67-809: Red algae , or Rhodophyta ( / r oʊ ˈ d ɒ f ɪ t ə / , / ˌ r oʊ d ə ˈ f aɪ t ə / ; from Ancient Greek ῥόδον ( rhódon ) 'rose' and φυτόν ( phutón ) 'plant'), make up one of the oldest groups of eukaryotic algae . The Rhodophyta comprises one of the largest phyla of algae , containing over 7,000 recognized species within over 900 genera amidst ongoing taxonomic revisions. The majority of species (6,793) are Florideophyceae , and mostly consist of multicellular , marine algae, including many notable seaweeds . Red algae are abundant in marine habitats. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations in warmer areas. Except for two coastal cave dwelling species in
134-468: A and d . Red algae are red due to phycoerythrin . They contain the sulfated polysaccharide carrageenan in the amorphous sections of their cell walls, although red algae from the genus Porphyra contain porphyran . They also produce a specific type of tannin called phlorotannins , but in a lower amount than brown algae do. As enlisted in realDB , 27 complete transcriptomes and 10 complete genomes sequences of red algae are available. Listed below are
201-558: A nucleus , a vacuole , and floridean starch . Pyrenoids are absent. Most are extremophiles inhabiting acid hot springs . They originated in extreme environments with high temperatures and low pH, which allowed them to occupy ecological niches without any competition. While still found in extreme environments, they have also adapted to live along streams, in fissures in rock walls and in soil, but usually prefer relatively high temperatures. They have never been found in basic freshwater or seawater habitats. The main photosynthetic pigment
268-537: A pitch accent . In Modern Greek, all vowels and consonants are short. Many vowels and diphthongs once pronounced distinctly are pronounced as /i/ ( iotacism ). Some of the stops and glides in diphthongs have become fricatives , and the pitch accent has changed to a stress accent . Many of the changes took place in the Koine Greek period. The writing system of Modern Greek, however, does not reflect all pronunciation changes. The examples below represent Attic Greek in
335-417: A tetrasporophyte – this produces spore tetrads, which dissociate and germinate into gametophytes. The gametophyte is typically (but not always) identical to the tetrasporophyte. Carpospores may also germinate directly into thalloid gametophytes, or the carposporophytes may produce a tetraspore without going through a (free-living) tetrasporophyte phase. Tetrasporangia may be arranged in a row ( zonate ), in
402-405: A 150 ug/day requirement of iodine is obtained from a single gram of red algae. Red algae, like Gracilaria , Gelidium , Euchema , Porphyra , Acanthophora , and Palmaria are primarily known for their industrial use for phycocolloids (agar, algin, furcellaran and carrageenan) as thickening agent, textiles, food, anticoagulants, water-binding agents, etc. Dulse ( Palmaria palmata )
469-479: A carbon source have less negative δ C values than those that only use CO 2 . An additional difference of about 1.71‰ separates groups intertidal from those below the lowest tide line, which are never exposed to atmospheric carbon. The latter group uses the more C-negative CO 2 dissolved in sea water, whereas those with access to atmospheric carbon reflect the more positive signature of this reserve. Photosynthetic pigments of Rhodophyta are chlorophylls
536-544: A cross (cruciate), or in a tetrad. The carposporophyte may be enclosed within the gametophyte, which may cover it with branches to form a cystocarp . The two following case studies may be helpful to understand some of the life histories algae may display: In a simple case, such as Rhodochorton investiens : A rather different example is Porphyra gardneri : The δ C values of red algae reflect their lifestyles. The largest difference results from their photosynthetic metabolic pathway : algae that use HCO 3 as
603-433: A double membrane, lack grana and phycobilisomes on the stromal surface of the thylakoid membrane. The major photosynthetic products include floridoside (major product), D‐isofloridoside, digeneaside, mannitol, sorbitol, dulcitol etc. Floridean starch (similar to amylopectin in land plants), a long-term storage product, is deposited freely (scattered) in the cytoplasm. The concentration of photosynthetic products are altered by
