512-593: The Indo-European language family. It is native to Greece , Cyprus , Italy (in Calabria and Salento ), southern Albania , and other regions of the Balkans , Caucasus , the Black Sea coast, Asia Minor , and the Eastern Mediterranean . It has the longest documented history of any Indo-European language, spanning at least 3,400 years of written records. Its writing system is the Greek alphabet , which has been used for approximately 2,800 years; previously, Greek
4606-602: The Introverta—depending on the validity of the former—are often ranked as a superphylum . For an up-to-date view (as of 2022), see Phylogenomic Analysis of the Phylum Nematoda: Conflicts and Congruences With Morphology, 18S rRNA, and Mitogenomes . Due to the lack of knowledge regarding many nematodes, their systematics is contentious. An early and influential classification was proposed by Chitwood and Chitwood—later revised by Chitwood—who divided
4700-696: The Nematoda has always been considered to be well resolved. Morphological characters and molecular phylogenies agree with placement of the roundworms as a sister taxon to the parasitic Nematomorpha ; together, they make up the Nematoida . Along with the Scalidophora (formerly Cephalorhyncha), the Nematoida form the clade Cycloneuralia , but much disagreement occurs both between and among the available morphological and molecular data. The Cycloneuralia or
4794-404: The acute during the late 20th century, and it has only been retained in typography . After the writing reform of 1982, most diacritics are no longer used. Since then, Greek has been written mostly in the simplified monotonic orthography (or monotonic system), which employs only the acute accent and the diaeresis. The traditional system, now called the polytonic orthography (or polytonic system),
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#17327907484494888-626: The ancestral protostome Hox genotype, which shows that the reduction has occurred within the nematode phylum. Nematode species can be difficult to distinguish from one another. Consequently, estimates of the number of nematode species are uncertain. A 2013 survey of animal biodiversity published in the mega journal Zootaxa puts this figure at over 25,000. Estimates of the total number of extant species are subject to even greater variation. A widely referenced article published in 1993 estimated there may be over 1 million species of nematode. A subsequent publication challenged this claim, estimating
4982-406: The animal can thrust into its prey. In some species, the style is hollow and can be used to suck liquids from plants or animals. The oral cavity opens into a muscular, sucking pharynx , also lined with cuticle. Digestive glands are found in this region of the gut, producing enzymes that start to break down the food. In stylet-bearing species, these may even be injected into the prey. No stomach
5076-479: The arrival of Proto-Greeks, some documented in Mycenaean texts ; they include a large number of Greek toponyms . The form and meaning of many words have changed. Loanwords (words of foreign origin) have entered the language, mainly from Latin, Venetian , and Turkish . During the older periods of Greek, loanwords into Greek acquired Greek inflections, thus leaving only a foreign root word. Modern borrowings (from
5170-463: The bee less active, thus less effective in pollen collection. Depending on its species, a nematode may be beneficial or detrimental to plant health. From agricultural and horticulture perspectives, the two categories of nematodes are the predatory ones, which kill garden pests; and the pest nematodes, which attack plants, or act as vectors spreading plant viruses between crop plants. Predatory nematodes include Phasmarhabditis hermaphrodita which
5264-402: The cause of soil-transmitted helminthiases . They are taxonomically classified along with arthropods , tardigrades and other moulting animals in the clade Ecdysozoa . Unlike the vaguely similar flatworms , nematodes have a tubular digestive system , with openings at both ends. Like tardigrades, they have a reduced number of Hox genes , but their sister phylum Nematomorpha has kept
5358-796: The country. Prior to the Greco-Turkish War and the resulting population exchange in 1923 a very large population of Greek-speakers also existed in Turkey , though very few remain today. A small Greek-speaking community is also found in Bulgaria near the Greek-Bulgarian border. Greek is also spoken worldwide by the sizable Greek diaspora which has notable communities in the United States , Australia , Canada , South Africa , Chile , Brazil , Argentina , Russia , Ukraine ,
5452-441: The dative led to a rise of prepositional indirect objects (and the use of the genitive to directly mark these as well). Ancient Greek tended to be verb-final, but neutral word order in the modern language is VSO or SVO. Modern Greek inherits most of its vocabulary from Ancient Greek, which in turn is an Indo-European language, but also includes a number of borrowings from the languages of the populations that inhabited Greece before
5546-493: The digestive system is the result of the body movements of the worm. The intestine has valves or sphincters at either end to help control food movement through the body. Nitrogenous waste is excreted in the form of ammonia through the body wall, and is not associated with any specific organs. However, the structures for excreting salt to maintain osmoregulation are typically more complex. In many marine nematodes, one or two unicellular ' renette glands ' excrete salt through
