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Bull Shark
The bull shark (''Carcharhinus leucas''), also known as the Zambezi shark (informally zambi) in Africa and Lake Nicaragua shark in Nicaragua, is a species of requiem shark commonly found worldwide in warm, shallow waters along coasts and in rivers. It is known for its aggressive nature, and presence mainly in warm, shallow brackish water, brackish and freshwater systems including estuaries and (usually) lower reach (geography), reaches of rivers. Their aggressive nature has led to ongoing shark-culling efforts near beaches to protect beachgoers, which is one of the causes of bull shark populations continuing to decrease. Bull sharks are listed as vulnerable on the IUCN Red List. Bull sharks are euryhaline and can thrive in both saltwater, salt and fresh water. They are known to travel far up rivers, and have been known to travel up the Mississippi River as far as Alton, Illinois, about from the ocean, but few freshwater interactions with humans have been recorded. Larger-sized ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Miocene
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene followed the Oligocene and preceded the Pliocene. As Earth went from the Oligocene through the Miocene and into the Pliocene, the climate slowly cooled towards a series of ice ages. The Miocene boundaries are not marked by distinct global events but by regionally defined transitions from the warmer Oligocene to the cooler Pliocene Epoch. During the Early Miocene, Afro-Arabia collided with Eurasia, severing the connection between the Mediterranean and Indian Oceans, and allowing the interchange of fauna between Eurasia and Africa, including the dispersal of proboscideans and Ape, hominoids into Eurasia. During the late Miocene, the conn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Littoral Zone
The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely flood, inundated), to coastal areas that are permanently underwater, submerged — known as the ''foreshore'' — and the terms are often used interchangeably. However, the geographical meaning of ''littoral zone'' extends well beyond the intertidal zone to include all neritic waters within the bounds of continental shelves. Etymology The word ''littoral'' may be used both as a noun and as an adjective. It derives from the Latin language, Latin noun ''litus, litoris'', meaning "shore". (The doubled ''t'' is a late-medieval innovation, and the word is sometimes seen in the more classical-looking spelling ''litoral''.) Description The term has no single definition. What is regarded as the full extent of the littoral zone, and the way the littora ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phylogeny
A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or Taxon, taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In other words, it is a branching diagram or a tree (graph theory), tree showing the evolutionary relationships among various biological species or other entities based upon similarities and differences in their physical or genetic characteristics. In evolutionary biology, all life on Earth is theoretically part of a single phylogenetic tree, indicating common ancestry. Phylogenetics is the study of phylogenetic trees. The main challenge is to find a phylogenetic tree representing optimal evolutionary ancestry between a set of species or taxa. computational phylogenetics, Computational phylogenetics (also phylogeny inference) focuses on the algorithms involved in finding optimal phylogenetic tree in the phylogenetic landscape. Phylogene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sandbar Shark
The sandbar shark (''Carcharhinus plumbeus''), also known as the brown shark or thickskin shark, is a species of requiem shark, and part of the family Carcharhinidae, native to the Atlantic Ocean and the Indo-Pacific. It is distinguishable by its very high first dorsal fin and interdorsal ridge. It is not to be confused with the similarly named sand tiger shark, or ''Carcharias taurus.'' Description and growth The sandbar shark is one of the largest coastal sharks in the world, and is closely related to the dusky shark, the bignose shark, and the bull shark. Its dorsal fin is triangular and very high, and it has very long pectoral fins. Sandbar sharks usually have heavy-set bodies and rounded snouts that are shorter than the average shark's snout. Its upper teeth have broadly uneven cusps with sharp edges. Its second dorsal fin and anal fin are close to the same height. Females can grow to 2–2.5 m (6.6–8.2 ft), males up to 1.8 m (5.9 ft). The maximum r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcharhinus
''Carcharhinus'' is the type genus of the family (biology), family Carcharhinidae, the requiem sharks. One of 12 genera in its family, it contains over half of the species therein. It contains 35 extant and eight extinct species to date, with likely more species yet to be described. Species Extant T Type species Fossil See also * List of prehistoric cartilaginous fish genera References Bibliography * * * * * * * {{Authority control Carcharhinus, Shark genera Extant Eocene first appearances Taxa named by Henri Marie Ducrotay de Blainville ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmoregulation
Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes ( salts in solution which in this case is represented by body fluid) to keep the body fluids from becoming too diluted or concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution, the more water tends to move into it. Pressure must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water. Although there may be hourly and daily variations in osmotic balance, an animal is generally in an osmotic steady state over the long term. Organisms in aquatic and terrestrial environments must maintain the right concentration of solutes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ganges River
