115-532: Hemicorallium is a genus of corals belonging to the family Coralliidae . The species of this genus are found in Pacific and Atlantic Ocean. Species: This Octocorallia -related article is a stub . You can help Misplaced Pages by expanding it . Corals Corals are colonial marine invertebrates within the subphylum Anthozoa of the phylum Cnidaria . They typically form compact colonies of many identical individual polyps . Coral species include
230-453: A symbiotic relationship with a class of dinoflagellate algae , zooxanthellae of the genus Symbiodinium , which can form as much as 30% of the tissue of a polyp. Typically, each polyp harbors one species of alga, and coral species show a preference for Symbiodinium . Young corals are not born with zooxanthellae, but acquire the algae from the surrounding environment, including the water column and local sediment. The main benefit of
345-420: A calcified material. The polyps of stony corals have six-fold symmetry. In stony corals, the tentacles are cylindrical and taper to a point, but in soft corals they are pinnate with side branches known as pinnules. In some tropical species, these are reduced to mere stubs and in some, they are fused to give a paddle-like appearance. Coral skeletons are biocomposites (mineral + organics) of calcium carbonate, in
460-491: A calcium carbonate base, with polyps that bear six stiff tentacles, and soft coral (Alcyonacea and ahermatypic coral) which are pliable and formed by a colony of polyps with eight feather-like tentacles. These two classifications arose from differentiation in gene expressions in their branch tips and bases that arose through developmental signaling pathways such as Hox , Hedgehog , Wnt , BMP etc. Scientists typically select Acropora as research models since they are
575-417: A commonly highly abundant bacterium in corals, has exhibited codiversification with its host. This hints at an intricate set of relationships between the members of the coral holobiont that have been developing as evolution of these members occurs. A study published in 2018 revealed evidence of phylosymbiosis between corals and their tissue and skeleton microbiomes. The coral skeleton, which represents
690-511: A compilation by Zechariah Aghmati called Sefer ha-Ner . The Tosafot are collected commentaries by various medieval Ashkenazic rabbis on the Talmud (known as Tosafists or Ba'alei Tosafot ). One of the main goals of the Tosafot is to explain and interpret contradictory statements in the Talmud. Unlike Rashi, the Tosafot is not a running commentary, but rather comments on selected matters. Often
805-567: A consensus view. The rabbis recorded in the Mishnah are known as the Tannaim (literally, "repeaters", or "teachers"). These tannaim—rabbis of the second century CE--"who produced the Mishnah and other tannaic works, must be distinguished from the rabbis of the third to fifth centuries, known as amoraim (literally, "speakers"), who produced the two Talmudim and other amoraic works". Since it sequences its laws by subject matter instead of by biblical context,
920-520: A full moon. A full moon is equivalent to four to six hours of continuous dim light exposure, which can cause light-dependent reactions in protein. Corals contain light-sensitive cryptochromes , proteins whose light-absorbing flavin structures are sensitive to different types of light. This allows corals such as Dipsastraea speciosa to detect and respond to changes in sunlight and moonlight. Moonlight itself may actually suppress coral spawning. The most immediate cue to cause spawning appears to be
1035-409: A list of types of trees, and the 11th-century French commentator Rashi describes it as "a type of tree (מין עץ) that grows underwater that goes by the (French) name 'coral'." The Persian polymath Al-Biruni (d.1048) classified sponges and corals as animals, arguing that they respond to touch. Nevertheless, people believed corals to be plants until the eighteenth century when William Herschel used
1150-582: A lower boundary on the dating of the Babylonian Talmud, it must post-date the early 5th century given its reliance on the Jerusalem Talmud . From the time of its completion, the Talmud became integral to Jewish scholarship. A maxim in Pirkei Avot advocates its study from the age of 15. This section outlines some of the major areas of Talmudic study. One area of Talmudic scholarship developed out of
1265-574: A microscope to establish that coral had the characteristic thin cell membranes of an animal . Presently, corals are classified as species of animals within the sub-classes Hexacorallia and Octocorallia of the class Anthozoa in the phylum Cnidaria . Hexacorallia includes the stony corals and these groups have polyps that generally have a 6-fold symmetry. Octocorallia includes blue coral and soft corals and species of Octocorallia have polyps with an eightfold symmetry, each polyp having eight tentacles and eight mesenteries . The group of corals
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#17330853156701380-441: A multi-domain marine animal symbiosis. The gammaproteobacterium Endozoicomonas is emerging as a central member of the coral's microbiome, with flexibility in its lifestyle. Given the recent mass bleaching occurring on reefs, corals will likely continue to be a useful and popular system for symbiosis and dysbiosis research. Astrangia poculata , the northern star coral, is a temperate stony coral , widely documented along
1495-514: A new colony. Although some corals are able to catch plankton and small fish using stinging cells on their tentacles, most corals obtain the majority of their energy and nutrients from photosynthetic unicellular dinoflagellates of the genus Symbiodinium that live within their tissues. These are commonly known as zooxanthellae and give the coral color. Such corals require sunlight and grow in clear, shallow water, typically at depths less than 60 metres (200 feet; 33 fathoms), but corals in
1610-492: A self-contained, edited passage known as a sugya . Much of the Gemara is legal in nature. Each analysis begins with a Mishnaic legal statement. With each sugya, the statement may be analyzed and compared with other statements. This process can be framed as an exchange between two (often anonymous, possibly metaphorical) disputants, termed the makshan (questioner) and tartzan (answerer). Gemara also commonly tries to find