670-507: A few species can reach lengths of 2 m. In the SCRP clade the class Compsopogonophyceae is multicellular, with forms varying from microscopic filaments to macroalgae. Stylonematophyceae have both unicellular and small simple filamentous species, while Rhodellophyceae and Porphyridiophyceae are exclusively unicellular. Most rhodophytes are marine with a worldwide distribution, and are often found at greater depths compared to other seaweeds. While this
737-472: A lack of contemporaneous evidence. Several theories exist about what Hellenic dialect groups may have existed between the divergence of early Greek-like speech from the common Proto-Indo-European language and the Classical period. They have the same general outline but differ in some of the detail. The only attested dialect from this period is Mycenaean Greek , but its relationship to the historical dialects and
SECTION 10
#1733093115059804-419: A lesser degree. Pamphylian Greek , spoken in a small area on the southwestern coast of Anatolia and little preserved in inscriptions, may be either a fifth major dialect group, or it is Mycenaean Greek overlaid by Doric, with a non-Greek native influence. Regarding the speech of the ancient Macedonians diverse theories have been put forward, but the epigraphic activity and the archaeological discoveries in
871-473: A parasitic lifestyle and may be found on closely or more distantly related red algal hosts. In the classification system of Adl et al. 2005, the red algae are classified in the Archaeplastida , along with the glaucophytes and the green algae plus land plants ( Viridiplantae or Chloroplastida). The authors use a hierarchical arrangement where the clade names do not signify rank; the class name Rhodophyceae
938-415: A pit connection is formed, tubular membranes appear. A granular protein called the plug core then forms around the membranes. The tubular membranes eventually disappear. While some orders of red algae simply have a plug core, others have an associated membrane at each side of the protein mass, called cap membranes. The pit plug continues to exist between the cells until one of the cells dies. When this happens,
1005-543: A prefix /e-/, called the augment . This was probably originally a separate word, meaning something like "then", added because tenses in PIE had primarily aspectual meaning. The augment is added to the indicative of the aorist, imperfect, and pluperfect, but not to any of the other forms of the aorist (no other forms of the imperfect and pluperfect exist). The two kinds of augment in Greek are syllabic and quantitative. The syllabic augment
1072-671: A separate historical stage, though its earliest form closely resembles Attic Greek , and its latest form approaches Medieval Greek , and Koine may be classified as Ancient Greek in a wider sense. There were several regional dialects of Ancient Greek; Attic Greek developed into Koine. Ancient Greek was a pluricentric language , divided into many dialects. The main dialect groups are Attic and Ionic , Aeolic , Arcadocypriot , and Doric , many of them with several subdivisions. Some dialects are found in standardized literary forms in literature , while others are attested only in inscriptions. There are also several historical forms. Homeric Greek
1139-609: A standard subject of study in educational institutions of the Western world since the Renaissance . This article primarily contains information about the Epic and Classical periods of the language, which are the best-attested periods and considered most typical of Ancient Greek. From the Hellenistic period ( c. 300 BC ), Ancient Greek was followed by Koine Greek , which is regarded as
1206-403: A traditional part of European and Asian cuisines and are used to make products such as agar , carrageenans , and other food additives . Chloroplasts probably evolved following an endosymbiotic event between an ancestral, photosynthetic cyanobacterium and an early eukaryotic phagotroph . This event (termed primary endosymbiosis ) is at the origin of the red and green algae (including
1273-510: A vowel or /n s r/ ; final stops were lost, as in γάλα "milk", compared with γάλακτος "of milk" (genitive). Ancient Greek of the classical period also differed in both the inventory and distribution of original PIE phonemes due to numerous sound changes, notably the following: The pronunciation of Ancient Greek was very different from that of Modern Greek . Ancient Greek had long and short vowels ; many diphthongs ; double and single consonants; voiced, voiceless, and aspirated stops ; and
1340-502: A worldwide distribution in various habitats; they generally prefer clean, high-flow streams with clear waters and rocky bottoms, but with some exceptions. A few freshwater species are found in black waters with sandy bottoms and even fewer are found in more lentic waters. Both marine and freshwater taxa are represented by free-living macroalgal forms and smaller endo/epiphytic/zoic forms, meaning they live in or on other algae, plants, and animals. In addition, some marine species have adopted
