The calcareous sponges of class Calcarea are members of the animal phylum Porifera, the cellular sponges. They are characterized by spicules made out of calcium carbonate in the form of calcite or aragonite. While the spicules in most species have three points, in some species they have either two or four points. All sponges in this class are marine, while they are distributed worldwide, most are found in shallow tropical waters. Like all other sponges, they are sedentary filter feeders. All three sponge body plans are represented within class Calcarea: asconoid and leuconoid. Calcareous sponges are small, measuring less than 10 cm in height, drab in colour. However, a few brightly coloured species are known. Calcareous sponges vary from radially symmetrical vase-shaped body types to colonies made up of a meshwork of thin tubes, or irregular massive forms; the skeleton has either honeycomb structure. Of the 15,000 or so species of Porifera that exist, only 400 of those are calcareans. Calcarean sponges first appeared during the Cambrian, their diversity was greatest during the Cretaceous period.
Recent molecular analysis suggests the class Calcarea should be designated as a phylum, in particular the first to have diverged in the Animalia. The calcareous sponges are divided into two subclasses and six orders: Class Calcarea Subclass Calcinea Order Clathrinida Order Murrayonida Subclass Calcaronea Order Baerida Order Leucosolenida Order Lithonida Order Pharetronida† Barnes, Robert D.. Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. P. 104. ISBN 0-03-056747-5. UCMP: Calcarea
Animals are multicellular eukaryotic organisms that form the biological kingdom Animalia. With few exceptions, animals consume organic material, breathe oxygen, are able to move, can reproduce sexually, grow from a hollow sphere of cells, the blastula, during embryonic development. Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million animal species in total. Animals range in length from 8.5 millionths of a metre to 33.6 metres and have complex interactions with each other and their environments, forming intricate food webs. The category includes humans, but in colloquial use the term animal refers only to non-human animals; the study of non-human animals is known as zoology. Most living animal species are in the Bilateria, a clade whose members have a bilaterally symmetric body plan; the Bilateria include the protostomes—in which many groups of invertebrates are found, such as nematodes and molluscs—and the deuterostomes, containing the echinoderms and chordates.
Life forms interpreted. Many modern animal phyla became established in the fossil record as marine species during the Cambrian explosion which began around 542 million years ago. 6,331 groups of genes common to all living animals have been identified. Aristotle divided animals into those with those without. Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809. In 1874, Ernst Haeckel divided the animal kingdom into the multicellular Metazoa and the Protozoa, single-celled organisms no longer considered animals. In modern times, the biological classification of animals relies on advanced techniques, such as molecular phylogenetics, which are effective at demonstrating the evolutionary relationships between animal taxa. Humans make use of many other animal species for food, including meat and eggs. Dogs have been used in hunting, while many aquatic animals are hunted for sport.
Non-human animals have appeared in art from the earliest times and are featured in mythology and religion. The word "animal" comes from the Latin animalis, having soul or living being; the biological definition includes all members of the kingdom Animalia. In colloquial usage, as a consequence of anthropocentrism, the term animal is sometimes used nonscientifically to refer only to non-human animals. Animals have several characteristics. Animals are eukaryotic and multicellular, unlike bacteria, which are prokaryotic, unlike protists, which are eukaryotic but unicellular. Unlike plants and algae, which produce their own nutrients animals are heterotrophic, feeding on organic material and digesting it internally. With few exceptions, animals breathe oxygen and respire aerobically. All animals are motile during at least part of their life cycle, but some animals, such as sponges, corals and barnacles become sessile; the blastula is a stage in embryonic development, unique to most animals, allowing cells to be differentiated into specialised tissues and organs.
All animals are composed of cells, surrounded by a characteristic extracellular matrix composed of collagen and elastic glycoproteins. During development, the animal extracellular matrix forms a flexible framework upon which cells can move about and be reorganised, making the formation of complex structures possible; this may be calcified, forming structures such as shells and spicules. In contrast, the cells of other multicellular organisms are held in place by cell walls, so develop by progressive growth. Animal cells uniquely possess the cell junctions called tight junctions, gap junctions, desmosomes. With few exceptions—in particular, the sponges and placozoans—animal bodies are differentiated into tissues; these include muscles, which enable locomotion, nerve tissues, which transmit signals and coordinate the body. There is an internal digestive chamber with either one opening or two openings. Nearly all animals make use of some form of sexual reproduction, they produce haploid gametes by meiosis.