1725-400: A single polyp and eventually develops into a juvenile and then adult by asexual budding and growth. Within a coral head, the genetically identical polyps reproduce asexually , either by budding (gemmation) or by dividing, whether longitudinally or transversely. Budding involves splitting a smaller polyp from an adult. As the new polyp grows, it forms its body parts . The distance between
1840-415: A skeleton composed of calcium carbonate to strengthen and protect the organism. This is deposited by the polyps and by the coenosarc , the living tissue that connects them. The polyps sit in cup-shaped depressions in the skeleton known as corallites . Colonies of stony coral are markedly variable in appearance; a single species may adopt an encrusting, plate-like, bushy, columnar or massive solid structure,
1955-640: A sole for one's foot. Despite its incomplete state, the Jerusalem Talmud remains an indispensable source of knowledge of the development of the Jewish Law in the Holy Land. It was also an important primary source for the study of the Babylonian Talmud by the Kairouan school of Chananel ben Chushiel and Nissim ben Jacob , with the result that opinions ultimately based on the Jerusalem Talmud found their way into both
2070-453: A subset of coral-associated bacteria. Many corals in the order Scleractinia are hermatypic , meaning that they are involved in building reefs. Most such corals obtain some of their energy from zooxanthellae in the genus Symbiodinium . These are symbiotic photosynthetic dinoflagellates which require sunlight; reef-forming corals are therefore found mainly in shallow water. They secrete calcium carbonate to form hard skeletons that become
2185-643: A third nature ( tertia natura )". Petrus Gyllius copied Pliny, introducing the term zoophyta for this third group in his 1535 book On the French and Latin Names of the Fishes of the Marseilles Region ; it is popularly but wrongly supposed that Aristotle created the term. Gyllius further noted, following Aristotle, how hard it was to define what was a plant and what was an animal. The Babylonian Talmud refers to coral among
2300-531: Is paraphyletic because the sea anemones are also in the sub-class Hexacorallia. The delineation of coral species is challenging as hypotheses based on morphological traits contradict hypotheses formed via molecular tree-based processes. As of 2020, there are 2175 identified separate coral species, 237 of which are currently endangered, making distinguishing corals to be the utmost of importance in efforts to curb extinction. Adaptation and delineation continues to occur in species of coral in order to combat
2415-409: Is coordinated by chemical communication. Corals predominantly reproduce sexually . About 25% of hermatypic corals (reef-building stony corals) form single-sex ( gonochoristic ) colonies, while the rest are hermaphroditic . It is estimated more than 67% of coral are simultaneous hermaphrodites . About 75% of all hermatypic corals "broadcast spawn" by releasing gametes — eggs and sperm —into
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#17330853156702530-558: Is during this period that rabbinic discourse began to be recorded in writing. In antiquity, the two major centres of Jewish scholarship were located in Galilee and Babylonia . A Talmud was compiled in each of these regional centres. The earlier of the two compilations took place in Galilee, either in the late fourth or early fifth century, and it came to be known as the Jerusalem Talmud (or Talmud Yerushalmi ). Later on, and likely some time in
2645-811: Is largely in Jewish Babylonian Aramaic , although quotations in the Gemara of the Mishnah, the Baraitas and Tanakh appear in Mishnaic or Biblical Hebrew. Some other dialects of Aramaic occur in quotations of other older works, like the Megillat Taanit . The reason why earlier texts occur in Hebrew, and later texts in Aramaic, is because of the adoption of the latter (which was the spoken vernacular) by rabbinic circles during
2760-415: Is negatively buoyant, sinking onto the waiting egg carriers that harbor unfertilized eggs for weeks. Synchronous spawning events sometimes occur even with these species. After fertilization, the corals release planula that are ready to settle. The time from spawning to larval settlement is usually two to three days but can occur immediately or up to two months. Broadcast-spawned planula larvae develop at
2875-456: Is often criticized as being a modern-day version of pilpul . Nevertheless, the influence of the Brisker method is great. Most modern-day Yeshivot study the Talmud using the Brisker method in some form. One feature of this method is the use of Maimonides ' Mishneh Torah as a guide to Talmudic interpretation, as distinct from its use as a source of practical halakha . Rival methods were those of
2990-609: Is primarily because the prestige of the Jewish community of Israel steadily declined in contrast with the Babylonian community in the years after the redaction of the Talmud and continuing until the Gaonic era. Maimonides claims that all Jewish communities in the Gaonic period formally accepted the Babylonian Talmud as binding, and that in any areas where the two Talmuds conflict, deference is given to
3105-443: Is regarded as more comprehensive. The structure of the Talmud follows that of the Mishnah, in which six orders ( sedarim ; singular: seder ) of general subject matter are divided into 60 or 63 tractates ( masekhtot ; singular: masekhet ) of more focused subject compilations, though not all tractates have Gemara. Each tractate is divided into chapters ( perakim ; singular: perek ), 517 in total, that are both numbered according to
3220-449: Is thought to have been laid down about two million years ago. Over time, corals fragment and die, sand and rubble accumulates between the corals, and the shells of clams and other molluscs decay to form a gradually evolving calcium carbonate structure. Coral reefs are extremely diverse marine ecosystems hosting over 4,000 species of fish, massive numbers of cnidarians, molluscs , crustaceans , and many other animals. At certain times in
3335-553: Is written largely in Jewish Palestinian Aramaic , a Western Aramaic language that differs from its Babylonian counterpart . The eye and the heart are two abettors to the crime. The final redaction of the text was in the late fourth or early fifth century, once Christianity had become the state religion of the Roman Empire and Jerusalem. Just as wisdom has made a crown for one's head, so, too, humility has made