1407-421: Is C- phycocyanin . Reproduction is asexual by binary fission or formation of endospores . The group, consisting of a single order (Cyanidiales), split off from the other red algae more than a billion years ago. Three families, four genera, and nine species are known, but the total number of species is probably higher. They are primarily photoautotrophic, but heterotrophic and mixotrophic growth also occurs. After
SECTION 20
#17330931150591474-556: Is a literary form of Archaic Greek (derived primarily from Ionic and Aeolic) used in the epic poems , the Iliad and the Odyssey , and in later poems by other authors. Homeric Greek had significant differences in grammar and pronunciation from Classical Attic and other Classical-era dialects. The origins, early form and development of the Hellenic language family are not well understood because of
1541-418: Is added to stems beginning with consonants, and simply prefixes e (stems beginning with r , however, add er ). The quantitative augment is added to stems beginning with vowels, and involves lengthening the vowel: Some verbs augment irregularly; the most common variation is e → ei . The irregularity can be explained diachronically by the loss of s between vowels, or that of the letter w , which affected
1608-644: Is called 'East Greek'. Arcadocypriot apparently descended more closely from the Mycenaean Greek of the Bronze Age. Boeotian Greek had come under a strong Northwest Greek influence, and can in some respects be considered a transitional dialect, as exemplified in the poems of the Boeotian poet Pindar who wrote in Doric with a small Aeolic admixture. Thessalian likewise had come under Northwest Greek influence, though to
1675-448: Is considered by some linguists to have been closely related to Greek . Among Indo-European branches with living descendants, Greek is often argued to have the closest genetic ties with Armenian (see also Graeco-Armenian ) and Indo-Iranian languages (see Graeco-Aryan ). Ancient Greek differs from Proto-Indo-European (PIE) and other Indo-European languages in certain ways. In phonotactics , ancient Greek words could end only in
1742-812: Is estimated that more than half of all known species of microbial eukaryotes harbor red-alga-derived plastids. Red algae are divided into the Cyanidiophyceae , a class of unicellular and thermoacidophilic extremophiles found in sulphuric hot springs and other acidic environments, an adaptation partly made possible by horizontal gene transfers from prokaryotes, with about 1% of their genome having this origin, and two sister clades called SCRP ( Stylonematophyceae , Compsopogonophyceae , Rhodellophyceae and Porphyridiophyceae ) and BF ( Bangiophyceae and Florideophyceae ), which are found in both marine and freshwater environments. The BF are macroalgae, seaweed that usually do not grow to more than about 50 cm in length, but
1809-452: Is incomplete. Typically, a small pore is left in the middle of the newly formed partition. The pit connection is formed where the daughter cells remain in contact. Shortly after the pit connection is formed, cytoplasmic continuity is blocked by the generation of a pit plug, which is deposited in the wall gap that connects the cells. Connections between cells having a common parent cell are called primary pit connections. Because apical growth
1876-713: Is one of the most consumed red algae and is a source of iodine, protein, magnesium and calcium. Red algae's nutritional value is used for the dietary supplement of algas calcareas . China, Japan, Republic of Korea are the top producers of seaweeds. In East and Southeast Asia, agar is most commonly produced from Gelidium amansii . These rhodophytes are easily grown and, for example, nori cultivation in Japan goes back more than three centuries. Researchers in Australia discovered that limu kohu ( Asparagopsis taxiformis ) can reduce methane emissions in cattle . In one Hawaii experiment,
1943-522: Is supported by various structural and genetic similarities. Red algae have a long history of use as a source of nutritional, functional food ingredients and pharmaceutical substances. They are a source of antioxidants including polyphenols, and phycobiliproteins and contain proteins, minerals, trace elements, vitamins and essential fatty acids. Traditionally, red algae are eaten raw, in salads, soups, meal and condiments. Several species are food crops, in particular dulse ( Palmaria palmata ) and members of
