|
Snakehead Fish
The snakeheads are members of the freshwater perciform fish family Channidae, native to parts of Africa and Asia. These elongated, predatory fish are distinguished by their long dorsal fins, large mouths, and shiny teeth. They breathe air with gills, which allows them to migrate short distances over land. They have suprabranchial organs, which are primitive forms of labyrinth organs, that develop when they grow older. The two extant genera are ''Channa'' in Asia and '' Parachanna'' in Africa, consisting of more than 50 species. They are valuable as a food source and have become notorious as an intentionally released invasive species. These fish have been kept as pets but as they get larger, people let them go into ponds, lakes, and rivers, making these fish invasive. Description The various species of snakeheads differ greatly in size; dwarf snakeheads, such as '' Channa orientalis'', do not surpass in length. Most other snakeheads reach between . Five species ('' C. argus'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Eos, Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Channa Barca
The Barca snakehead (''Channa barca'') is a rare species of snakehead. It is endemic to the upper Brahmaputra River basin in northeastern India and Bangladesh. Records from Nepal are of doubtful validity. Overall it has been assessed as data deficient by the IUCN, and in 2014 it was assessed as critically endangered in Bangladesh by the IUCN. In Assam, it is locally known as ''cheng garaka'' or ''garaka cheng''. This is a relatively large snakehead, reaching a total length of up to . The species is regarded as an excellent food fish, and it is also highly desired by aquarists, but its rarity, behavior and large size makes it unsuitable for most aquariums.SeriouslyFishChanna barca Retrieved 14 February 2019. Distribution, habitat and behavior The barca snakehead is only known from the upper Brahmaputra River basin the Assam and Nagaland in India, and Sylhet in Bangladesh. Records from Nepal are of doubtful validity. It mostly inhabits wetlands, often near the margins, but can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intertropical Convergence Zone
The Intertropical Convergence Zone (ITCZ , or ICZ), known by sailors as the doldrums or the calms because of its monotonous windless weather, is the area where the northeast and the southeast trade winds converge. It encircles Earth near the thermal equator though its specific position varies seasonally. When it lies near the geographic equator, it is called the near-equatorial trough. Where the ITCZ is drawn into and merges with a monsoon, monsoonal circulation, it is sometimes referred to as a ''monsoon trough'' (a usage that is more common in Australia and parts of Asia). Meteorology The ITCZ was originally identified from the 1920s to the 1940s as the ''Intertropical Front'' (''ITF''), but after the recognition in the 1940s and the 1950s of the significance of convergence zone, wind field convergence in tropics, tropical weather production, the term ''Intertropical Convergence Zone'' (''ITCZ'') was then applied. The ITCZ appears as a band of clouds, usually thunderstorms, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tortonian
The Tortonian is in the geologic time scale an age or stage of the late Miocene that spans the time between 11.608 ± 0.005 Ma and 7.246 ± 0.005 Ma (million years ago). It follows the Serravallian and is followed by the Messinian. The Tortonian roughly overlaps with the regional Pannonian Stage of the Paratethys timescale of Central Europe. It also overlaps the upper Astaracian, Vallesian and lower Turolian European land mammal ages, the upper Clarendonian and lower Hemphillian North American land mammal ages and the upper Chasicoan and lower Huayquerian South American land mammal ages. Definition The Tortonian was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1858. It was named after the Italian city of Tortona in the Piedmont region. The base of the Tortonian Stage is at the last common appearance of calcareous nanoplankton '' Discoaster kugleri'' and planktonic foram '' Globigerinoides subquadratus''. It is also associated with the short normal pol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burdigalian
The Burdigalian is, in the geologic timescale, an age (geology), age or stage (stratigraphy), stage in the early Miocene. It spans the time between 20.43 ± 0.05 annum, Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian (stage), Aquitanian, the Burdigalian was the first and longest warming period of the MioceneEdward Petuch, Ph.D. Florida Atlantic University, Department of Geosciences. and is succeeded by the Langhian. Stratigraphic definition The name Burdigalian comes from ''Burdigala'', the Latin name for the city of Bordeaux, France. The Burdigalian Stage was introduced in scientific literature by Charles Depéret in 1892. The base of the Burdigalian is at the first appearance of foram species ''Globigerinoides altiaperturus'' and the top of magnetic chronozone C6An. , an official GSSP for the Burdigalian had not yet been assigned. The top of the Burdigalian (the base of the Langhian) is defined by the first appearance of foram species ''Praeorbulina gl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Middle Eocene