3450-669: The Talmuda de-Eretz Yisrael ("Talmud of the Land of Israel"). Prior to being written down, it was transmitted orally for centuries and represents a compilation of scholastic teachings and analyses on the Mishnah (especially those concerning agricultural laws) found across regional centres of the Land of Israel now known as the Academies in Galilee (principally those of Tiberias , Sepphoris , and Caesarea ). It
3565-453: The Aggadic material from the Talmud. It was intended to familiarize the public with the ethical parts of the Talmud and to dispute many of the accusations surrounding its contents. Geonic -era (6th-11th centuries) commentaries have largely been lost, but are known to exist from partial quotations in later medieval and early modern texts. Because of this, it is known that now-lost commentaries on
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3680-593: The Cambrian about 535 million years ago . Fossils are extremely rare until the Ordovician period, 100 million years later, when Heliolitida, rugose , and tabulate corals became widespread. Paleozoic corals often contained numerous endobiotic symbionts. Babylonian Talmud The Talmud ( / ˈ t ɑː l m ʊ d , - m ə d , ˈ t æ l -/ ; Hebrew : תַּלְמוּד , romanized : Talmūḏ , lit. 'teaching') is, after
3795-555: The Gemara ( גמרא , c. 500 CE), a commentary of the Mishnah and related Tannaitic writings whose greater goal is to systematically understand the Hebrew Bible . Sometimes, the term "Talmud" is only used for the Gemara. As a whole, the traditions of the Talmud emerged in a literary tradition that occurred between the destruction of the Second Temple in 70 CE and the Arab conquest in
3910-401: The Hebrew Bible , the central text of Rabbinic Judaism and the primary source of Jewish religious law ( halakha ) and Jewish theology . Until the advent of modernity , in nearly all Jewish communities, the Talmud was the centerpiece of Jewish cultural life and was foundational to "all Jewish thought and aspirations", serving also as "the guide for the daily life" of Jews. Above all,
4025-494: The Hebrew alphabet and given names, usually using the first one or two words in the first Mishnah. A perek may continue over several (up to tens of) pages . Each perek will contain several mishnayot . The Mishnah is a compilation of legal opinions and debates. Statements in the Mishnah are typically terse, recording brief opinions of the rabbis debating a subject; or recording only an unattributed ruling, apparently representing
4140-503: The Mir and Telz yeshivas . See Chaim Rabinowitz § Telshe and Yeshiva Ohel Torah-Baranovich § Style of learning . The text of the Talmud has been subject to some level of critical scrutiny throughout its history. Rabbinic tradition holds that the people cited in both Talmuds did not have a hand in its writings; rather, their teachings were edited into a rough form around 450 CE (Talmud Yerushalmi) and 550 CE (Talmud Bavli.) The text of
4255-598: The Mishnah and the Babylonian Gemara, the latter representing the culmination of more than 300 years of analysis of the Mishnah in the Talmudic Academies in Babylonia. The foundations of this process of analysis were laid by Abba Arika (175–247), a disciple of Judah ha-Nasi . Tradition ascribes the compilation of the Babylonian Talmud in its present form to two Babylonian sages, Rav Ashi and Ravina II . Rav Ashi
4370-458: The Tosafot and the Mishneh Torah of Maimonides . Ethical maxims contained in the Jerusalem Talmud are scattered and interspersed in the legal discussions throughout the several treatises, many of which differ from those in the Babylonian Talmud. The Babylonian Talmud ( Talmud Bavli ) consists of documents compiled over the period of late antiquity (3rd to 6th centuries). During this time,
4485-502: The red coral , korallion , in his book on stones, implying it was a mineral, but he described it as a deep-sea plant in his Enquiries on Plants , where he also mentions large stony plants that reveal bright flowers when under water in the Gulf of Heroes . Pliny the Elder stated boldly that several sea creatures including sea nettles and sponges "are neither animals nor plants, but are possessed of
4600-467: The 15th and 16th centuries, a new intensive form of Talmud study arose. Complicated logical arguments were used to explain minor points of contradiction within the Talmud. The term pilpul was applied to this type of study. Usage of pilpul in this sense (that of "sharp analysis") harks back to the Talmudic era and refers to the intellectual sharpness this method demanded. Pilpul practitioners posited that
4715-498: The 15th century on, some authorities sought to apply the methods of Aristotelian logic , as reformulated by Averroes . This method was first recorded, though without explicit reference to Aristotle, by Isaac Campanton (d. Spain, 1463) in his Darkhei ha-Talmud ("The Ways of the Talmud"), and is also found in the works of Moses Chaim Luzzatto . According to the present-day Sephardi scholar José Faur , traditional Sephardic Talmud study could take place on any of three levels. In
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4830-467: The 18th century, pilpul study waned. Other styles of learning such as that of the school of Elijah b. Solomon, the Vilna Gaon , became popular. The term "pilpul" was increasingly applied derogatorily to novellae deemed casuistic and hairsplitting. Authors referred to their own commentaries as "al derekh ha-peshat" (by the simple method) to contrast them with pilpul. Among Sephardi and Italian Jews from
4945-456: The 5th century by Rav Ashi and Ravina II . There is also an earlier collection known as the Jerusalem Talmud ( Talmud Yerushalmi ). It may also traditionally be called Shas ( ש״ס ), a Hebrew abbreviation of shisha sedarim , or the "six orders" of the Mishnah . The Talmud has two components: the Mishnah ( משנה , c. 200 CE), a written compendium of the Oral Torah ; and
5060-450: The Acropora genus, colony differentiation through up-regulation and down-regulation of DEs. Systematic studies of soft coral species have faced challenges due to a lack of taxonomic knowledge. Researchers have not found enough variability within the genus to confidently delineate similar species, due to a low rate in mutation of mitochondrial DNA . Environmental factors, such as
5175-581: The Babylonian Talmud may draw upon the Mishnah, the Jerusalem Talmud, midrash, and other sources. The traditions that the Gemara comments on are not limited to what is found in the Mishnah, but the Baraita as well (a term that broadly designates Oral Torah traditions that did not end up in the Mishnah). The baraitot cited in the Gemara are often quotations from the Tosefta (a tannaitic compendium of halakha parallel to