The Ganges ( ; in India: Ganga, ; in Bangladesh: Padma, ). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international which goes through India, Bangladesh, Nepal and China." is a trans-boundary river of Asia which flows through India and Bangladesh. The river rises in the western Himalayas in the States and union territories of India, Indian state of Uttarakhand. It flows south and east through the Gangetic Plain, Gangetic plain of North India, receiving the right-bank tributary, the Yamuna, which also rises in the western Indian Himalayas, and several left-bank tributaries from Nepal that account for the bulk of its flow. In West Bengal state, India, a feeder canal taking off from its right bank diverts 50% of its flow southwards, artificially connecting it to the Hooghly River. The Ganges continues into Bangladesh, its name changing to the Padma River, Padma. It is then joined by the Jamuna River (Bangladesh), Jamuna, the lower str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zambezi
The Zambezi (also spelled Zambeze and Zambesi) is the fourth-longest river in Africa, the longest east-flowing river in Africa and the largest flowing into the Indian Ocean from Africa. Its drainage basin covers , slightly less than half of the Nile's. The river rises in Zambia and flows through eastern Angola, along the north-eastern border of Namibia and the northern border of Botswana, then along the border between Zambia and Zimbabwe to Mozambique, where it crosses the country to empty into the Indian Ocean. The Zambezi's most noted feature is Victoria Falls. Its other falls include the Chavuma Falls at the border between Zambia and Angola and Ngonye Falls near Sioma in western Zambia. The two main sources of hydroelectric power on the river are the Kariba Dam, which provides power to Zambia and Zimbabwe, and the Cahora Bassa Dam in Mozambique, which provides power to Mozambique and South Africa. Additionally, two smaller power stations are along the Zambezi River i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ganges Shark
The Ganges shark (''Glyphis gangeticus'') is a critically endangered species of requiem shark found in the Ganges River (Padma River) and the Brahmaputra River of India and Bangladesh. It is often confused with the more common bull shark (''Carcharhinus leucas''), which also inhabits the Ganges River and is sometimes incorrectly referred to as the Ganges shark. The genus is currently considered to contain three recent species; genetic evidence has shown that both the Borneo river shark (''G. fowlerae'') and Irrawaddy river shark (''G. siamensis'') should be regarded as synonyms of the Ganges shark, expanding the range of the species to Pakistan, Myanmar, Borneo, and Java. The species remains poorly known and very rare. Taxonomy Formerly the Borneo river shark (''Glyphis fowlerae'') and the Irrawaddy river shark (''Glyphis siamensis'') were considered to represent two other species in the genus ''Glyphis''. They have recently been reclassified as ''G. gangeticus'' based on genet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Costa Rica
Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime boundary, maritime border with Ecuador to the south of Cocos Island. It has a population of around five million in a land area of nearly . An estimated people live in the capital and largest city, San José, Costa Rica, San José, with around two million people in the surrounding metropolitan area. The sovereign state is a Presidential system, presidential republic. It has a long-standing and stable Constitution of Costa Rica, constitutional democracy and a highly educated workforce. The country spends roughly 6.9% of its budget (2016) on education, compared to a global average of 4.4%. Its economy, once heavily dependent on agriculture, has diversified to include sectors such as finance, corporate services for foreign companies, pharmaceut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Costa Rican Colón
The colón (plural: ''colones''; sign: ₡; code: CRC) is the currency of Costa Rica. It was named after Christopher Columbus, known as ''Cristóbal Colón'' in Spanish. A colón is divided into one hundred céntimos. Symbol The symbol for the colón is a capital letter "C" crossed by two diagonal strokes. The symbol is encoded at and may be typed on many English language Microsoft Windows keyboards using the keystrokes +. The colón sign is not to be confused with , or with the Ghanaian cedi, . Nonetheless, the commonly available cent symbol '¢' is frequently used locally to designate the colón in price markings and advertisements. History The colón was introduced in 1896, replacing the peso at par. The colón is divided into 100 centimos, although, between 1917 and 1919, coins were issued using the name centavo for the 1/100 subunit of the colón. Colones were issued by a variety of banks in the first half of the twentieth century, but since 1951 have been produced s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Shark
Freshwater sharks are sharks that live in freshwater environments. While the majority of sharks are solely marine, a small number of shark species have adapted to live in freshwater. The river sharks (of the genus ''Glyphis'') live in freshwater and coastal marine environments. The bull shark (''Carcharhinus leucas''), can swim between salt and fresh water, and are found in tropical rivers around the world. Some prehistoric sharks (in a broad sense), including hybodonts and xenacanths, are also thought to have inhabited freshwater environments. A small number of freshwater fish cyprinids and catfish (which are bony fish Osteichthyes ( ; ), also known as osteichthyans or commonly referred to as the bony fish, is a Biodiversity, diverse clade of vertebrate animals that have endoskeletons primarily composed of bone tissue. They can be contrasted with the Chondricht ... and thus quite unrelated to sharks) are also commonly called "freshwater sharks", "sharkminnows" or simply "sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
