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Great Gerbil
The great gerbil (''Rhombomys opimus'') is a large rodent found throughout much of Central Asia. Description The largest of the gerbils, great gerbils have a head and body length of . Their skulls are distinctive by having two grooves in each incisor. They have large front claws used for burrowing. Distribution and habitat Great gerbils are found in arid habitats, predominantly in sandy or clay deserts. They are found in Turkmenistan, Kazakhstan, Mongolia, China, Pakistan, Afghanistan, and Iran. Predators The great gerbil is preyed on by foxes, owls, kites, wildcats, vultures, and cobras. Ecology and behavior Great gerbils live in family groups and occupy one burrow per family. Their burrows can be fairly extensive with separate chambers for nests and food storage. Great gerbils spend considerably more time in the burrows during winter, but do not hibernate. They are predominantly diurnal. Food consists mostly of vegetable matter. The animals are often colonial. Longevit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johann Andreas Wagner
Johann Andreas Wagner (21 March 1797 – 17 December 1861) was a German palaeontologist, zoologist and archaeologist who wrote several important works on palaeontology. Career Wagner was a professor at the University of Munich, and curator of the Zoologische Staatssammlung (State Zoology Collection). He was the author of ''Die Geographische Verbreitung der Säugethiere Dargestellt'' (1844–46). Wagner was a Christian creationist. Pikermi In his travels to the fossil beds of Pikermi, Wagner discovered and described fossil remains of mastodon, ''Dinotherium ''Deinotherium'' was a large elephant-like proboscidean that appeared in the Middle Miocene and survived until the Early Pleistocene. Although superficially resembling modern elephants, they had notably more flexible necks, limbs adapted to a ...'', '' Hipparion'', two species of giraffe, antelope and others. His collaboration with Johannes Roth on these fossils became a major textbook in palaeontology, known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wildcats
The wildcat is a species complex comprising two small wild cat species: the European wildcat (''Felis silvestris'') and the African wildcat (''F. lybica''). The European wildcat inhabits forests in Europe, Anatolia and the Caucasus, while the African wildcat inhabits semi-arid landscapes and steppes in Africa, the Arabian Peninsula, Central Asia, into western India and western China. The wildcat species differ in fur pattern, tail, and size: the European wildcat has long fur and a bushy tail with a rounded tip; the smaller African wildcat is more faintly striped, has short sandy-gray fur and a tapering tail; the Asiatic wildcat (''F. lybica ornata'') is spotted. The wildcat and the other members of the cat family had a common ancestor about 10–15 million years ago. The European wildcat evolved during the Cromerian Stage about 866,000 to 478,000 years ago; its direct ancestor was ''Felis lunensis''. The ''silvestris'' and ''lybica'' lineages probably diverged about 173,000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical ero ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pest (organism)
A pest is any animal or plant harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environment for their own purposes and are intolerant of other creatures occupying the same space when their activities impact adversely on human objectives. Thus, an elephant is unobjectionable in its natural habitat but a pest when it tramples crops. Some animals are disliked because they bite or sting; snakes, wasps, ants, bed bugs, fleas and ticks belong in this category. Others enter the home; these include houseflies, which land on and contaminate food, beetles, which tunnel into the woodwork, and other animals that scuttle about on the floor at night, like cockroaches, which are often associated with unsanitary conditions. Agricultural and horticultural crops are attacked by a wide variety of pests, the most important being insects, mit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agriculture
Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to live in cities. The history of agriculture began thousands of years ago. After gathering wild grains beginning at least 105,000 years ago, nascent farmers began to plant them around 11,500 years ago. Sheep, goats, pigs and cattle were domesticated over 10,000 years ago. Plants were independently cultivated in at least 11 regions of the world. Industrial agriculture based on large-scale monoculture in the twentieth century came to dominate agricultural output, though about 2 billion people still depended on subsistence agriculture. The major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials (such as rubber). Food classes include cereals (grains), vegetables, fruits, cooking oils, meat, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cutaneous Leishmaniasis
Cutaneous leishmaniasis is the most common form of leishmaniasis affecting humans. It is a skin infection caused by a single-celled parasite that is transmitted by the bite of a phlebotomine sand fly. There are about thirty species of '' Leishmania'' that may cause cutaneous leishmaniasis. This disease is considered to be a zoonosis (an infectious disease that is naturally transmissible from animals to humans), with the exception of ''Leishmania tropica'' — which is often an anthroponotic disease (an infectious disease that is naturally transmissible from humans to vertebrate animals). Signs and symptoms Post kala-azar dermal leishmaniasis Post-kala-azar dermal leishmaniasis (PKDL) is a recurrence of kala-azar that may appear on the skin of affected individuals months and up to 20 years after being partially treated, untreated or even in those considered adequately treated. In Sudan, they can be demonstrated in up to 60% of treated cases. They manifest as hypopigmented ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zoonosis