5290-585: The Babylonian opinion. Neither covers the entire Mishnah. For example, the Babylonian commentary only covers 37 of 63 Mishnaic tractates. In particular: The Babylonian Talmud records the opinions of the rabbis of the Ma'arava (the West, meaning Israel) as well as of those of Babylonia, while the Jerusalem Talmud seldom cites the Babylonian rabbis. The Babylonian version also contains the opinions of more generations because of its later date of completion. For both these reasons, it
5405-531: The Illumina platform are of insufficient length (approximately 250 base pairs) for the design of primers and probes. In 2019, Goldsmith et al. demonstrated Sanger sequencing was capable of reproducing the biologically relevant diversity detected by deeper next-generation sequencing , while also producing longer sequences useful to the research community for probe and primer design (see diagram on right). Reef-building corals are well-studied holobionts that include
5520-596: The International Union for Conservation of Nature's endangered species list and at risk of species loss. Ocean acidification (falling pH levels in the oceans) is threatening the continued species growth and differentiation of corals. Mutation rates of Vibrio shilonii , the reef pathogen responsible for coral bleaching , heavily outweigh the typical reproduction rates of coral colonies when pH levels fall. Thus, corals are unable to mutate their HSPs and other climate change preventative genes to combat
5635-531: The Mishnah discusses individual subjects more thoroughly than the Midrash , and it includes a much broader selection of halakhic subjects than the Midrash. The Mishnah's topical organization thus became the framework of the Talmud as a whole. But not every tractate in the Mishnah has a corresponding Gemara. Also, the order of the tractates in the Talmud differs in some cases from that in the Mishnah . The Gemara constitutes
5750-409: The Mishnah) and the Midrash halakha (specifically Mekhilta, Sifra and Sifre ). Some baraitot , however, are known only through traditions cited in the Gemara, and are not part of any other collection. In addition to the six Orders, the Talmud contains a series of short treatises of a later date, usually printed at the end of Seder Nezikin. These are not divided into Mishnah and Gemara. The work
5865-504: The Roman destruction of the Jewish commonwealth and the Second Temple in the year 70 and the consequent upheaval of Jewish social and legal norms. As the rabbis were required to face a new reality—mainly Judaism without a Temple (to serve as the center of teaching and study) and total Roman control over Judaea , without at least partial autonomy—there was a flurry of legal discourse and the old system of oral scholarship could not be maintained. It
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#17330853156705980-746: The Talmud after the end of the Amoraic period, known as the Savoraim or Rabbanan Savora'e (meaning "reasoners" or "considerers"). Unlike the Western Aramaic dialect of the Jerusalm Talmud, the Babylonian Talmud has a Babylonian Aramaic dialect. The Jerusalem is also more fragmentary (and difficult to read) due to a less complete redactional process . Legally, the two differ minimally. The Babylonian Talmud has received significantly more interest and coverage from commentators. This significantly greater influence
6095-502: The Talmud could contain no redundancy or contradiction whatsoever. New categories and distinctions ( hillukim ) were therefore created, resolving seeming contradictions within the Talmud by novel logical means. In the Ashkenazi world the founders of pilpul are generally considered to be Jacob Pollak (1460–1541) and Shalom Shachna . This kind of study reached its height in the 16th and 17th centuries when expertise in pilpulistic analysis
6210-498: The Talmud is a commentary on the Mishnah , primarily written in Jewish Babylonian Aramaic . It contains the teachings and opinions of thousands of rabbis on a variety of subjects, including halakha , Jewish ethics , philosophy , customs , history , and folklore , and many other topics. The term Talmud normally refers to the collection of writings named specifically the Babylonian Talmud ( Talmud Bavli ), compiled in
6325-597: The Talmud was compiled appears to have been forgotten at least by the second half of the Middle Ages, when estimates between the 3rd century BCE to the 9th century CE are suggested in the Wikkuah , a text that records the debates that took place in the Disputation of Paris (also known as the "Trial of the Talmud") which took place in 1240. A wide range of dates have been proposed for the Babylonian Talmud by historians. The text
6440-402: The Talmud were written by Paltoi Gaon, Sherira , Hai Gaon , and Saadya (though in this case, Saadiya is not likely to be the true author). Of these, the commentary of Paltoi ben Abaye ( c. 840) is the earliest. His son, Zemah ben Paltoi paraphrased and explained the passages which he quoted; and he composed, as an aid to the study of the Talmud, a lexicon which Abraham Zacuto consulted in
6555-460: The Talmud, has become a classic. Sections in the commentary covering a few tractates (Pes, BB and Mak) were completed by his students, especially Judah ben Nathan , and a sections dealing with specific tractates (Ned, Naz, Hor and MQ) of the commentary that appear in some print editions of Rashi's commentary today were not composed by him. In the twelfth and thirteenth centuries, a genre of rabbinic literature emerged surrounding Rashi's commentary, with
6670-405: The abundance and performance of the microalgal symbionts, as well as calcification and physiology of the host. Studies have also suggested that resident bacteria, archaea, and fungi additionally contribute to nutrient and organic matter cycling within the coral, with viruses also possibly playing a role in structuring the composition of these members, thus providing one of the first glimpses at
6785-407: The algae contribute to coral coloration; some colors, however, are due to host coral pigments, such as green fluorescent proteins (GFPs). Ejection increases the polyp's chance of surviving short-term stress and if the stress subsides they can regain algae, possibly of a different species, at a later time. If the stressful conditions persist, the polyp eventually dies. Zooxanthellae are located within