5640-528: The earliest forms attested to four in the modern language). Nouns, articles, and adjectives show all the distinctions except for a person. Both attributive and predicative adjectives agree with the noun. The inflectional categories of the Greek verb have likewise remained largely the same over the course of the language's history but with significant changes in the number of distinctions within each category and their morphological expression. Greek verbs have synthetic inflectional forms for: Many aspects of
5734-412: The eggs on them infect any organism that consumes them. A. lumbricoides is the largest intestinal roundworm and is the most common helminth infection of humans worldwide. Infestation can cause morbidity by compromising nutritional status, affecting cognitive processes, inducing tissue reactions such as granuloma to larval stages, and by causing intestinal obstruction , which can be fatal. The body
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#17327907484495828-442: The eggshell is complicated and includes several layers; a detailed anatomical and terminological framework has been proposed for these layers in 2023. Nematodes as a whole possess a wide range of modes of reproduction. Some nematodes, such as Heterorhabditis spp., undergo a process called endotokia matricida : intrauterine birth causing maternal death. Some nematodes are hermaphroditic , and keep their self-fertilized eggs inside
5922-412: The extent that one can speak of a new language emerging. Greek speakers today still tend to regard literary works of ancient Greek as part of their own rather than a foreign language. It is also often stated that the historical changes have been relatively slight compared with some other languages. According to one estimation, " Homeric Greek is probably closer to Demotic than 12-century Middle English
6016-425: The female, meaning their fertilized eggs may not yet be developed. A few species are known to be ovoviviparous . The eggs are protected by an outer shell, secreted by the uterus. In free-living roundworms, the eggs hatch into larvae , which appear essentially identical to the adults, except for an underdeveloped reproductive system; in parasitic roundworms, the lifecycle is often much more complicated. The structure of
6110-473: The figure to be at least 40,000 species. Although the highest estimates (up to 100 million species) have since been deprecated, estimates supported by rarefaction curves , together with the use of DNA barcoding and the increasing acknowledgment of widespread cryptic species among nematodes, have placed the figure closer to 1 million species. Nematodes have successfully adapted to nearly every ecosystem : from marine (salt) to fresh water, soils, from
6204-400: The first used term in case of synonyms. The phylogenetic relationships of the nematodes and their close relatives among the protostomian Metazoa are unresolved. Traditionally, they were held to be a lineage of their own, but in the 1990s, they were proposed to form the group Ecdysozoa together with moulting animals, such as arthropods . The identity of the closest living relatives of
6298-490: The formation of visible galls (e.g. by root-knot nematodes), which are useful characters for their diagnostic in the field. Some nematode species transmit plant viruses through their feeding activity on roots. One of them is Xiphinema index , vector of grapevine fanleaf virus , an important disease of grapes, another one is Xiphinema diversicaudatum , vector of arabis mosaic virus . Other nematodes attack bark and forest trees. The most important representative of this group
6392-472: The genera occur as parasites of vertebrates ; about 35 nematode species occur in humans. The word nematode comes from the Modern Latin compound of nemat- 'thread' (from Greek nema , genitive nematos 'thread', from the stem nein 'to spin'; cf. needle ) + -odes 'like, of the nature of' (cf. -oid ). In 1758, Linnaeus described some nematode genera (e.g., Ascaris ), then included in
6486-449: The infected ants for berries, and eat them. Parasite eggs passed in the bird's feces are subsequently collected by foraging C. atratus and are fed to their larvae , thus completing the lifecycle of M. neotropicum . Similarly, multiple varieties of nematodes have been found in the abdominal cavities of the primitively social sweat bee, Lasioglossum zephyrus . Inside the female body, the nematode hinders ovarian development and renders
6580-417: The inner surface of muscle cells towards the nerve cords ; this is a unique arrangement in the animal kingdom, in which nerve cells normally extend fibers into the muscles rather than vice versa . The oral cavity is lined with cuticles, which are often strengthened with structures, such as ridges, especially in carnivorous species, which may bear several teeth. The mouth often includes a sharp stylet , which
6674-449: The language show both conservative and innovative tendencies across the entire attestation of the language from the ancient to the modern period. The division into conventional periods is, as with all such periodizations, relatively arbitrary, especially because, in all periods, Ancient Greek has enjoyed high prestige, and the literate borrowed heavily from it. Across its history, the syllabic structure of Greek has varied little: Greek shows