2010-417: Is the isopod Idotea balthica. The trichogyne will continue to grow until it encounters a spermatium ; once it has been fertilized, the cell wall at its base progressively thickens, separating it from the rest of the carpogonium at its base. Upon their collision, the walls of the spermatium and carpogonium dissolve. The male nucleus divides and moves into the carpogonium; one half of the nucleus merges with
2077-425: Is the norm in red algae, most cells have two primary pit connections, one to each adjacent cell. Connections that exist between cells not sharing a common parent cell are labelled secondary pit connections. These connections are formed when an unequal cell division produced a nucleated daughter cell that then fuses to an adjacent cell. Patterns of secondary pit connections can be seen in the order Ceramiales . After
Red algae - Misplaced Pages Continue
2144-494: Is used for the red algae. No subdivisions are given; the authors say, "Traditional subgroups are artificial constructs, and no longer valid." Many subsequent studies provided evidence that is in agreement for monophyly in the Archaeplastida (including red algae). However, other studies have suggested Archaeplastida is paraphyletic . As of January 2011, the situation appears unresolved. Below are other published taxonomies of
2211-500: The Ediacaran Period. Thallophytes resembling coralline red algae are known from the late Proterozoic Doushantuo formation . Chromista and Alveolata algae (e.g., chrysophytes, diatoms, phaeophytes, dinophytes) seem to have evolved from bikonts that have acquired red algae as endosymbionts . According to this theory, over time these endosymbiont red algae have evolved to become chloroplasts. This part of endosymbiotic theory
2278-745: The Greek region of Macedonia during the last decades has brought to light documents, among which the first texts written in Macedonian , such as the Pella curse tablet , as Hatzopoulos and other scholars note. Based on the conclusions drawn by several studies and findings such as Pella curse tablet , Emilio Crespo and other scholars suggest that ancient Macedonian was a Northwest Doric dialect , which shares isoglosses with its neighboring Thessalian dialects spoken in northeastern Thessaly . Some have also suggested an Aeolic Greek classification. The Lesbian dialect
2345-501: The present , future , and imperfect are imperfective in aspect; the aorist , present perfect , pluperfect and future perfect are perfective in aspect. Most tenses display all four moods and three voices, although there is no future subjunctive or imperative. Also, there is no imperfect subjunctive, optative or imperative. The infinitives and participles correspond to the finite combinations of tense, aspect, and voice. The indicative of past tenses adds (conceptually, at least)
2412-699: The 10 complete genomes of red algae. One of the oldest fossils identified as a red alga is also the oldest fossil eukaryote that belongs to a specific modern taxon . Bangiomorpha pubescens , a multicellular fossil from arctic Canada , strongly resembles the modern red alga Bangia and occurs in rocks dating to 1.05 billion years ago. Two kinds of fossils resembling red algae were found sometime between 2006 and 2011 in well-preserved sedimentary rocks in Chitrakoot, central India. The presumed red algae lie embedded in fossil mats of cyanobacteria, called stromatolites, in 1.6 billion-year-old Indian phosphorite – making them
2479-1031: The 5th century BC. Ancient pronunciation cannot be reconstructed with certainty, but Greek from the period is well documented, and there is little disagreement among linguists as to the general nature of the sounds that the letters represent. /oː/ raised to [uː] , probably by the 4th century BC. Greek, like all of the older Indo-European languages , is highly inflected. It is highly archaic in its preservation of Proto-Indo-European forms. In ancient Greek, nouns (including proper nouns) have five cases ( nominative , genitive , dative , accusative , and vocative ), three genders ( masculine , feminine , and neuter ), and three numbers (singular, dual , and plural ). Verbs have four moods ( indicative , imperative , subjunctive , and optative ) and three voices (active, middle, and passive ), as well as three persons (first, second, and third) and various other forms. Verbs are conjugated through seven combinations of tenses and aspect (generally simply called "tenses"):