6900-487: The area has decreased and in some cases ceased. The area was previously considered a refuge for corals because mass bleaching events due to climate change had not been observed there. Coral restoration techniques for coral reef management are being developed to increase fertilization rates, larval development, and settlement of new corals. Brooding species are most often ahermatypic (not reef-building) in areas of high current or wave action. Brooders release only sperm, which
7015-458: The capture of food. Polyps extend their tentacles, particularly at night, often containing coiled stinging cells ( cnidocytes ) which pierce, poison and firmly hold living prey paralyzing or killing them. Polyp prey includes plankton such as copepods and fish larvae. Longitudinal muscular fibers formed from the cells of the ectoderm allow tentacles to contract to convey the food to the mouth. Similarly, circularly disposed muscular fibres formed from
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#17330853156707130-507: The cell layers of the body wall. The mesoglea can contain skeletal elements derived from cells migrated from the ectoderm. The sac-like body built up in this way is attached to a hard surface, which in hard corals are cup-shaped depressions in the skeleton known as corallites . At the center of the upper end of the sac lies the only opening called the mouth, surrounded by a circle of tentacles which resemble glove fingers. The tentacles are organs which serve both for tactile sense and for
7245-558: The cold-water genus Lophelia which can survive as deep as 3,300 metres (10,800 feet; 1,800 fathoms). Some have been found as far north as the Darwin Mounds , northwest of Cape Wrath , Scotland, and others off the coast of Washington state and the Aleutian Islands . The classification of corals has been discussed for millennia, owing to having similarities to both plants and animals. Aristotle 's pupil Theophrastus described
7360-440: The colony during storms or other disruptions. The separated individuals can start new colonies. Corals are one of the more common examples of an animal host whose symbiosis with microalgae can turn to dysbiosis , and is visibly detected as bleaching. Coral microbiomes have been examined in a variety of studies, which demonstrate how oceanic environmental variations, most notably temperature, light, and inorganic nutrients, affect
7475-421: The colony thus creates a skeleton characteristic of the species which can measure up to several meters in size. Individual colonies grow by asexual reproduction of polyps. Corals also breed sexually by spawning : polyps of the same species release gametes simultaneously overnight, often around a full moon . Fertilized eggs form planulae, a mobile early form of the coral polyp which, when mature, settles to form
7590-504: The commentary portion of the Talmud. The Mishnah, and its commentary (the Gemara), together constitute the Talmud. This commentary arises from a longstanding tradition of rabbis analyzing, debating, and discussing the Mishnah ever since it had been published. The rabbis who participated in the process that produced this commentarial tradition are known as the Amoraim . Each discussion is presented in
7705-797: The coral cytoplasm and due to the algae's photosynthetic activity the internal pH of the coral can be raised; this behavior indicates that the zooxanthellae are responsible to some extent for the metabolism of their host corals. Stony Coral Tissue Loss Disease has been associated with the breakdown of host-zooxanthellae physiology. Moreover, Vibrio bacterium are known to have virulence traits used for host coral tissue damage and photoinhibition of algal symbionts. Therefore, both coral and their symbiotic microorganisms could have evolved to harbour traits resistant to disease and transmission. Corals can be both gonochoristic (unisexual) and hermaphroditic , each of which can reproduce sexually and asexually. Reproduction also allows coral to settle in new areas. Reproduction
7820-591: The coral itself together with its symbiont zooxanthellae (photosynthetic dinoflagellates), as well as its associated bacteria and viruses. Co-evolutionary patterns exist for coral microbial communities and coral phylogeny. It is known that the coral's microbiome and symbiont influence host health, however, the historic influence of each member on others is not well understood. Scleractinian corals have been diversifying for longer than many other symbiotic systems, and their microbiomes are known to be partially species-specific. It has been suggested that Endozoicomonas ,
7935-598: The corals supplementing their plankton diet with the products of photosynthesis produced by these symbionts . The polyps interconnect by a complex and well-developed system of gastrovascular canals, allowing significant sharing of nutrients and symbionts. The external form of the polyp varies greatly. The column may be long and slender, or may be so short in the axial direction that the body becomes disk-like. The tentacles may number many hundreds or may be very few, in rare cases only one or two. They may be simple and unbranched, or feathery in pattern. The mouth may be level with
8050-409: The correct biblical basis for a given law in the Mishnah as well as the logical process that connects the biblical to the Mishnaic tradition. This process was known as talmud , long before the "Talmud" itself became a text. In addition, the Gemara contains a wide range of narratives, homiletical or exegetical passages, sayings, and other non-legal content, termed aggadah . A story told in a sugya of
8165-578: The dangers posed by the climate crisis. Corals are colonial modular organisms formed by asexually produced and genetically identical modules called polyps. Polyps are connected by living tissue to produce the full organism. The living tissue allows for inter module communication (interaction between each polyp), which appears in colony morphologies produced by corals, and is one of the main identifying characteristics for a species of coral. There are two main classifications for corals: hard coral (scleractinian and stony coral) which form reefs by
8280-434: The dark portion of the night between sunset and moonrise. Over the lunar cycle, moonrise shifts progressively later, occurring after sunset on the day of the full moon. The resulting dark period between day-light and night-light removes the suppressive effect of moonlight and enables coral to spawn. The spawning event can be visually dramatic, clouding the usually clear water with gametes. Once released, gametes fertilize at
