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Warnowia
''Warnowia'' is a genus of athecate dinoflagellates, characterized by having a very sophisticated photoreceptor organelle called the ocelloid. This genus is dispersed worldwide but is scarce and difficult to find and nearly impossible to culture. As a result, the history and taxonomy of this genus are confusing at best, and many basic characteristics like its life cycle are still unknown. Still, ''Warnowia'' has drawn scientific interest as a unicellular organism with a fascinatingly complex photoreceptor system. History of knowledge The first description of the genus was in 1895 by Schütt, who called it '' Pouchetia'', and designated the type species ''Pouchetia fusus''. In 1921, Kofoid & Swezy described many new species of ''Pouchetia'' in a collection of notes on free-living athecate dinoflagellates. Although today it is commonly believed that many of the species described by Kofoid & Swezy are conspecific, their thorough and numerable descriptions of marine protists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nematodinium
''Nematodinium'' is a genus of athecate marine dinoflagellates. Roughly ovoid in shape, their defining characteristic is the presence of nematocysts, from which their name is derived. They are part of the Warnowiacaea family that are famous for the ocelloid, an eye-like organelle that responds to light. Etymology The name of the genus comes from Charles A. Kofoid and Olive Swezy (1921) to describe the characteristic feature of the genus: the presence of nematocysts, small explosive extrusome organelles that are similar to mucocysts in size and shape. Type species The type species of ''Nematodinium'' is ''Nematodinium partitum.'' Kofoid and Swezy first described the genus ''Nematodinium'' in 1921. They described two novel species of ''Nematodinium'': ''N. partitum'', ''N. torpedo'', as well as ''N. armatum'' which had first been observed by Dogiel in 1906. Habitat ''Nematodinium'' are very rare and fragile, making them challenging both to culture and to study as they will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythropsidinium
''Erythropsidinium'' (formerly ''Erythropsis'') is a genus of dinoflagellates (a type of unicellular eukaryote) of the family Warnowiaceae. Characteristics ''Erythropsidinium'' cells are a relatively large by dinoflagellate standards (50-120μm in longest dimension) and possess two flagella and two unusual organelles, the ocelloid and the piston. The ocelloid is light-responsive structure organized similarly to a multicellular organism's eye, considered a synapomorphic character for the Warnowiaceae; cells typically contain one ocelloid but occasional examples have been reported of cells containing two, without other indications of ongoing cell division. The piston is a long contractile structure protruding from the cell body, which is highly variable in length and morphology, and may contain prominent nodules along its length. As with the ocelloid, most cells possess a single piston, but in some cases specimens have been observed with two pistons on the same cell. The piston ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocelloid
An ocelloid is a subcellular structure found in the family (biology), family Warnowiaceae (warnowiids), which are members of a group of unicellular organisms known as dinoflagellates. The ocelloid is analogous in structure and function to the eyes of multicellular organisms, which focus, process and detect light. The ocelloid is much more complex than the eyespot apparatus, eyespot, a light-sensitive structure also found in unicellular organisms, and is in fact one of the most complex known subcellular structures. It has been described as a striking example of convergent evolution. History The ocelloid was originally described in 1884. Early descriptions were met with skepticism and hypothesized to represent the eye of a multicellular organism coincidentally engulfed by a single-celled organism. The possibility that it had an evolutionary relationship to plastids had been considered at least since the 1970s, although until the 2010s direct evidence was scarce. Structure Ocell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinoflagellate
The Dinoflagellates (), also called Dinophytes, are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered protists. Dinoflagellates are mostly marine plankton, but they are also common in freshwater habitats. Their populations vary with sea surface temperature, salinity, and depth. Many dinoflagellates are photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey ( phagotrophy and myzocytosis). In terms of number of species, dinoflagellates are one of the largest groups of marine eukaryotes, although substantially smaller than diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, '' Oodinium'' and '' Pfiesteria''). Some dinoflagellates produce resting stages, called dinoflagellate cys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protist
A protist ( ) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus. Protists do not form a natural group, or clade, but are a paraphyletic grouping of all descendants of the last eukaryotic common ancestor excluding land plants, animals, and fungi. Protists were historically regarded as a separate taxonomic kingdom known as Protista or Protoctista. With the advent of phylogenetic analysis and electron microscopy studies, the use of Protista as a formal taxon was gradually abandoned. In modern classifications, protists are spread across several eukaryotic clades called supergroups, such as Archaeplastida ( photoautotrophs that includes land plants), SAR, Obazoa (which includes fungi and animals), Amoebozoa and " Excavata". Protists represent an extremely large genetic and ecological diversity in all environments, including extreme habitats. Their diversity, larger than for all other eukaryotes, has only been discovered in rece ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dinoflagellate