These fuse to form zygotes, which develop via mitosis into a hollow sphere, called a blastula. In sponges, blastula larvae swim to a new location, attach to the seabed, develop into a new sponge. In most other groups, the blastula undergoes more complicated rearrangement, it first invaginates to form a gastrula with a digestive chamber and two separate germ layers, an external ectoderm and an internal endoderm. In most cases, a third germ layer, the mesoderm develops between them; these germ layers differentiate to form tissues and organs. Repeated instances of mating with a close relative during sexual reproduction leads to inbreeding depression within a population due to the increased prevalence of harmful recessive traits. Animals have evolved numerous mechanisms for avoiding close inbreeding. In some species, such as the splendid fairywren, females benefit by mating with multiple males, thus producing more offspring of higher genetic quality; some animals are capable of asexual reproduction, which results
Fossilworks is a portal which provides query and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. Fossilworks is housed at Macquarie University, it includes many analysis and data visualization tools included in the Paleobiology Database. "Fossilworks". Retrieved 2010-04-08
Wikispecies is a wiki-based online project supported by the Wikimedia Foundation. Its aim is to create a comprehensive free content catalogue of all species. Jimmy Wales stated that editors are not required to fax in their degrees, but that submissions will have to pass muster with a technical audience. Wikispecies is available under the GNU Free Documentation License and CC BY-SA 3.0. Started in September 2004, with biologists across the world invited to contribute, the project had grown a framework encompassing the Linnaean taxonomy with links to Wikipedia articles on individual species by April 2005. Benedikt Mandl co-ordinated the efforts of several people who are interested in getting involved with the project and contacted potential supporters in early summer 2004. Databases were evaluated and the administrators contacted, some of them have agreed on providing their data for Wikispecies. Mandl defined two major tasks: Figure out how the contents of the data base would need to be presented—by asking experts, potential non-professional users and comparing that with existing databases Figure out how to do the software, which hardware is required and how to cover the costs—by asking experts, looking for fellow volunteers and potential sponsorsAdvantages and disadvantages were discussed by the wikimedia-I mailing list.
The board of directors of the Wikimedia Foundation voted by 4 to 0 in favor of the establishment of a Wikispecies. The project is hosted at species.wikimedia.org. It was merged to a sister project of Wikimedia Foundation on September 14, 2004. On October 10, 2006, the project exceeded 75,000 articles. On May 20, 2007, the project exceeded 100,000 articles with a total of 5,495 registered users. On September 8, 2008, the project exceeded 150,000 articles with a total of 9,224 registered users. On October 23, 2011, the project reached 300,000 articles. On June 16, 2014, the project reached 400,000 articles. On January 7, 2017, the project reached 500,000 articles. On October 30, 2018, the project reached 600,000 articles, a total of 1.12 million pages. Wikispecies comprises taxon pages, additionally pages about synonyms, taxon authorities, taxonomical publications, institutions or repositories holding type specimen. Wikispecies asks users to use images from Wikimedia Commons. Wikispecies does not allow the use of content.
All Species Foundation Catalogue of Life Encyclopedia of Life Tree of Life Web Project List of online encyclopedias The Plant List Wikispecies, The free species directory that anyone can edit Species Community Portal The Wikispecies Charter, written by Wales
Sponges, the members of the phylum Porifera, are a basal Metazoa clade as a sister of the Diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells; the branch of zoology that studies sponges is known as spongiology. Sponges have unspecialized cells that can transform into other types and that migrate between the main cell layers and the mesohyl in the process. Sponges do not have digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the common ancestor of all animals, making them the sister group of all other animals; the term sponge derives from the Ancient Greek word σπόγγος. Sponges are similar to other animals in that they are multicellular, lack cell walls and produce sperm cells.