8395-509: The early seventh century. In all, the Talmud is divided into 63 tractates , with each tractate systematically discussing one general subject or theme. In the standard print of the Talmud (the Vilna Shas ), the Talmud runs to a length of 2,711 double-sided folios . Talmud translates as "instruction, learning", from the Semitic root lmd , meaning "teach, study". Originally, Jewish scholarship
8510-476: The eastern coast of the United States. The coral can live with and without zooxanthellae (algal symbionts), making it an ideal model organism to study microbial community interactions associated with symbiotic state. However, the ability to develop primers and probes to more specifically target key microbial groups has been hindered by the lack of full-length 16S rRNA sequences, since sequences produced by
8625-525: The endoderm permit tentacles to be protracted or thrust out once they are contracted. In both stony and soft corals, the polyps can be retracted by contracting muscle fibres, with stony corals relying on their hard skeleton and cnidocytes for defense. Soft corals generally secrete terpenoid toxins to ward off predators. In most corals, the tentacles are retracted by day and spread out at night to catch plankton and other small organisms. Shallow-water species of both stony and soft corals can be zooxanthellate ,
8740-426: The exoskeleton divide transversally into two parts. This means one has the basal disc (bottom) and the other has the oral disc (top); the new polyps must separately generate the missing pieces. Asexual reproduction offers the benefits of high reproductive rate, delaying senescence, and replacement of dead modules, as well as geographical distribution. Whole colonies can reproduce asexually, forming two colonies with
8855-461: The explanations of Tosafot differ from those of Rashi. Among the founders of the Tosafist school were Rabbeinu Tam , who was a grandson of Rashi, and, Rabbenu Tam's nephew, Isaac ben Samuel . The Tosafot commentaries were collected in different editions in the various schools. The benchmark collection of Tosafot for Northern France was that of Eliezer of Touques . The standard collection for Spain
8970-426: The fifteenth century. Saadia Gaon is said to have composed commentaries on the Talmud, aside from his Arabic commentaries on the Mishnah. The first surviving commentary on the entire Talmud is that of Chananel ben Chushiel . Many medieval authors also composed commentaries focusing on the content of specific tractates, including Nissim ben Jacob and Gershom ben Judah . The commentary of Rashi , covering most of
9085-400: The form of calcite or aragonite. In scleractinian corals, "centers of calcification" and fibers are clearly distinct structures differing with respect to both morphology and chemical compositions of the crystalline units. The organic matrices extracted from diverse species are acidic, and comprise proteins, sulphated sugars and lipids; they are species specific. The soluble organic matrices of
9200-498: The framework of the reef. However, not all reef-building corals in shallow water contain zooxanthellae, and some deep water species, living at depths to which light cannot penetrate, form reefs but do not harbour the symbionts. There are various types of shallow-water coral reef, including fringing reefs, barrier reefs and atolls; most occur in tropical and subtropical seas. They are very slow-growing, adding perhaps one centimetre (0.4 in) in height each year. The Great Barrier Reef
9315-593: The genus Leptoseris have been found as deep as 172 metres (564 feet; 94 fathoms). Corals are major contributors to the physical structure of the coral reefs that develop in tropical and subtropical waters, such as the Great Barrier Reef off the coast of Australia . These corals are increasingly at risk of bleaching events where polyps expel the zooxanthellae in response to stress such as high water temperature or toxins. Other corals do not rely on zooxanthellae and can live globally in much deeper water, such as
9430-633: The geological past, corals were very abundant. Like modern corals, their ancestors built reefs, some of which ended as great structures in sedimentary rocks . Fossils of fellow reef-dwellers algae, sponges, and the remains of many echinoids , brachiopods , bivalves , gastropods , and trilobites appear along with coral fossils. This makes some corals useful index fossils . Coral fossils are not restricted to reef remnants, and many solitary fossils are found elsewhere, such as Cyclocyathus , which occurs in England's Gault clay formation. Corals first appeared in
9545-430: The important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton. A coral "group" is a colony of very many genetically identical polyps. Each polyp is a sac-like animal typically only a few millimeters in diameter and a few centimeters in height. A set of tentacles surround a central mouth opening. Each polyp excretes an exoskeleton near the base. Over many generations,
9660-436: The increase in temperature and decrease in pH at a competitive rate to these pathogens responsible for coral bleaching, resulting in species loss. For most of their life corals are sessile animals of colonies of genetically identical polyps . Each polyp varies from millimeters to centimeters in diameter, and colonies can be formed from many millions of individual polyps. Stony coral, also known as hard coral, polyps produce
9775-455: The late 19th century another trend in Talmud study arose. Hayyim Soloveitchik (1853–1918) of Brisk (Brest-Litovsk) developed and refined this style of study. Brisker method involves a reductionistic analysis of rabbinic arguments within the Talmud or among the Rishonim , explaining the differing opinions by placing them within a categorical structure. The Brisker method is highly analytical and
9890-458: The most diverse genus of hard coral, having over 120 species. Most species within this genus have polyps which are dimorphic: axial polyps grow rapidly and have lighter coloration, while radial polyps are small and are darker in coloration. In the Acropora genus, gamete synthesis and photosynthesis occur at the basal polyps, growth occurs mainly at the radial polyps. Growth at the site of
10005-418: The most diverse of the three coral microbiomes, showed the strongest evidence of phylosymbiosis. Coral microbiome composition and richness were found to reflect coral phylogeny . For example, interactions between bacterial and eukaryotic coral phylogeny influence the abundance of Endozoicomonas , a highly abundant bacterium in the coral holobiont. However, host-microbial cophylogeny appears to influence only
