Order ( Latin : ordo ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy . It is classified between family and class . In biological classification , the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes . An immediately higher rank, superorder , is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families.
23-542: See below Sphenosuchia is a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Middle Jurassic . Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms , a group which includes all living crocodilians . The earliest known members of the group (i.e. Hesperosuchus ) are early Norian in age, found in
46-461: A cohors (plural cohortes ). Some of the plant families still retain the names of Linnaean "natural orders" or even the names of pre-Linnaean natural groups recognized by Linnaeus as orders in his natural classification (e.g. Palmae or Labiatae ). Such names are known as descriptive family names. In the field of zoology , the Linnaean orders were used more consistently. That is,
69-574: A big immobile female gamete ( egg cell ). The egg cell secretes a pheromone, dictyotene , to attract the sperm cell. After the fertilization between the two gametes, the resulting diploid zygote grows into the sporophyte generation. On their surface, modified sporangia typically produce through meiosis four haploid non-flagellated aplanospores , but a few genera produce eight spores per sporangium ( Lobophora , Zonaria ) or flagellated spores ( Exallosorus ), two features considered primitive. The spores, while naked are released through
92-509: A capital letter. For some groups of organisms, their orders may follow consistent naming schemes . Orders of plants , fungi , and algae use the suffix -ales (e.g. Dictyotales ). Orders of birds and fishes use the Latin suffix -iformes meaning 'having the form of' (e.g. Passeriformes ), but orders of mammals and invertebrates are not so consistent (e.g. Artiodactyla , Actiniaria , Primates ). For some clades covered by
115-570: A distinct rank of biological classification having its own distinctive name (and not just called a higher genus ( genus summum )) was first introduced by the German botanist Augustus Quirinus Rivinus in his classification of plants that appeared in a series of treatises in the 1690s. Carl Linnaeus was the first to apply it consistently to the division of all three kingdoms of nature (then minerals , plants , and animals ) in his Systema Naturae (1735, 1st. Ed.). For plants, Linnaeus' orders in
138-514: A single apical cell . One genus in this order, Padina , is the only calcareous member of the brown algae. Dictyotales are an order of brown algae (Phaeophyceae), a lineage of multicellular photosynthetic protists composed by a thallus that has a certain level of tissue differentiation . The reference organism of Dictyotales used to study their general characteristics is Dictyota dichotoma . Dictyotales are composed of flattened, parenchymatous thalli . They display apical growth:
161-591: A single apical cell forms the flattened thallus , the vegetative part of the organism, through mitosis . The mature thallus is composed of three layers: one middle layer of large cells lacking chloroplasts , surrounded by two layers of small cells packed densely with chloroplasts lacking pyrenoids . Some taxa exhibit blue-green iridescence when submerged. Some species of Dictyopteris and Spatoglossum have cellular vacuoles with very low pH (between 0.5 and 0.9). Dictyotales displays, like other brown algae , an isomorphic alternation of two generations :
184-419: Is determined by a taxonomist , as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with
207-1250: Is due in part to its ability to asexually reproduce from fragments created by " biotic and abiotic disturbances". Dictyotales contains the only calcareous genus of brown algae , Padina . Its margins contain a layer of apical cells with hairs that create a microenvironment where aragonite nucleation occurs, if isolated from the water flow. The order Dictyotales contains only one family , Dictyotaceae , described by French biologist Jean Vincent Félix Lamouroux , and later validly published by Belgian botanist Barthélemy Charles Joseph Dumortier in 1822. Originally, this order also included two provisional families, each with one genus: Scoresbyellaceae , described by Australian phycologist Hugh Bryan Spencer Womersley in 1987, and Dictyotopsidaceae , described by phycologist Bruce M. Allender in 1980. Posterior phylogenetic analyses showed that both families branch within Dictyotaceae, thus they were synonymized . The latest revision of brown algae , published in 2014, recognizes 19 genera within Dictyotales, as well as 7 genera that have been synonymized with
230-528: The International Code of Zoological Nomenclature , several additional classifications are sometimes used, although not all of these are officially recognized. In their 1997 classification of mammals , McKenna and Bell used two extra levels between superorder and order: grandorder and mirorder . Michael Novacek (1986) inserted them at the same position. Michael Benton (2005) inserted them between superorder and magnorder instead. This position
253-815: The Systema Naturae and the Species Plantarum were strictly artificial, introduced to subdivide the artificial classes into more comprehensible smaller groups. When the word ordo was first consistently used for natural units of plants, in 19th-century works such as the Prodromus Systematis Naturalis Regni Vegetabilis of Augustin Pyramus de Candolle and the Genera Plantarum of Bentham & Hooker, it indicated taxa that are now given