6768-467: The late 15th century BC, was the first script used to write Greek. It is basically a syllabary , which was finally deciphered by Michael Ventris and John Chadwick in the 1950s (its precursor, Linear A , has not been deciphered and most likely encodes a non-Greek language). The language of the Linear B texts, Mycenaean Greek , is the earliest known form of Greek. Another similar system used to write
6862-452: The many other countries of the Greek diaspora . Greek roots have been widely used for centuries and continue to be widely used to coin new words in other languages; Greek and Latin are the predominant sources of international scientific vocabulary . Greek has been spoken in the Balkan peninsula since around the 3rd millennium BC, or possibly earlier. The earliest written evidence is
6956-465: The morphological changes also have their counterparts in the syntax, and there are also significant differences between the syntax of the ancient and that of the modern form of the language . Ancient Greek made great use of participial constructions and of constructions involving the infinitive, and the modern variety lacks the infinitive entirely (employing a raft of new periphrastic constructions instead) and uses participles more restrictively. The loss of
7050-435: The name the same. Despite Potts' classification being equivalent to Cobbs', both names have been used (and are still used today) and Nematode became a popular term in zoological science. Since Cobb was the first to include nematodes in a particular phylum separated from Nematomorpha, some researchers consider the valid taxon name to be Nemates or Nemata, rather than Nematoda, because of the zoological rule that gives priority to
7144-409: The nemas and gordiids was realized by Vejdovsky when he named a group to contain the horsehair worms the order Nematomorpha. In 1919, Nathan Cobb proposed that nematodes should be recognized alone as a phylum. He argued they should be called "nema" in English rather than "nematodes" and defined the taxon Nemates (later emended as Nemata, Latin plural of nema ), listing Nematoidea sensu restricto as
7238-408: The obsolete group Entozoa , created by Rudolphi (1808). They were also classed along with Acanthocephala in the obsolete phylum Nemathelminthes by Gegenbaur (1859). In 1861, K. M. Diesing treated the group as order Nematoda. In 1877, the taxon Nematoidea, including the family Gordiidae (horsehair worms), was promoted to the rank of phylum by Ray Lankester . The first clear distinction between
7332-489: The ovum to begin dividing, but because no fusion of the cells occurs, the male contributes no genetic material to the offspring, which are essentially clones of the female. The nematode Caenorhabditis elegans is often used as a model organism for studying aging at the molecular level. For example, in C. elegans aging negatively impacts DNA repair , and mutants of C. elegans that are long-lived were shown to have increased DNA repair capability. These findings suggest
7426-421: The phylum into two classes— Aphasmidia and Phasmidia . These were later renamed Adenophorea (gland bearers) and Secernentea (secretors), respectively. The Secernentea share several characteristics, including the presence of phasmids , a pair of sensory organs located in the lateral posterior region, and this was used as the basis for this division. This scheme was adhered to in many later classifications, though
7520-503: The polar regions to the tropics, as well as the highest to the lowest of elevations. They are ubiquitous in freshwater, marine, and terrestrial environments, where they often outnumber other animals in both individual and species counts, and are found in locations as diverse as mountains, deserts, and oceanic trenches . They are found in every part of the Earth's lithosphere , even at great depths, 0.9–3.6 km (3,000–12,000 ft) below
7614-584: The protein Ascaris Trypsin Inhibitor ( pdb 1ATA ). Ascaris has been present in humans for at least several thousand years, as evidenced by Ascaris eggs found in paleofeces and in the intestines of mummified humans . A. lumbricoides was originally called Lumbricus teres and was first described in detail by Edward Tyson in 1683. The genus Ascaris was originally described as the genus for Ascaris lumbricoides by Carl Linnaeus in 1758. The morphologically similar Ascaris suum
7708-643: The regions of Apulia and Calabria in Italy. In the framework of the European Charter for Regional or Minority Languages , Greek is protected and promoted officially as a regional and minority language in Armenia, Hungary , Romania, and Ukraine. It is recognized as a minority language and protected in Turkey by the 1923 Treaty of Lausanne . The phonology , morphology , syntax , and vocabulary of
7802-437: The stressed vowel; the so-called breathing marks ( rough and smooth breathing ), originally used to signal presence or absence of word-initial /h/; and the diaeresis , used to mark the full syllabic value of a vowel that would otherwise be read as part of a diphthong. These marks were introduced during the course of the Hellenistic period. Actual usage of the grave in handwriting saw a rapid decline in favor of uniform usage of