2546-490: The Archaic period of ancient Greek (see Homeric Greek for more details): Μῆνιν ἄειδε, θεά, Πηληϊάδεω Ἀχιλῆος οὐλομένην, ἣ μυρί' Ἀχαιοῖς ἄλγε' ἔθηκε, πολλὰς δ' ἰφθίμους ψυχὰς Ἄϊδι προΐαψεν ἡρώων, αὐτοὺς δὲ ἑλώρια τεῦχε κύνεσσιν οἰωνοῖσί τε πᾶσι· Διὸς δ' ἐτελείετο βουλή· ἐξ οὗ δὴ τὰ πρῶτα διαστήτην ἐρίσαντε Ἀτρεΐδης τε ἄναξ ἀνδρῶν καὶ δῖος Ἀχιλλεύς. The beginning of Apology by Plato exemplifies Attic Greek from
2613-563: The Assembling the Tree of Life Program. Porphyridiales Bangiales Some sources (such as Lee) place all red algae into the class "Rhodophyceae". (Lee's organization is not a comprehensive classification, but a selection of orders considered common or important.) A subphylum - Proteorhodophytina - has been proposed to encompass the existing classes Compsopogonophyceae , Porphyridiophyceae , Rhodellophyceae and Stylonematophyceae . This proposal
2680-590: The Classical period of ancient Greek. (The second line is the IPA , the third is transliterated into the Latin alphabet using a modern version of the Erasmian scheme .) Ὅτι [hóti Hóti μὲν men mèn ὑμεῖς, hyːmêːs hūmeîs, Cyanidiophyceae Cyanidiophyceae is a class of unicellular red algae within subdivision Cyanidiophytina , and contain a single plastid , one to three mitochondria ,
2747-465: The absence of chloroplast endoplasmic reticulum. The presence of the water-soluble pigments called phycobilins ( phycocyanobilin , phycoerythrobilin , phycourobilin and phycobiliviolin ), which are localized into phycobilisomes , gives red algae their distinctive color. Their chloroplasts contain evenly spaced and ungrouped thylakoids and contain the pigments chlorophyll a, α- and β-carotene, lutein and zeaxanthin. Their chloroplasts are enclosed in
Red algae - Misplaced Pages Continue
2814-550: The aorist. Following Homer 's practice, the augment is sometimes not made in poetry , especially epic poetry. The augment sometimes substitutes for reduplication; see below. Almost all forms of the perfect, pluperfect, and future perfect reduplicate the initial syllable of the verb stem. (A few irregular forms of perfect do not reduplicate, whereas a handful of irregular aorists reduplicate.) The three types of reduplication are: Irregular duplication can be understood diachronically. For example, lambanō (root lab ) has
2881-746: The asexual class Cyanidiophyceae , no terrestrial species exist, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity. Red algae form a distinct group characterized by eukaryotic cells without flagella and centrioles , chloroplasts without external endoplasmic reticulum or unstacked (stroma) thylakoids , and use phycobiliproteins as accessory pigments , which give them their red color. Despite their name, red algae can vary in color from bright green, soft pink, resembling brown algae, to shades of red and purple, and may be almost black at greater depths. Unlike green algae, red algae store sugars as food reserves outside
2948-419: The augment when it was word-initial. In verbs with a preposition as a prefix, the augment is placed not at the start of the word, but between the preposition and the original verb. For example, προσ(-)βάλλω (I attack) goes to προσ έ βαλoν in the aorist. However compound verbs consisting of a prefix that is not a preposition retain the augment at the start of the word: αὐτο(-)μολῶ goes to ηὐ τομόλησα in
3015-401: The carpogonium's nucleus. The polyamine spermine is produced, which triggers carpospore production. Spermatangia may have long, delicate appendages, which increase their chances of "hooking up". They display alternation of generations . In addition to a gametophyte generation, many have two sporophyte generations, the carposporophyte -producing carpospores , which germinate into
3082-438: The center of Greek scholarship, this division of people and language is quite similar to the results of modern archaeological-linguistic investigation. One standard formulation for the dialects is: West vs. non-West Greek is the strongest-marked and earliest division, with non-West in subsets of Ionic-Attic (or Attic-Ionic) and Aeolic vs. Arcadocypriot, or Aeolic and Arcado-Cypriot vs. Ionic-Attic. Often non-West
3149-539: The chloroplasts as floridean starch , a type of starch that consists of highly branched amylopectin without amylose . Most red algae are multicellular , macroscopic, and reproduce sexually . The life history of red algae is typically an alternation of generations that may have three generations rather than two. Coralline algae , which secrete calcium carbonate and play a major role in building coral reefs , belong there. Red algae such as Palmaria palmata (dulse) and Porphyra species ( laver / nori / gim ) are