10120-572: The most important of the Jewish centres in Mesopotamia , a region called " Babylonia " in Jewish sources (see Talmudic academies in Babylonia ) and later known as Iraq , were Nehardea , Nisibis (modern Nusaybin ), Mahoza ( al-Mada'in , just to the south of what is now Baghdad ), Pumbedita (near present-day al Anbar Governorate ), and the Sura Academy , probably located about 60 km (37 mi) south of Baghdad. The Babylonian Talmud comprises
10235-478: The need to ascertain the Halakha (Jewish rabbinical law). Early commentators such as Isaac Alfasi (North Africa, 1013–1103) attempted to extract and determine the binding legal opinions from the vast corpus of the Talmud. Alfasi's work was highly influential, attracted several commentaries in its own right and later served as a basis for the creation of halakhic codes. Another influential medieval Halakhic work following
10350-637: The new and adult polyps grows, and with it, the coenosarc (the common body of the colony). Budding can be intratentacular, from its oral discs, producing same-sized polyps within the ring of tentacles, or extratentacular, from its base, producing a smaller polyp. Division forms two polyps that each become as large as the original. Longitudinal division begins when a polyp broadens and then divides its coelenteron (body), effectively splitting along its length. The mouth divides and new tentacles form. The two polyps thus created then generate their missing body parts and exoskeleton. Transversal division occurs when polyps and
10465-592: The order of the Babylonian Talmud, and to some extent modelled on Alfasi, was "the Mordechai ", a compilation by Mordechai ben Hillel ( c. 1250–1298). A third such work was that of Asher ben Yechiel (d. 1327). All these works and their commentaries are printed in the Vilna and many subsequent editions of the Talmud. A 15th-century Spanish rabbi, Jacob ibn Habib (d. 1516), compiled the Ein Yaakov , which extracts nearly all
10580-587: The period of the Amoraim (rabbis cited in the Gemara) beginning around the year 200. A second Aramaic dialect is used in Nedarim , Nazir , Temurah , Keritot , and Me'ilah ; the second is closer in style to the Targum . The oldest full manuscript of the Talmud, known as the Munich Talmud (Codex Hebraicus 95), dates from 1342 and is available online. Manuscripts of the Talmud are as follows: The exact date at which
10695-416: The polyps of most are connected by sheets of tissue called coenosarc, and in some species these sheets are thick and the polyps deeply embedded in them. Some soft corals encrust other sea objects or form lobes. Others are tree-like or whip-like and have a central axial skeleton embedded at their base in the matrix of the supporting branch. These branches are composed of a fibrous protein called gorgonin or of
10810-691: The purpose of supplementing it and addressing internal contradictions via the technique of pilpul . This genre of commentary is known as the Tosafot and focuses on specific passages instead of a running continuous commentary across the entire Talmud. Many Talmudic passages are difficult to understand, sometimes owing to the use of Greek or Persian loanwords whose meaning had become obscure. A major area of Talmudic scholarship developed to explain these passages and words. Some early commentators such as Rabbenu Gershom of Mainz (10th century) and Rabbenu Ḥananel (early 11th century) produced running commentaries to various tractates. These commentaries could be read with
10925-412: The radial polyps encompasses two processes: asexual reproduction via mitotic cell proliferation , and skeleton deposition of the calcium carbonate via extra cellular matrix (EMC) proteins acting as differentially expressed (DE) signaling genes between both branch tips and bases. These processes lead to colony differentiation , which is the most accurate distinguisher between coral species. In
11040-440: The rise of temperatures and acid levels in our oceans account for some speciation of corals in the form of species lost . Various coral species have heat shock proteins (HSP) that are also in the category of DE across species. These HSPs help corals combat the increased temperatures they are facing which lead to protein denaturing, growth loss, and eventually coral death. Approximately 33% of coral species are on
11155-406: The same genotype. The possible mechanisms include fission, bailout and fragmentation. Fission occurs in some corals, especially among the family Fungiidae , where the colony splits into two or more colonies during early developmental stages. Bailout occurs when a single polyp abandons the colony and settles on a different substrate to create a new colony. Fragmentation involves individuals broken from
11270-563: The same night even when multiple species are present. Synchronous spawning may form hybrids and is perhaps involved in coral speciation . Environmental cues that influence the release of gametes into the water vary from species to species. The cues involve temperature change, lunar cycle , day length , and possibly chemical signalling. Other factors that affect the rhythmicity of organisms in marine habitats include salinity, mechanical forces, and pressure or magnetic field changes. Mass coral spawning often occurs at night on days following
11385-523: The sixth century, the Babylonian Talmud was compiled. This later Talmud is usually what is being referred to when the word "Talmud" is used without qualification. The two Talmuds were likely written independently of one another. The Jerusalem Talmud ( Talmud Yerushalmi ) is known by several other names, including the Palestinian Talmud (which is more accurate, as it was not compiled in Jerusalem ), or
11500-409: The skeleton, with the latter showing the greatest microbial richness. The zooxanthellae benefit from a safe place to live and consume the polyp's carbon dioxide , phosphate and nitrogenous waste. Stressed corals will eject their zooxanthellae, a process that is becoming increasingly common due to strain placed on coral by rising ocean temperatures. Mass ejections are known as coral bleaching because
11615-433: The skeletons allow to differentiate zooxanthellae and non-zooxanthellae specimens. Polyps feed on a variety of small organisms, from microscopic zooplankton to small fish. The polyp's tentacles immobilize or kill prey using stinging cells called nematocysts . These cells carry venom which they rapidly release in response to contact with another organism. A dormant nematocyst discharges in response to nearby prey touching