Unlike other animals, they lack true organs. Some of them are radially symmetrical; the shapes of their bodies are adapted for maximal efficiency of water flow through the central cavity, where it deposits nutrients, leaves through a hole called the osculum. Many sponges have internal skeletons of spongin and/or spicules of calcium carbonate or silicon dioxide. All sponges are sessile aquatic animals. Although there are freshwater species, the great majority are marine species, ranging from tidal zones to depths exceeding 8,800 m. While most of the 5,000–10,000 known species feed on bacteria and other food particles in the water, some host photosynthesizing microorganisms as endosymbionts and these alliances produce more food and oxygen than they consume. A few species of sponge that live in food-poor environments have become carnivores that prey on small crustaceans. Most species use sexual reproduction, releasing sperm cells into the water to fertilize ova that in some species are released and in others are retained by the "mother".
The fertilized eggs form larvae to settle. Sponges are known for regenerating from fragments that are broken off, although this only works if the fragments include the right types of cells. A few species reproduce by budding; when conditions deteriorate, for example as temperatures drop, many freshwater species and a few marine ones produce gemmules, "survival pods" of unspecialized cells that remain dormant until conditions improve and either form new sponges or recolonize the skeletons of their parents. The mesohyl functions as an endoskeleton in most sponges, is the only skeleton in soft sponges that encrust hard surfaces such as rocks. More the mesohyl is stiffened by mineral spicules, by spongin fibers or both. Demosponges use spongin, in many species, silica spicules and in some species, calcium carbonate exoskeletons. Demosponges constitute about 90% of all known sponge species, including all freshwater ones, have the widest range of habitats. Calcareous sponges, which have calcium carbonate spicules and, in some species, calcium carbonate exoskeletons, are restricted to shallow marine waters where production of calcium carbonate is easiest.
The fragile glass sponges, with "scaffolding" of silica spicules, are restricted to polar regions and the ocean depths where predators are rare. Fossils of all of these types have been found in rocks dated from 580 million years ago. In addition Archaeocyathids, whose fossils are common in rocks from 530 to 490 million years ago, are now regarded as a type of sponge; the single-celled choanoflagellates resemble the choanocyte cells of sponges which are used to drive their water flow systems and capture most of their food. This along with phylogenetic studies of ribosomal molecules have been used as morphological evidence to suggest sponges are the sister group to the rest of animals; some studies have shown that sponges do not form a monophyletic group, in other words do not include all and only the descendants of a common ancestor. Recent phylogenetic analyses suggest that comb jellies rather than sponges are the sister group to the rest of animals; the few species of demosponge that have soft fibrous skeletons with no hard elements have been used by humans over thousands of years for several purposes, including as padding and as cleaning tools.
By the 1950s, these had been overfished so that the industry collapsed, most sponge-like materials are now synthetic. Sponges and their microscopic endosymbionts are now being researched as possible sources of medicines for treating a wide range of diseases. Dolphins have been observed using sponges as tools while foraging. Sponges constitute the phylum Porifera, have been defined as sessile metazoans that have water intake and outlet openings connected by chambers lined with choanocytes, cells with whip-like flagella. However, a few carnivorous sponges have lost the choanocytes. All known living sponges can remold their bodies, as most types of their cells can move within their bodies and a few can change from one type to another. If a few sponges are able to produce mucus – which acts as a microbial barrier in all other animals – no sponge with the ability to secrete a functional mucus layer has been recorded. Without such a mucus layer their living tissue is covered by a layer of microbial symbionts, which can contribute up to 40–50% of the sponge wet mass.
This inability to prevent microbes from penetrating their porous tissue could be a major reason why they have never evolved a more complex anatomy. Like cnidarians (jellyfish, e
An umbel is an inflorescence that consists of a number of short flower stalks which spread from a common point, somewhat like umbrella ribs. The word was coined in botany in the 1590s, from Latin umbella "parasol, sunshade"; the arrangement can vary from being flat topped to spherical. Umbels can compound; the secondary umbels of compound umbels are known as umbellets. A small umbel is called an umbellule; the arrangement of the inflorescence in umbels is referred to as umbellate, or subumbellate. Umbels are a characteristic of plants such as carrot, parsley and fennel in the family Apiaceae. An umbel is a type of indeterminate inflorescence. A compressed cyme, a determinate inflorescence, is called umbelliform if it resembles an umbel. Hinderer, Walter. "Differentiation of metabolic pathways in the umbel of Daucus carota". Phytochemistry. 22: 2417–2420. Doi:10.1016/0031-942280131-9. ISSN 0031-9422. Toben, H.-M.. Journal of Phytopathology. 144: 169–178. Doi:10.1111/j.1439-0434.1996.tb01510.x. ISSN 0931-1785.
