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Tilapia Guinasana
The Otjikoto tilapia (''Tilapia guinasana'') is a critically endangered species of cichlid fish endemic to Namibia where it was originally only found in Lake Guinas. This very small sinkhole lake contains quite clear water that generally ranges between depending on season,van Jaarsveld, E. (December 2013)Otjikoto Tilapia. South African National Biodiversity Institute. Retrieved 18 April 2017. and the Otjikoto tilapia has been seen down to depths of . Despite deriving its common name from the nearby Lake Otjikoto, it in not native to that lake, rather being an introduced species. It is rare in the aquarium tradeSeriouslyFishTilapia guinasana.Retrieved 18 April 2017. and also kept in garden ponds in southern Africa. It is shoaling, but when breeding the pairs separate out, moving to the lake's vertical cliff edges where narrow ledges are used for breeding. The eggs and young are aggressively guarded by the parents. The Otjikoto tilapia mostly feeds on algae, including diatoms, b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethelwynn Trewavas
Ethelwynn Trewavas (5 November 1900 – 16 August 1993) was an ichthyologist at the British Museum of Natural History. She was known for her work on the families Cichlidae and Sciaenidae. She worked with Charles Tate Regan, another ichthyologist and taxonomist. Academic studies and career She received her bachelor's degree and Board of Education Certificate in Teaching in 1921 from Reading University, and then worked as a teacher before being employed by the King's College of Household and Social Science as a part-time demonstrator, spending most of her time on research. She was taught by Dr. Nellie B. Eales when associated with the Freshwater Biological Association. She met Charles Regan and was employed by him as his assistant until hired by the British Museum (Natural History) as Assistant Keeper in 1935. She was appointed Deputy Keeper of Zoology in 1958, and retired in 1961. She served as the senior scientist in the Fish Section of the British Museum (Natural Hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Measurement
Fish measurement is the measuring of individual fish and various parts of their anatomies, for data used in many areas of ichthyology, including taxonomy and fishery biology. Overall length Standard length (SL) is the length of a fish measured from the tip of the snout to the posterior end of the last vertebra or to the posterior end of the midlateral portion of the hypural plate. This measurement excludes the length of the caudal (tail) fin. Total length (TL) is the length of a fish measured from the tip of the snout to the tip of the longer lobe of the caudal fin, usually measured with the lobes compressed along the midline. It is a straight-line measure, not measured over the curve of the body. Standard length measurements are used with Teleostei (most bony fish), while total length measurements are used with Myxini (hagfish), Petromyzontiformes ( lampreys) and usually Elasmobranchii (shark Sharks are a group of elasmobranch cartilaginous fish characterized by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endemic Fauna Of Namibia
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsewhere. For example, the Cape sugarbird is found exclusively in southwestern South Africa and is therefore said to be ''endemic'' to that particular part of the world. An endemic species can also be referred to as an ''endemism'' or, in scientific literature, as an ''endemite''. Similarly, many species found in the Western ghats of India are examples of endemism. Endemism is an important concept in conservation biology for measuring biodiversity in a particular place and evaluating the risk of extinction for species. Endemism is also of interest in evolutionary biology, because it provides clues about how changes in the environment cause species to undergo range shifts (potentially expanding their range into a larger area or becoming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Fish Of Namibia
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salt (chemistry), salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mineral water, mineral-rich waters, such as chalybeate springs. Fresh water may encompass frozen water, frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ice pellets, sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranea (geography), subterranean subterranean river, rivers and underground lake, lakes. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of vascular plants and most insects, amphibians, reptiles, mammals and birds need fresh water to sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cichlid Fish Of Africa
This is a list of African cichlid species that are commonly kept by aquarists. Another African cichlid is a Cyphotilapia frontosa, Frontosa (Cyphotilapia frontosa) which is commonly found in Lake Tanganyika. It grows to about 10-14 inches has minimal aggression and is stripy. See also *List of South American cichlids *Aquarium References {{DEFAULTSORT:Cichlid fish of Africa Cichlid fish of Africa, ' Lists of fishes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tilapia