The Eocene ( ) is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', ' Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isotope 13C in the atmosphere was exceptionally low in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eochanna Chorlakkiensis
''Eochanna chorlakkiensis'' is an extinct prehistoric snakehead. The fish lived in the Lutetian age of the Middle Eocene (41-48 million years ago) in the area of what is now the Kuldana Formation near Chorlakki, Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ....Roe, L. J. (1991):Phylogenetic and Ecological Significance of Channidae (Osteichthyes Teleostei) from the Early Eocene Kuldana Formation of Kohat, Pakistan. ''Contributions From The Museum Of Paleontology, The University Of Michigan, VOL. 28, NO. 5, PP. 93-10'' References Channidae Fossil taxa described in 1991 {{Anabantiformes-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ypresian
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the Lower Eocene (Early Eocene). Events The Ypresian Age begins during the throes of the Paleocene–Eocene Thermal Maximum (PETM). The Fur Formation in Denmark, the Messel shales in Germany, the Oise amber of France and Cambay amber of India are of this age. The Eocene Okanagan Highlands are an uplands subtropical to temperate series of lakes from the Ypresian. The Ypresian is additionally marked by another warming event called the Early Eocene Climatic Optimum (EECO). The EECO is the longest sustained warming event in the Cenozoic record, lasting about 2–3 million years between 53 and 50 Ma. The interval is characterized by low oxygen-18 isotopes, high levels of atmospheric pCO2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carp
The term carp (: carp) is a generic common name for numerous species of freshwater fish from the family (biology), family Cyprinidae, a very large clade of ray-finned fish mostly native to Eurasia. While carp are prized game fish, quarries and are valued (even pisciculture, commercially cultivated) as both food fish, food and ornamental fish in many parts of the Old World, they are considered trash fish and invasive species, invasive pest (organism), pests in many parts of Africa, Australia and most of the United States. Biology The cypriniformes (family Cyprinidae) are traditionally grouped with the Characiformes, Siluriformes, and Gymnotiformes to create the superorder Ostariophysi, since these groups share some common features. These features include being found predominantly in fresh water and possessing Weberian ossicles, an anatomical structure derived from the first five anterior-most vertebrae, and their corresponding ribs and neural crests. The third anterior-most pair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mollusk
Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The number of additional fossil species is estimated between 60,000 and 100,000, and the proportion of undescribed species is very high. Many taxa remain poorly studied. Molluscs are the largest marine phylum, comprising about 23% of all the named marine organisms. They are highly diverse, not just in size and anatomical structure, but also in behaviour and habitat, as numerous groups are freshwater and even terrestrial species. The phylum is typically divided into 7 or 8 taxonomic classes, of which two are entirely extinct. Cephalopod molluscs, such as squid, cuttlefish, and octopuses, are among the most neurologically advanced of all invertebrates—and either the giant squid or the colossal squid is the largest known extant i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquatic Insect
Aquatic insects or water insects live some portion of their life cycle in the water. They feed in the same ways as other insects. Some ''diving'' insects, such as predatory diving beetles, can hunt for food underwater where land-living insects cannot compete. Breathing One problem that aquatic insects must overcome is how to get oxygen while they are under water. Almost all animals require a source of oxygen to live. Insects draw air into their bodies through spiracles, holes found along the sides of the abdomen. These spiracles are connected to tracheal tubes where oxygen can be absorbed. All aquatic insects have become adapted to their environment with the specialization of these structures ;Aquatic adaptations # Simple diffusion over a relatively thin integument # Temporary use of an air bubble # Extraction of oxygen from water using a plastron or blood gill # Storage of oxygen in hemoglobin and hemocyanin molecules in hemolymph # Taking oxygen from surface via brea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales. Marine plankton include bacteria, archaea, algae, protozoa, microscopic fungi, and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. fresh water, Freshwater plankton are similar to marine plankton, but are found in lakes and rivers. Mostly, plankton just drift where currents take them, though some, like jellyfish, swim slowly but not fast enough to generally overcome the influence of currents. Although plankton are usually thought of as inhabiting water, there are also airborne versions that live part of their lives drifting in the at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