7896-830: The surface of the Earth in gold mines in South Africa. They represent 90% of all animals on the ocean floor . In total, 4.4 × 10 nematodes inhabit the Earth's topsoil, or approximately 60 billion for each human, with the highest densities observed in tundra and boreal forests. Their numerical dominance, often exceeding a million individuals per square meter and accounting for about 80% of all individual animals on Earth, their diversity of lifecycles, and their presence at various trophic levels point to an important role in many ecosystems. They have been shown to play crucial roles in polar ecosystems. The roughly 2,271 genera are placed in 256 families . The many parasitic forms include pathogens in most plants and animals. A third of
7990-414: The trichina worm, occurs in rats, pigs, bears, and humans, and is responsible for the disease trichinosis . Baylisascaris usually infests wild animals, but can be deadly to humans, as well. Dirofilaria immitis is known for causing heartworm disease by inhabiting the hearts, arteries, and lungs of dogs and some cats. Haemonchus contortus is one of the most abundant infectious agents in sheep around
8084-452: The wasp, and their offspring await the birth of the next generation of wasps as the fig ripens. A parasitic tetradonematid nematode discovered in 2005, Myrmeconema neotropicum , induces fruit mimicry in the tropical ant Cephalotes atratus . Infected ants develop bright red gasters (abdomens), tend to be more sluggish, and walk with their gasters in a conspicuous elevated position. These changes likely cause frugivorous birds to confuse
8178-432: The world, causing great economic damage to sheep. In contrast, entomopathogenic nematodes parasitize insects and are mostly considered beneficial by humans, but some attack beneficial insects. One form of nematode is entirely dependent upon fig wasps , which are the sole source of fig fertilization. They prey upon the wasps, riding them from the ripe fig of the wasp's birth to the fig flower of its death, where they kill
8272-574: Was a distinct dialect of Greek itself. Aside from the Macedonian question, current consensus regards Phrygian as the closest relative of Greek, since they share a number of phonological, morphological and lexical isoglosses , with some being exclusive between them. Scholars have proposed a Graeco-Phrygian subgroup out of which Greek and Phrygian originated. Among living languages, some Indo-Europeanists suggest that Greek may be most closely related to Armenian (see Graeco-Armenian ) or
8366-557: Was also used in Ancient Greek. Greek has occasionally been written in the Latin script , especially in areas under Venetian rule or by Greek Catholics . The term Frankolevantinika / Φραγκολεβαντίνικα applies when the Latin script is used to write Greek in the cultural ambit of Catholicism (because Frankos / Φράγκος is an older Greek term for West-European dating to when most of (Roman Catholic Christian) West Europe
8460-556: Was by far the most widely spoken lingua franca in the Mediterranean world . It eventually became the official language of the Byzantine Empire and developed into Medieval Greek . In its modern form , Greek is the official language of Greece and Cyprus and one of the 24 official languages of the European Union . It is spoken by at least 13.5 million people today in Greece, Cyprus, Italy, Albania, Turkey , and
8554-485: Was recorded in writing systems such as Linear B and the Cypriot syllabary . The alphabet arose from the Phoenician script and was in turn the basis of the Latin , Cyrillic , Coptic , Gothic , and many other writing systems. The Greek language holds a very important place in the history of the Western world. Beginning with the epics of Homer , ancient Greek literature includes many works of lasting importance in
8648-580: Was under the control of the Frankish Empire ). Frankochiotika / Φραγκοχιώτικα (meaning 'Catholic Chiot') alludes to the significant presence of Catholic missionaries based on the island of Chios . Additionally, the term Greeklish is often used when the Greek language is written in a Latin script in online communications. The Latin script is nowadays used by the Greek-speaking communities of Southern Italy . The Yevanic dialect
8742-637: Was used for literary and official purposes in the newly formed Greek state. In 1976, Dimotiki was declared the official language of Greece, after having incorporated features of Katharevousa and thus giving birth to Standard Modern Greek , used today for all official purposes and in education . The historical unity and continuing identity between the various stages of the Greek language are often emphasized. Although Greek has undergone morphological and phonological changes comparable to those seen in other languages, never since classical antiquity has its cultural, literary, and orthographic tradition been interrupted to
8836-673: Was written by Romaniote and Constantinopolitan Karaite Jews using the Hebrew Alphabet . In a tradition, that in modern time, has come to be known as Greek Aljamiado , some Greek Muslims from Crete wrote their Cretan Greek in the Arabic alphabet . The same happened among Epirote Muslims in Ioannina . This also happened among Arabic-speaking Byzantine rite Christians in the Levant ( Lebanon , Palestine, and Syria ). This usage
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