A zoonosis (; plural zoonoses) or zoonotic disease is an infectious disease of humans caused by a pathogen (an infectious agent, such as a bacterium, virus, parasite or prion) that has jumped from a non-human (usually a vertebrate) to a human. Typically, the first infected human transmits the infectious agent to at least one other human, who, in turn, infects others. Major modern diseases such as Ebola virus disease and salmonellosis are zoonoses. HIV was a zoonotic disease transmitted to humans in the early part of the 20th century, though it has now evolved into a separate human-only disease. Most strains of influenza that infect humans are human diseases, although many strains of bird flu and swine flu are zoonoses; these viruses occasionally recombine with human strains of the flu and can cause pandemics such as the 1918 Spanish flu or the 2009 swine flu. '' Taenia solium'' infection is one of the neglected tropical diseases with public health and veterinary concern i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leishmania Major
''Leishmania major'' is a species of parasite found in the genus '' Leishmania'', and is associated with the disease zoonotic cutaneous leishmaniasis (also known as Aleppo boil, Baghdad boil, Bay sore, Biskra button, Chiclero ulcer, Delhi boil, Kandahar sore, Lahore sore, Oriental sore, Pian bois, and Uta). ''L. major'' is an intracellular pathogen which infects the macrophages and dendritic cells of the immune system. Though ''Leishmania'' species are found on every continent aside from Antarctica, ''Leishmania major'' is found only in the Eastern Hemisphere, specifically in Northern Africa, the Middle East, Northwestern China, and Northwestern India. Biology Life cycle As a trypanosomatid, ''L. major'' begins its lifecycle in amastigote form in the midgut of the main vector, female sand flies ('' Phlebotomus spp.''). Once in the gut of the sand fly, the parasites change from aflagelated amastigotes into flagellated promastigotes for 1–2 weeks until they are fully ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bubonic Plague
Bubonic plague is one of three types of plague caused by the plague bacterium ('' Yersinia pestis''). One to seven days after exposure to the bacteria, flu-like symptoms develop. These symptoms include fever, headaches, and vomiting, as well as swollen and painful lymph nodes occurring in the area closest to where the bacteria entered the skin. Acral necrosis, the dark discoloration of skin, is another symptom. Occasionally, swollen lymph nodes, known as " buboes," may break open. The three types of plague are the result of the route of infection: bubonic plague, septicemic plague, and pneumonic plague. Bubonic plague is mainly spread by infected fleas from small animals. It may also result from exposure to the body fluids from a dead plague-infected animal. Mammals such as rabbits, hares, and some cat species are susceptible to bubonic plague, and typically die upon contraction. In the bubonic form of plague, the bacteria enter through the skin through a flea bite a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yersinia Pestis
''Yersinia pestis'' (''Y. pestis''; formerly '' Pasteurella pestis'') is a gram-negative, non-motile, coccobacillus bacterium without spores that is related to both ''Yersinia pseudotuberculosis'' and ''Yersinia enterocolitica''. It is a facultative anaerobic organism that can infect humans via the Oriental rat flea (''Xenopsylla cheopis''). It causes the disease plague, which caused the first plague pandemic and the Black Death, the deadliest pandemic in recorded history. Plague takes three main forms: pneumonic, septicemic, and bubonic. ''Yersinia pestis'' is a parasite of its host, the rat flea, which is also a parasite of rats, hence ''Y. pestis'' is a hyperparasite. ''Y. pestis'' was discovered in 1894 by Alexandre Yersin, a Swiss/French physician and bacteriologist from the Pasteur Institute, during an epidemic of the plague in Hong Kong. Yersin was a member of the Pasteur school of thought. Kitasato Shibasaburō, a Japanese bacteriologist who practised Koch's me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longevity
The word " longevity" is sometimes used as a synonym for " life expectancy" in demography. However, the term ''longevity'' is sometimes meant to refer only to especially long-lived members of a population, whereas ''life expectancy'' is always defined statistically as the average number of years remaining at a given age. For example, a population's life expectancy at birth is the same as the average age at death for all people born in the same year (in the case of cohorts). Longevity is best thought of as a term for general audiences meaning 'typical length of life' and specific statistical definitions should be clarified when necessary. Reflections on longevity have usually gone beyond acknowledging the brevity of human life and have included thinking about methods to extend life. Longevity has been a topic not only for the scientific community but also for writers of travel, science fiction, and utopian novels. In fact the legendary fountain of youth appeared in the work of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diurnal Animal
Diurnality is a form of plant and animal behavior characterized by activity during daytime, with a period of sleeping or other inactivity at night. The common adjective used for daytime activity is "diurnal". The timing of activity by an animal depends on a variety of environmental factors such as the temperature, the ability to gather food by sight, the risk of predation, and the time of year. Diurnality is a cycle of activity within a 24-hour period; cyclic activities called circadian rhythms are endogenous cycles not dependent on external cues or environmental factors except for a zeitgeber. Animals active during twilight are crepuscular, those active during the night are nocturnal and animals active at sporadic times during both night and day are cathemeral. Plants that open their flowers during the daytime are described as diurnal, while those that bloom during nighttime are nocturnal. The timing of flower opening is often related to the time at which preferred pollinators a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