11730-548: The surface of the peristome, or may be projecting and trumpet-shaped. Soft corals have no solid exoskeleton as such. However, their tissues are often reinforced by small supportive elements known as sclerites made of calcium carbonate. The polyps of soft corals have eight-fold symmetry, which is reflected in the Octo in Octocorallia. Soft corals vary considerably in form, and most are colonial. A few soft corals are stolonate , but
11845-476: The text likely trace to this time regardless of the date of the final redaction/compilation. Additional external evidence for a latest possible date for the composition of the Babylonian Talmud are the uses of it by external sources, including the Letter of Baboi (mid-8th century), Seder Tannaim veAmoraim (9th century) and a 10th-century letter by Sherira Gaon addressing the formation of the Babylonian Talmud. As for
11960-611: The text of the Talmud and would help explain the meaning of the text. Another important work is the Sefer ha-Mafteaḥ (Book of the Key) by Nissim Gaon , which contains a preface explaining the different forms of Talmudic argumentation and then explains abbreviated passages in the Talmud by cross-referring to parallel passages where the same thought is expressed in full. Commentaries ( ḥiddushim ) by Joseph ibn Migash on two tractates, Bava Batra and Shevuot, based on Ḥananel and Alfasi, also survive, as does
12075-454: The trigger ( Cnidocil ). A flap ( operculum ) opens and its stinging apparatus fires the barb into the prey. The venom is injected through the hollow filament to immobilise the prey; the tentacles then manoeuvre the prey into the stomach. Once the prey is digested the stomach reopens allowing the elimination of waste products and the beginning of the next hunting cycle. Many corals, as well as other cnidarian groups such as sea anemones form
12190-466: The various forms often being linked to different types of habitat, with variations in light level and water movement being significant. The body of the polyp may be roughly compared in a structure to a sac , the wall of which is composed of two layers of cells . The outer layer is known technically as the ectoderm , the inner layer as the endoderm . Between ectoderm and endoderm is a supporting layer of gelatinous substance termed mesoglea , secreted by
12305-427: The water where they meet and fertilize to spread offspring. Corals often synchronize their time of spawning. This reproductive synchrony is essential so that male and female gametes can meet. Spawning frequently takes place in the evening or at night, and can occur as infrequently as once a year, and within a window of 10–30 minutes. Synchronous spawning is very typical on the coral reef, and often, all corals spawn on
12420-537: The water's surface and form a microscopic larva called a planula , typically pink and elliptical in shape. A typical coral colony needs to release several thousand larvae per year to overcome the odds against formation of a new colony. Studies suggest that light pollution desynchronizes spawning in some coral species. In areas such as the Red Sea , as many as 10 out of 50 species may be showing spawning asynchrony, compared to 30 years ago. The establishment of new corals in
12535-559: The water's surface before descending to seek a hard surface on the benthos to which they can attach and begin a new colony. The larvae often need a biological cue to induce settlement such as specific crustose coralline algae species or microbial biofilms. High failure rates afflict many stages of this process, and even though thousands of eggs are released by each colony, few new colonies form. During settlement, larvae are inhibited by physical barriers such as sediment, as well as chemical (allelopathic) barriers. The larvae metamorphose into
12650-410: The zooxanthellae is their ability to photosynthesize which supplies corals with the products of photosynthesis, including glucose, glycerol, also amino acids, which the corals can use for energy. Zooxanthellae also benefit corals by aiding in calcification , for the coral skeleton, and waste removal. In addition to the soft tissue, microbiomes are also found in the coral's mucus and (in stony corals)
12765-430: Was Rabbenu Asher 's Tosefot haRosh. The Tosafot that are printed in the standard Vilna edition of the Talmud are an edited version compiled from the various medieval collections, predominantly that of Touques. A recent project, Halacha Brura , founded by Abraham Isaac Kook , presents the Talmud and a summary of the halachic codes side by side, so as to enable the "collation" of Talmud with resultant Halacha. During
12880-601: Was oral and transferred from one generation to the next. Rabbis expounded and debated the Torah (the written Torah expressed in the Hebrew Bible) and discussed the Tanakh without the benefit of written works (other than the Biblical books themselves), though some may have made private notes ( megillot setarim ), for example, of court decisions. This situation changed drastically due to
12995-665: Was considered an art form and became a goal in and of itself within the yeshivot of Poland and Lithuania. But the popular new method of Talmud study was not without critics; already in the 15th century, the ethical tract Orhot Zaddikim ("Paths of the Righteous" in Hebrew) criticized pilpul for an overemphasis on intellectual acuity. Many 16th- and 17th-century rabbis were also critical of pilpul. Among them are Judah Loew ben Bezalel (the Maharal of Prague), Isaiah Horowitz , and Yair Bacharach . By
13110-435: Was most likely completed, however, in the 6th century, or prior to the early Muslim conquests in 643–636 CE at the latest, on the basis that the Talmud lacks loanwords or syntax deriving from Arabic . Recently, it has been extensively argued that Talmud is an expression and product of Sasanian culture, as well as other Greek - Roman , Middle Persian , and Syriac sources up to the same period of time. The contents of
13225-480: Was president of the Sura Academy from 375 to 427. The work begun by Rav Ashi was completed by Ravina, who is traditionally regarded as the final Amoraic expounder. Accordingly, traditionalists argue that Ravina's death in 475 is the latest possible date for the completion of the redaction of the Talmud. However, even on the most traditional view, a few passages are regarded as the work of a group of rabbis who edited
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