Tilapia ( ) is the common name for nearly a hundred species of cichlid fish from the coelotilapine, coptodonine, heterotilapine, oreochromine, pelmatolapiine, and tilapiine tribes (formerly all were "Tilapiini"), with the economically most important species placed in the Coptodonini and Oreochromini. Tilapia are mainly freshwater fish native to Africa and the Middle East, inhabiting shallow streams, ponds, rivers, and lakes, and less commonly found living in brackish water. Historically, they have been of major importance in artisanal fishing in Africa, and they are of increasing importance in aquaculture and aquaponics. Tilapia can become a problematic invasive species in new warm-water habitats such as Australia, whether deliberately or accidentally introduced, but generally not in temperate climates due to their inability to survive in cold water. Traditionally a popular and affordable food in the Philippines with a mild taste, tilapia has been the fourth-most consume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interbreed
In biology, a hybrid is the offspring resulting from combining the qualities of two organisms of different variety (botany), varieties, subspecies, species or genus, genera through sexual reproduction. Generally, it means that each cell has genetic material from two different organisms, whereas an individual where some cells are derived from a different organism is called a chimera (genetics), chimera. Hybrids are not always intermediates between their parents such as in blending inheritance (a now discredited theory in modern genetics by particulate inheritance), but can show Heterosis, hybrid vigor, sometimes growing larger or taller than either parent. The concept of a hybrid is interpreted differently in animal and plant breeding, where there is interest in the individual parentage. In genetics, attention is focused on the numbers of chromosomes. In taxonomy, a key question is how closely related the parent species are. Species are reproductive isolation, reproductively isola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Banded Tilapia
''Tilapia sparrmanii'', the banded tilapia, or vlei kurper, is a widespread and adaptable cichlid fish that is found in warmer freshwater habitats of southern Africa. They prefer water with ample plant cover, and occur naturally as far north as DR Congo and Tanzania. They have been Introduced species, introduced locally in the northern hemisphere. Younger banded tilapia feed on crustaceans and insect larvae, while the adults feed on terrestrial and aquatic plants and other debris. They undertake local migrations and may Shoaling and schooling, shoal before and during spawning time. They guard their own eggs, and although they may move eggs or fry in the mouth, they are not known to be actual mouthbrooders like several other tilapia species. This species can reach a length of fish measurement, TL and is an important foodfish. The identity of the person honoured in the Specific name (zoology), specific name is uncertain but it is probably the Swedish people, Swedish naturalist And ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nguni Cattle
The Nguni is a cattle breed indigenous to Southern Africa. A hybrid of different Indian and later European cattle breeds, they were introduced by pastoralist tribes ancestral to modern Nguni people to Southern Africa during their migration from the North of the continent. Nguni cattle are dairy and beef cattle. The cattle breed is medium-sized and adapted to grazing on the highveld. Characteristics Nguni cattle are known for their fertility and resistance to diseases, being the favourite and most beloved breed amongst the local Bantu-speaking people of southern Africa (South Africa, Eswatini, Namibia, Zimbabwe, Botswana, and Angola). They are characterised by their multicoloured skin, which can present many different patterns, but their noses are always black-tipped. They are a principal form of Sanga cattle, which originated as hybrids of Zebu and humpless cattle in East Africa. DNA analyses have confirmed that they are a combination of '' Bos indicus'' and ''Bos taurus'', th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetics
Genetics is the study of genes, genetic variation, and heredity in organisms.Hartl D, Jones E (2005) It is an important branch in biology because heredity is vital to organisms' evolution. Gregor Mendel, a Moravian Augustinians, Augustinian friar working in the 19th century in Brno, was the first to study genetics scientifically. Mendel studied "trait inheritance", patterns in the way traits are handed down from parents to offspring over time. He observed that organisms (pea plants) inherit traits by way of discrete "units of inheritance". This term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. Phenotypic trait, Trait inheritance and Molecular genetics, molecular inheritance mechanisms of genes are still primary principles of genetics in the 21st century, but modern genetics has expanded to study the function and behavior of genes. Gene structure and function, variation, and distribution are studied within the context of the Cell (bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, dioecious species, which consist of most animals and some plants. Differences may include secondary sex characteristics, size, weight, color, markings, or behavioral or cognitive traits. Male-male reproductive competition has evolved a diverse array of sexually dimorphic traits. Aggressive utility traits such as "battle" teeth and blunt heads reinforced as battering rams are used as weapons in aggressive interactions between rivals. Passive displays such as ornamental feathering or song-calling have also evolved mainly through sexual selection. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', when both biological sexes are phenotype, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