3216-611: The dialect of Sparta ), and Northern Peloponnesus Doric (including Corinthian ). All the groups were represented by colonies beyond Greece proper as well, and these colonies generally developed local characteristics, often under the influence of settlers or neighbors speaking different Greek dialects. After the conquests of Alexander the Great in the late 4th century BC, a new international dialect known as Koine or Common Greek developed, largely based on Attic Greek , but with influence from other dialects. This dialect slowly replaced most of
3283-438: The environmental conditions like change in pH, the salinity of medium, change in light intensity, nutrient limitation etc. When the salinity of the medium increases the production of floridoside is increased in order to prevent water from leaving the algal cells. Pit connections and pit plugs are unique and distinctive features of red algae that form during the process of cytokinesis following mitosis . In red algae, cytokinesis
3350-599: The first massive gene loss in the common ancestor of all red algae, where ca. 25% of the genes were lost, a second gene loss occurred in the ancestor of Cyanidiophyceae, where additional 18% of the genes were lost. Since then, some gene gains and minor gene losses have taken place independently in the Cyanidiaceae and Galdieriaceae, leading to genetic diversification between the two groups, with Galdieriaceae occupying more diverse and varied niches in extreme environments than Cyanidiaceae. This Rhodophyta -related article
3417-663: The forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek ( c. 1400–1200 BC ), Dark Ages ( c. 1200–800 BC ), the Archaic or Epic period ( c. 800–500 BC ), and the Classical period ( c. 500–300 BC ). Ancient Greek was the language of Homer and of fifth-century Athenian historians, playwrights, and philosophers . It has contributed many words to English vocabulary and has been
SECTION 50
#17330931150593484-435: The genus Porphyra , variously known as nori (Japan), gim (Korea), zicai 紫菜 (China), and laver (British Isles). Red algal species such as Gracilaria and Laurencia are rich in polyunsaturated fatty acids (eicopentaenoic acid, docohexaenoic acid, arachidonic acid ) and have protein content up to 47% of total biomass. Where a big portion of world population is getting insufficient daily iodine intake,
3551-556: The historical Dorians . The invasion is known to have displaced population to the later Attic-Ionic regions, who regarded themselves as descendants of the population displaced by or contending with the Dorians. The Greeks of this period believed there were three major divisions of all Greek people – Dorians, Aeolians, and Ionians (including Athenians), each with their own defining and distinctive dialects. Allowing for their oversight of Arcadian, an obscure mountain dialect, and Cypriot, far from
3618-472: The historical circumstances of the times imply that the overall groups already existed in some form. Scholars assume that major Ancient Greek period dialect groups developed not later than 1120 BC, at the time of the Dorian invasions —and that their first appearances as precise alphabetic writing began in the 8th century BC. The invasion would not be "Dorian" unless the invaders had some cultural relationship to
3685-513: The land plants or Embryophytes which emerged within them) and the glaucophytes , which together make up the oldest evolutionary lineages of photosynthetic eukaryotes, the Archaeplastida . A secondary endosymbiosis event involving an ancestral red alga and a heterotrophic eukaryote resulted in the evolution and diversification of several other photosynthetic lineages such as Cryptophyta , Haptophyta , Stramenopiles (or Heterokontophyta) , and Alveolata . In addition to multicellular brown algae, it
3752-452: The living cell produces a layer of wall material that seals off the plug. The pit connections have been suggested to function as structural reinforcement, or as avenues for cell-to-cell communication and transport in red algae, however little data supports this hypothesis. The reproductive cycle of red algae may be triggered by factors such as day length. Red algae reproduce sexually as well as asexually. Asexual reproduction can occur through
3819-499: The older dialects, although the Doric dialect has survived in the Tsakonian language , which is spoken in the region of modern Sparta. Doric has also passed down its aorist terminations into most verbs of Demotic Greek . By about the 6th century AD, the Koine had slowly metamorphosed into Medieval Greek . Phrygian is an extinct Indo-European language of West and Central Anatolia , which