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#1732802029212276-446: The gametophytes (the haploid generation), which generate gametes through mitosis ; and the sporophytes (the diploid generation), which generate spores through meiosis , both of them similar in shape and structure. The gametophytes form sex organs (female oogonia and male antheridia ) in sori . Both sex organs develop from surface cells. The reproduction is oogamous , with a small and mobile male gamete ( sperm cell ) and
299-915: The Blue Mesa Member of the Chinle Formation . Only one sphenosuchian is currently known from the Middle Jurassic, Junggarsuchus , from the Junggar Basin ( Shishugou Formation ) of China during either the Bathonian or the Callovian (~165 Ma) age, and the Hallopodidae are known from the Late Jurassic of North America. The monophyly of the group is debated, although several synapomorphies characterize
322-454: The clade, including extremely slender limbs, a compact carpus and an elongate coracoid process . In 2002, Clark and Sues found a possible sphenosuchian clade of Dibothrosuchus , Sphenosuchus , and possibly Hesperosuchus and Saltoposuchus , with several other genera in unresolved positions ( Kayentasuchus , Litargosuchus , Pseudhesperosuchus , and Terrestrisuchus ). More recently, however, Clark et al. (2004) argued for
345-638: The gelatinized apex of the sporangium. Soon after, they grow a cellulose wall and grow into gametophytes. Dictyotales are most diverse in tropical and subtropical waters, but extend into temperate regions. They are one of the few brown algal orders whose species can form a conspicuous, even dominant component of tropical and temperate marine floras. Their ecological success is often linked to their ability to deter grazers in habitats subject to strong grazing pressure, making them an important competitor of corals and other sessile benthic life in many coastal ecosystems. Some species, in particular within
368-520: The genus Dictyota , produce terpenoids (such as pachydictyol ) that inhibit grazing by herbivorous amphipods , sea urchins and fish . The species Lobophora variegata produces a cyclic lactone , lobophorolide , that in low concentrations is an active compound against pathogenic and saprophytic marine fungi . Dictyota dominates 70% of the benthos biomass in the Florida Keys reef tract. The successful spread of this alga
391-486: The green bracket. CM 73372 Hesperosuchus Dromicosuchus Sphenosuchus Dibothrosuchus Terrestrisuchus Litargosuchus Kayentasuchus Orthosuchus Protosuchus Alligator [REDACTED] Switzerland [REDACTED] UK Trossingen Formation Lossiemouth Sandstone [REDACTED] [REDACTED] [REDACTED] [REDACTED] Suborder What does and does not belong to each order
414-708: The orders in the zoology part of the Systema Naturae refer to natural groups. Some of his ordinal names are still in use, e.g. Lepidoptera (moths and butterflies) and Diptera (flies, mosquitoes, midges, and gnats). In virology , the International Committee on Taxonomy of Viruses 's virus classification includes fifteen taxomomic ranks to be applied for viruses , viroids and satellite nucleic acids : realm , subrealm , kingdom , subkingdom, phylum , subphylum , class, subclass, order, suborder, family, subfamily , genus, subgenus , and species. There are currently fourteen viral orders, each ending in
437-460: The paraphyly of the group, contending that morphological characters were secondarily lost in more highly derived crocodylomorphs. Further analysis and study is required before the group's monophyly is resolved with certainty — a perfect phylogenetic analysis is, at present, impossible due to a paucity of fossil remains demonstrating phylogenetically informative characters. Below is a cladogram modified from Nesbitt (2011). Sphenosuchians are marked by
460-564: The precursor of the currently used International Code of Nomenclature for algae, fungi, and plants . In the first international Rules of botanical nomenclature from the International Botanical Congress of 1905, the word family ( familia ) was assigned to the rank indicated by the French famille , while order ( ordo ) was reserved for a higher rank, for what in the 19th century had often been named
483-502: The rank of family (see ordo naturalis , ' natural order '). In French botanical publications, from Michel Adanson 's Familles naturelles des plantes (1763) and until the end of the 19th century, the word famille (plural: familles ) was used as a French equivalent for this Latin ordo . This equivalence was explicitly stated in the Alphonse Pyramus de Candolle 's Lois de la nomenclature botanique (1868),
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#1732802029212506-566: The suffix -virales . Dictyotales 21 genera Dictyotales (from Greek diktyotos 'netlike') is a large order in the brown algae (class Phaeophyceae ) containing the single family Dictyotaceae . Members of this order generally prefer warmer (tropical to subtropical) waters than other brown algae, and are prevalent in tropical and subtropical waters thanks to their many chemical defenses to ward off grazers . They display an isomorphic haplodiploid life cycle and are characterized by vegetative growth through
529-418: Was adopted by Systema Naturae 2000 and others. In botany , the ranks of subclass and suborder are secondary ranks pre-defined as respectively above and below the rank of order. Any number of further ranks can be used as long as they are clearly defined. The superorder rank is commonly used, with the ending -anae that was initiated by Armen Takhtajan 's publications from 1966 onwards. The order as
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