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Daphnia Barbata
''Daphnia barbata'' is a species of water flea within the family Daphniidae. It occurs in several places within Africa including Lake Chad in northwest Africa and in the Makgadikgadi Pan in Botswana. See also * Cryptobiosis Cryptobiosis or anabiosis is a metabolic state of life entered by an organism in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency. In the cryptobiotic state, all measurable metabolic processes stop ... References Cladocera Freshwater crustaceans of Africa Crustaceans described in 1898 {{Branchiopoda-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Weltner
Wilhelm may refer to: People and fictional characters * William Charles John Pitcher, costume designer known professionally as "Wilhelm" * Wilhelm (name), a list of people and fictional characters with the given name or surname Other uses * Mount Wilhelm, the highest mountain in Papua New Guinea * Wilhelm Archipelago, Antarctica * Wilhelm (crater), a lunar crater See also * Wilhelm scream The Wilhelm scream is a stock sound effect that has been used in a number of films and TV series, beginning in 1951 with the film ''Distant Drums''. The scream is usually used when someone is shot, falls from a great height, or is thrown from a ..., a stock sound effect * SS ''Kaiser Wilhelm II'', or USS ''Agamemnon'', a German steam ship * Wilhelmus, the Dutch national anthem {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Water Flea
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, even if several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. Description They are mostly long, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daphniidae
Daphniidae is a family of water fleas in the order Anomopoda. Description Members of the family Daphniidae differ from other, similar diplostracans, such as the Macrotrichidae and Moinidae, in that the antennae of females are short and immobile. Ecology The feeding mechanism of the members of the family Daphniidae differs from that of the Macrotrichidae in allowing the animals to engage in filter feeding, rather than having to scrape food from a surface. They have evolved to fill a number of different ecological niches. '' Scapholeberis'' and '' Megafenestra'' contain species adapted to living around the surface film; '' Simocephalus'' species cling to objects while filter feeding; others have developed a pelagic lifestyle. Taxonomy The family Daphniidae contains 121 species in five genera: *'' Ceriodaphnia'' Dana, 1853 *''Daphnia'' O. F. Müller, 1785 *'' Megafenestra'' Dumont & Pensaert, 1983 *'' Scapholeberis'' Schoedler, 1858 *'' Simocephalus'' Schoedler, 1858 The memb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Africa
Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area and 20% of its land area.Sayre, April Pulley (1999), ''Africa'', Twenty-First Century Books. . With billion people as of , it accounts for about of the world's human population. Africa's population is the youngest amongst all the continents; the median age in 2012 was 19.7, when the worldwide median age was 30.4. Despite a wide range of natural resources, Africa is the least wealthy continent per capita and second-least wealthy by total wealth, behind Oceania. Scholars have attributed this to different factors including geography, climate, tribalism, Scramble for Africa, colonialism, the Cold War, neocolonialism, lack of democracy, and corruption. Despite this low concentration of wealth, recent economic expansion and the large and young ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Chad
Lake Chad (french: Lac Tchad) is a historically large, shallow, endorheic lake in Central Africa, which has varied in size over the centuries. According to the ''Global Resource Information Database'' of the United Nations Environment Programme, it shrank by as much as 95% from about 1963 to 1998. The lowest area was in 1986, at , but "the 2007 (satellite) image shows significant improvement over previous years." Lake Chad is economically important, providing water to more than 30 million people living in the four countries surrounding it (Chad, Cameroon, Niger, and Nigeria) on the central part of the Sahel. It is the largest lake in the Chad Basin. Geography and hydrology The freshwater lake is located in the Sahelian zone of West-central Africa. It is located in the interior basin which used to be occupied by a much larger ancient sea sometimes called Mega Chad. The lake is historically ranked as one of the largest lakes in Africa. Its surface area varies by season as well a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Makgadikgadi Pan
The Makgadikgadi Pan ( Tswana pronunciation ), a salt pan situated in the middle of the dry savanna of north-eastern Botswana Botswana (, ), officially the Republic of Botswana ( tn, Lefatshe la Botswana, label= Setswana, ), is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory being the Kal ..., is one of the largest Dry lake, salt flats in the world. The pan is all that remains of the formerly enormous Lake Makgadikgadi, which once covered an area larger than Switzerland, but dried up tens of thousands of years ago. Recent studies of human mitochondrial DNA suggest that modern ''Homo sapiens'' first began to evolve in this region some 200,000 years ago, when it was a vast, exceptionally fertile area of lakes, rivers, marshes, woodlands and grasslands especially favorable for habitation by evolving hominins and other mammals. Location and description Lying southeast of the Okavango Delta and s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botswana
Botswana (, ), officially the Republic of Botswana ( tn, Lefatshe la Botswana, label= Setswana, ), is a landlocked country in Southern Africa. Botswana is topographically flat, with approximately 70 percent of its territory being the Kalahari Desert. It is bordered by South Africa to the south and southeast, Namibia to the west and north, and Zimbabwe to the northeast. It is connected to Zambia across the short Zambezi River border by the Kazungula Bridge. A country of slightly over 2.3 million people, Botswana is one of the most sparsely populated countries in the world. About 11.6 percent of the population lives in the capital and largest city, Gaborone. Formerly one of the world's poorest countries—with a GDP per capita of about US$70 per year in the late 1960s—it has since transformed itself into an upper-middle-income country, with one of the world's fastest-growing economies. Modern-day humans first inhabited the country over 200,000 years ago. The Tswa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptobiosis
Cryptobiosis or anabiosis is a metabolic state of life entered by an organism in response to adverse environmental conditions such as desiccation, freezing, and oxygen deficiency. In the cryptobiotic state, all measurable metabolic processes stop, preventing reproduction, development, and repair. When environmental conditions return to being hospitable, the organism will return to its metabolic state of life as it was prior to the cryptobiosis. Forms Anhydrobiosis Anhydrobiosis is the most studied form of cryptobiosis and occurs in situations of extreme desiccation. The term ''anhydrobiosis'' derives from the Greek for "life without water" and is most commonly used for the desiccation tolerance observed in certain invertebrate animals such as bdelloid rotifers, tardigrades, brine shrimp, nematodes, and at least one insect, a species of chironomid ('' Polypedilum vanderplanki''). However, other life forms exhibit desiccation tolerance. These include the resurrection ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cladocera
The Diplostraca or Cladocera, commonly known as water fleas, are a superorder of small crustaceans that feed on microscopic chunks of organic matter (excluding some predatory forms). Over 1000 species have been recognised so far, with many more undescribed. The oldest fossils of diplostracans date to the Jurassic, though their modern morphology suggests that they originated substantially earlier, during the Paleozoic. Some have also adapted to a life in the ocean, the only members of Branchiopoda to do so, even if several anostracans live in hypersaline lakes. Most are long, with a down-turned head with a single median compound eye, and a carapace covering the apparently unsegmented thorax and abdomen. Most species show cyclical parthenogenesis, where asexual reproduction is occasionally supplemented by sexual reproduction, which produces resting eggs that allow the species to survive harsh conditions and disperse to distant habitats. Description They are mostly long, wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Freshwater Crustaceans Of Africa
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include non- salty mineral-rich waters such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/ 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, subterranean rivers and lakes. Fresh water is the water resource that is of the most and immediate use to humans. Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of higher plants and most insects, amphibians, reptiles, mammals and birds need fresh water to survive. Fresh water is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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