3886-466: The oldest plant-like fossils ever found by about 400 million years. Red algae are important builders of limestone reefs. The earliest such coralline algae, the solenopores , are known from the Cambrian period. Other algae of different origins filled a similar role in the late Paleozoic , and in more recent reefs. Calcite crusts that have been interpreted as the remains of coralline red algae, date to
3953-487: The perfect stem eilēpha (not * lelēpha ) because it was originally slambanō , with perfect seslēpha , becoming eilēpha through compensatory lengthening. Reduplication is also visible in the present tense stems of certain verbs. These stems add a syllable consisting of the root's initial consonant followed by i . A nasal stop appears after the reduplication in some verbs. The earliest extant examples of ancient Greek writing ( c. 1450 BC ) are in
4020-526: The polysaccharides agarose and agaropectin that can be extracted from the cell walls as agar by boiling. The internal walls are mostly cellulose. They also have the most gene-rich plastid genomes known. Red algae do not have flagella and centrioles during their entire life cycle. The distinguishing characters of red algal cell structure include the presence of normal spindle fibres, microtubules, un-stacked photosynthetic membranes, phycobilin pigment granules, pit connection between cells, filamentous genera, and
4087-417: The production of spores and by vegetative means (fragmentation, cell division or propagules production). Red algae lack motile sperm . Hence, they rely on water currents to transport their gametes to the female organs – although their sperm are capable of "gliding" to a carpogonium 's trichogyne . Animals also help with the dispersal and fertilization of the gametes. The first species discovered to do so
SECTION 60
#17330931150594154-566: The red algae using molecular and traditional alpha taxonomic data; however, the taxonomy of the red algae is still in a state of flux (with classification above the level of order having received little scientific attention for most of the 20th century). A major research initiative to reconstruct the Red Algal Tree of Life (RedToL) using phylogenetic and genomic approach is funded by the National Science Foundation as part of
4221-481: The reduction reached 77%. The World Bank predicted the industry could be worth ~$ 1.1 billion by 2030. As of 2024, preparation included three stages of cultivation and drying. Australia's first commercial harvest was in 2022. Agriculture accounts for 37% of the world’s anthropogenic methane emissions. One cow produces between 154 to 264 pounds of methane/yr. Ancient Greek language Ancient Greek ( Ἑλληνῐκή , Hellēnikḗ ; [hellɛːnikɛ́ː] ) includes
4288-517: The syllabic script Linear B . Beginning in the 8th century BC, however, the Greek alphabet became standard, albeit with some variation among dialects. Early texts are written in boustrophedon style, but left-to-right became standard during the classic period. Modern editions of ancient Greek texts are usually written with accents and breathing marks , interword spacing , modern punctuation , and sometimes mixed case , but these were all introduced later. The beginning of Homer 's Iliad exemplifies
4355-475: Was Aeolic. For example, fragments of the works of the poet Sappho from the island of Lesbos are in Aeolian. Most of the dialect sub-groups listed above had further subdivisions, generally equivalent to a city-state and its surrounding territory, or to an island. Doric notably had several intermediate divisions as well, into Island Doric (including Cretan Doric ), Southern Peloponnesus Doric (including Laconian ,
4422-518: Was formerly attributed to the presence of pigments (such as phycoerythrin ) that would permit red algae to inhabit greater depths than other macroalgae by chromatic adaption, recent evidence calls this into question (e.g. the discovery of green algae at great depth in the Bahamas). Some marine species are found on sandy shores, while most others can be found attached to rocky substrata. Freshwater species account for 5% of red algal diversity, but they also have
4489-529: Was made on the basis of the analysis of the plastid genomes. Over 7,000 species are currently described for the red algae, but the taxonomy is in constant flux with new species described each year. The vast majority of these are marine with about 200 that live only in fresh water . Some examples of species and genera of red algae are: Red algal morphology is diverse ranging from unicellular forms to complex parenchymatous and non- parenchymatous thallus. Red algae have double cell walls . The outer layers contain
#58941