Peterson, L. E.. C.. "Umbel Initiation and Stem Elongation in FennelInitiated by Photoperiod". Journal of Essential Oil Research. 5: 37–43. Doi:10.1080/10412905.1993.9698168. ISSN 1041-2905
An anastomosis is a connection or opening between two things that are diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be abnormal; the reestablishment of an anastomosis that had become blocked is called a reanastomosis. Anastomoses that are abnormal, whether congenital or acquired, are called fistulas; the term is used in medicine, mycology, geology and architecture. Anastomosis: medical or Modern Latin, from Greek ἀναστόμωσις, anastomosis, "outlet, opening", Gr ana- "up, on, upon", stoma "mouth", "to furnish with a mouth", thus the - stom - syllable is cognate with that of stoma in stoma in medicine. An anastomosis is the connection of two divergent structures, it refers to connections between blood vessels or between other tubular structures such as loops of intestine. In circulatory anastomoses, many arteries anastomose with each other; the circulatory anastomosis is further divided into venous anastomosis. Arterial anastomosis includes potential arterial anastomosis.
Anastomoses form alternative routes around capillary beds in areas that don't need a large blood supply, thus helping regulate systemic blood flow. An example of surgical anastomosis occurs when a segment of intestine, blood vessel, or any other structure are connected together. Examples include Roux-en-Y anastomosis or ureteroureterostomy. Surgical anastamosis techniques include Linear Stapled Anastomosis, Hand Sewn Anastomosis, End-to-End Anastomosis. Anastomosis can with an anastomosis assist device. Studies have been performed comparing various anastomosis approaches taking into account surgical "time and cost, postoperative anastomotic bleeding and stricture". Pathological anastomosis results from trauma or disease and may involve veins, arteries, or intestines; these are referred to as fistulas. In the cases of veins or arteries, traumatic fistulas occur between artery and vein. Traumatic intestinal fistulas occur between two loops of intestine or intestine and skin. Portacaval anastomosis, by contrast, is an anastomosis between a vein of the portal circulation and a vein of the systemic circulation, which allows blood to bypass the liver in patients with portal hypertension resulting in hemorrhoids, esophageal varices, or caput medusae.
In evolution, anastomosis is a recombination of evolutionary lineage. Conventional accounts of evolutionary lineage present themselves as the simple branching out of species into novel forms. Under anastomosis, species might recombine after initial branching out, such as in the case of recent research that shows that ancestral populations along human and chimpanzee lineages may have interbred after an initial branching event; the concept of anastomosis applies to the theory of symbiogenesis, in which new species emerge from the formation of novel symbiotic relationships. In mycology, anastomosis is the fusion between branches of the different hyphae. Hence the bifurcating fungal hyphae can form true reticulating networks. By sharing materials in the form of dissolved ions and nucleotides, the fungus maintains bidirectional communication with itself; the fungal network might begin from several origins. Once encountering the tip of another expanding, exploring self, the tips press against each other in pheromonal recognition or by an unknown recognition system, fusing to form a genetic singular clonal colony that can cover hectares called a genet or just microscopical areas.
For fungi, anastomosis is a component of reproduction. In some fungi, two different haploid mating types -- -- merge. Somatically, they form a morphologically similar mycelial wave front that continues to grow and explore; the significant difference, is that each septated unit is binucleate, containing two unfused nuclei, i.e. one from each parent that undergoes karyogamy and meiosis to complete the sexual cycle. The term "anastomosing" is used for mushroom gills which interlink and separate to form a network. In geology, anastomosis refers to quartz veins displaying this property, related to shearing in metamorphic regions. Anastomosing streams consist of multiple channels that divide and reconnect and are separated by semi-permanent banks formed of cohesive material, such that they are unlikely to migrate from one channel position to another, they can be confused with braiding, the splitting of a river by sand bars or hard rocks and some definitions require that an anastomosing river be made up of interconnected channels that enclose floodbasins.
Rivers with anastomosed reaches include the Magdalena River in Colombia, the upper Columbia River in British Columbia and the upper Narew River in Poland. The term anabranch has been used for segments of anastamosing rivers