The Dinoflagellates (), also called Dinophytes, are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered protists. Dinoflagellates are mostly marine plankton, but they are also common in freshwater habitats. Their populations vary with sea surface temperature, salinity, and depth. Many dinoflagellates are photosynthetic, but a large fraction of these are in fact mixotrophic, combining photosynthesis with ingestion of prey ( phagotrophy and myzocytosis). In terms of number of species, dinoflagellates are one of the largest groups of marine eukaryotes, although substantially smaller than diatoms. Some species are endosymbionts of marine animals and play an important part in the biology of coral reefs. Other dinoflagellates are unpigmented predators on other protozoa, and a few forms are parasitic (for example, '' Oodinium'' and '' Pfiesteria''). Some dinoflagellates produce resting stages, called dinoflagellate cys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Caribbean Sea, and to the south and west by the Pacific Ocean. The region includes Middle America (Americas), Middle America (comprising the Caribbean, Central America, and Mexico) and Northern America. North America covers an area of about , representing approximately 16.5% of Earth's land area and 4.8% of its total surface area. It is the third-largest continent by size after Asia and Africa, and the list of continents and continental subregions by population, fourth-largest continent by population after Asia, Africa, and Europe. , North America's population was estimated as over 592 million people in list of sovereign states and dependent territories in North America, 23 independent states, or about 7.5% of the world's popula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mediterranean Sea
The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Europe, on the south by North Africa, and on the west almost by the Morocco–Spain border. The Mediterranean Sea covers an area of about , representing 0.7% of the global ocean surface, but its connection to the Atlantic via the Strait of Gibraltar—the narrow strait that connects the Atlantic Ocean to the Mediterranean Sea and separates the Iberian Peninsula in Europe from Morocco in Africa—is only wide. Geological evidence indicates that around 5.9 million years ago, the Mediterranean was cut off from the Atlantic and was partly or completely desiccation, desiccated over a period of some 600,000 years during the Messinian salinity crisis before being refilled by the Zanclean flood about 5.3 million years ago. The sea was an important ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nordic Seas
The Nordic Seas are located north of Iceland and south of Svalbard. They have also been defined as the region located north of the Greenland-Scotland Ridge and south of the Fram Strait-Spitsbergen-Norway intersection. Known to connect the North Pacific and the North Atlantic waters, this region is also known as having some of the densest waters, creating the densest region found in the North Atlantic Deep Water. The deepest waters of the Arctic Ocean are connected to the worlds other oceans through Nordic Seas and Fram Strait. There are three seas within the Nordic Sea: Greenland Sea, Norwegian Sea, and Iceland Sea. The Nordic Seas only make up about 0.75% of the world's oceans. This region is known as having diverse features in such a small topographic area, such as the mid oceanic ridge systems. Some locations have shallow shelves, while others have deep slopes and basins. This region, because of the atmosphere-ocean transfer of energy and gases, has varying seasonal clim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vancouver Island
Vancouver Island is an island in the northeastern Pacific Ocean and part of the Canadian province of British Columbia. The island is in length, in width at its widest point, and in total area, while are of land. The island is the largest by area and the most populous along the west coasts of the Americas. The southern part of Vancouver Island and some of the nearby Gulf Islands are the only parts of British Columbia or Western Canada to lie south of the 49th parallel. The southeast part of the island has one of the warmest climates in Canada, and since the mid-1990s has been mild enough in a few areas to grow Mediterranean crops such as olives and lemons. The population of Vancouver Island was 864,864 as of 2021. Nearly half of that population (~400,000) live in the metropolitan area of Greater Victoria on the southern tip of the island, which includes Victoria, the capital of British Columbia. Other notable cities and towns on Vancouver Island include Nanaimo, Campb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
English Channel
The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busiest Sea lane, shipping area in the world. It is about long and varies in width from at its widest to at its narrowest in the Strait of Dover."English Channel". ''The Columbia Encyclopedia'', 2004. It is the smallest of the shallow seas around the continental shelf of Europe, covering an area of some . The Channel aided the United Kingdom in becoming a naval superpower, serving as a natural defence against invasions, such as in the Napoleonic Wars and in the World War II, Second World War. The northern, English coast of the Channel is more populous than the southern, French coast. The major languages spoken in this region are English language, English and French language, French. Names Roman historiography, Roman sources as (or , ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massachusetts
Massachusetts ( ; ), officially the Commonwealth of Massachusetts, is a U.S. state, state in the New England region of the Northeastern United States. It borders the Atlantic Ocean and the Gulf of Maine to its east, Connecticut and Rhode Island to its south, New Hampshire and Vermont to its north, and New York (state), New York to its west. Massachusetts is the List of U.S. states and territories by area, sixth-smallest state by land area. With a 2024 U.S. Census Bureau-estimated population of 7,136,171, its highest estimated count ever, Massachusetts is the most populous state in New England, the List of U.S. states and territories by population, 16th-most-populous in the United States, and the List of states and territories of the United States by population density, third-most densely populated U.S. state, after New Jersey and Rhode Island. Massachusetts was a site of early British colonization of the Americas, English colonization. The Plymouth Colony was founded in 16 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
