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 "Pennatulida" from Ernst Haeckel's Kunstformen der Natur, 1904
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Sea pens are colonial marine cnidarians belonging to the order Pennatulacea. Ernst Heinrich Philipp August Haeckel ( February 16, 1834 — August 9, 1919)also written von Haeckel, was an eminent German Kunstformen der Natur ( German: Art Forms of Nature) is a book of lithographic and Autotype prints by German biologist Cnidaria (naɪˈdɛəriə is a phylum containing some 9000 Species of Animals found exclusively in aquatic mostly marine, environments Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many Alcyonaria (also known as Octocorallia, as they have 8-fold symmetry is a subclass of the class Anthozoa within the phylum Cnidaria. Addison Emery Verrill (1839 Greenwood Maine – 1926 Santa Barbara California) was an American Zoologist. In Biological classification, family ( Latin Cnidaria (naɪˈdɛəriə is a phylum containing some 9000 Species of Animals found exclusively in aquatic mostly marine, environments There are 14 families within the order; they are thought to have a cosmopolitan distribution in tropical and temperate waters worldwide. In Biogeography, a Biological category of living things is said to have cosmopolitan distribution if this category can be found almost anywhere around the world Sea pens are grouped with the octocorals ("soft corals"), together with sea whips and sea feathers. Alcyonaria (also known as Octocorallia, as they have 8-fold symmetry is a subclass of the class Anthozoa within the phylum Cnidaria. Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many
Although named after their feather-like appearance reminiscent of antique quill pens, only sea pen species belonging to the suborder Subselliflorae live up to the comparison. Quill is a high level object oriented Programming language created by the Dutch software company Quintiq. Those belonging to the much larger suborder Sessiliflorae lack feathery structures and grow in club-like or radiating forms. The latter suborder includes what are commonly known as sea pansies.
As octocorals, sea pens are composed of physiologic structures called polyps (which look somewhat like miniature sea anemones), each with eight tentacles. In Zoology, a polyp is one of two forms of individuals found in many species of Cnidarians The two are the polyp or hydroid and the medusa. Sea anemones are a group of water dwelling predatory animals of the order Actiniaria; they are named after the Anemone, a terrestrial Flower Tentacles can refer to the elongated flexible organs that are present in some animals especially Invertebrates and sometimes to the hairs of the leaves of some insectivorous Unlike other octocorals, however, a sea pen's polyps are specialized to specific functions: a single polyp develops into a rigid, erect stalk (the rachis) and loses its tentacles, forming a bulbous "root" or peduncle at its base. In Zoology, a polyp is one of two forms of individuals found in many species of Cnidarians The two are the polyp or hydroid and the medusa. Other polyps branch out from this central stalk, forming water intake structures (siphonozooids), feeding structures (autozooids) with nematocysts, and reproductive structures. A cnidocyte, cnidoblast or nematocyte, is a type of Venomous cell unique to the Phylum Cnidaria ( Corals The entire colony is fortified by calcium carbonate in the form of spicules and a central axial rod.
Using their root-like peduncles to anchor themselves in sandy or muddy substrate, the exposed portion of sea pens may rise up to 2 metres in some species, such as the tall sea pen (Funiculina quadrangularis). The metre or meter is a unit of Length. It is the basic unit of Length in the Metric system and in the International Sea pens are sometimes brightly coloured; the orange sea pen (Ptilosarcus gurneyi) is a notable example. Rarely found above depths of 10 metres, Sea pens prefer deeper waters where turbulence is less likely to uproot them. Some species may inhabit depths of 2,000 metres or more.
While generally sessile animals, sea pens are able to relocate and re-anchor themselves if need be. They position themselves favourably in the path of currents, ensuring a steady flow of plankton, the sea pens' chief source of food. Plankton consist of any drifting Organisms ( Animals Plants Archaea, or Bacteria) that inhabit the Pelagic zone of Their primary predators are nudibranchs and starfish, some of which feed exclusively on sea pens. A nudibranch (pronounced (BrE or (AmE is a member of one Suborder of soft-bodied shell-less marine Opisthobranch Gastropod Mollusks Starfish (also called sea stars) are any Echinoderms belonging to the class Asteroidea. When touched, sea pens emit a bright greenish light; this is known as bioluminescence. Bioluminescence' is the production and emission of Light by a living Organism as the result of a chemical reaction during which chemical energy is converted They may also force water out of themselves as a defensive act, deflating and retreating into their peduncle.
Like other anthozoans, sea pens reproduce by co-ordinating a release of sperm and eggs into the water column; this may occur seasonally or throughout the year. Corals are Marine organisms from the class Anthozoa and exist as small Sea anemone –like Polyps typically in colonies of many Fertilized eggs develop into larvae called planulae which drift freely for about a week before settling on the substrate. Mature sea pens provide shelter for other animals, such as juvenile fish. Fish are aquatic Vertebrate animals that are typically ectothermic (previously Cold-blooded) covered with scales, and equipped with two Analysis of rachis growth rings indicates sea pens may live for 100 years or more, if the rings are indeed annual in nature.
The sea pen fossil record is patchy and disputed by some; while the earliest accepted fossils are known from the Cambrian-aged Burgess Shale (Thaumaptilon), similar fossils from the late Proterozoic (Ediacaran) (ala Charnia) may represent the dawn of sea pens. FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. The Cambrian is a geologic period and system that began about Ma (million years ago at the end of the Proterozoic eon and ended about Ma with See also Burgess shale type fauna The Burgess Shale is famous for the exceptional preservation of the fossils found within it in which the soft parts are preserved Thaumaptilon is a fossil from the middle Cambrian bearing striking resemblance to a biota that had almost disappeared at the start of the Cambrian. The Proterozoic (ˌproʊtərəˈzoʊɪk is a geological eon representing a period before the first abundant complex life on Earth. The Ediacaran Period (ˌiːdiˈækərən named after the Ediacara Hills of South Australia) is the last geological period of the Neoproterozoic Charnia is the Genus name given to a Frond -like Precambrian lifeform with segmented ridges branching alternately to the right and left from a Precisely what the Proterozoic fossils are, however, is not decided.
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