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Mountain Zebra
The mountain zebra (''Equus zebra'') is a zebra species in the family Equidae, native to southwestern Africa. There are two subspecies, the Cape mountain zebra (''E. z. zebra'') found in South Africa and Hartmann's mountain zebra (''E. z. hartmannae'') found in south-western Angola and Namibia. Taxonomy The mountain zebra comprises two subspecies: In 2004, C. P. Groves and C. H. Bell investigated the taxonomy of the zebras (genus ''Equus'', subgenus ''Hippotigris''). They concluded that the mountain zebra (''Equus zebra zebra'') and Hartmann's mountain zebra (''Equus zebra hartmannae'') are distinct, and suggested that the two would be better classified as separate species, ''Equus zebra'' and ''Equus hartmannae''. However, in a sexual genetic study that included 295 mountain zebra specimens, Moodley and Harley (2005) found nothing to support the separation of the two mountain zebra populations into separate species. They concluded that the Cape mountain zebra and Hartman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing a faunal interchange between the two reg ... [...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 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. Trait inheritance and 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, the organism (e.g. dominance), and within the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forage
Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially as hay or silage. While the term ''forage'' has a broad definition, the term ''forage crop'' is used to define crops, annual or biennial, which are grown to be utilized by grazing or harvesting as a whole crop. Common forages Grasses Grass forages include: *'' Agrostis'' spp. – bentgrasses **''Agrostis capillaris'' – common bentgrass **'' Agrostis stolonifera'' – creeping bentgrass *'' Andropogon hallii'' – sand bluestem *'' Arrhenatherum elatius'' – false oat-grass *'' Bothriochloa bladhii'' – Australian bluestem *'' Bothriochloa pertusa'' – hurricane grass *'' Brachiaria decumbens'' – Surinam grass *'' Brachiaria humidico ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plains Zebra
The plains zebra (''Equus quagga'', formerly ''Equus burchellii''), also known as the common zebra, is the most common and geographically widespread species of zebra. Its range is fragmented, but spans much of southern and eastern Africa south of the Sahara. Six or seven subspecies have been recognised, including the extinct quagga which was thought to be a separate species. More recent research supports variations in zebra populations being clines rather than subspecies. The plains zebra is intermediate in size between the larger Grévy's zebra and the smaller mountain zebra and tends to have broader stripes than both. Great variation in coat patterns exists between clines and individuals. The plain zebra's habitat is generally, but not exclusively, treeless grasslands and savanna woodlands, both tropical and temperate. They generally avoid desert, dense rainforest and permanent wetlands. Zebras are preyed upon by lions and spotted hyenas, Nile crocodiles and, to a lesser exte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountain Zebras
A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher than a hill, typically rising at least 300 metres (1,000 feet) above the surrounding land. A few mountains are isolated summits, but most occur in mountain ranges. Mountains are formed through tectonic forces, erosion, or volcanism, which act on time scales of up to tens of millions of years. Once mountain building ceases, mountains are slowly leveled through the action of weathering, through slumping and other forms of mass wasting, as well as through erosion by rivers and glaciers. High elevations on mountains produce colder climates than at sea level at similar latitude. These colder climates strongly affect the ecosystems of mountains: different elevations have different plants and animals. Because of the less hospitable terrain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Escarpment
An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''escarpment''. Some sources differentiate the two terms, with ''escarpment'' referring to the margin between two landforms, and ''scarp'' referring to a cliff or a steep slope. In this usage an escarpment is a ridge which has a gentle slope on one side and a steep scarp on the other side. More loosely, the term ''scarp'' also describes a zone between a coastal lowland and a continental plateau which shows a marked, abrupt change in elevation caused by coastal erosion at the base of the plateau. Formation and description Scarps are generally formed by one of two processes: either by differential erosion of sedimentary rocks, or by movement of the Earth's crust at a geologic fault. The first process is the more common type: the escarpment is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crossbreed
A crossbreed is an organism with purebred parents of two different breeds, varieties, or populations. ''Crossbreeding'', sometimes called "designer crossbreeding", is the process of breeding such an organism, While crossbreeding is used to maintain health and viability of organisms, irresponsible crossbreeding can also produce organisms of inferior quality or dilute a purebred gene pool to the point of extinction of a given breed of organism. A domestic animal of unknown ancestry, where the breed status of only one parent or grandparent is known, may also be called a crossbreed though the term "mixed breed" is technically more accurate. Outcrossing is a type of crossbreeding used within a purebred breed to increase the genetic diversity within the breed, particularly when there is a need to avoid inbreeding. In animal breeding, ''crossbreeds'' are crosses within a single species, while '' hybrids'' are crosses between different species. In plant breeding terminology, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allopatric
Allopatric speciation () – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow. Various geographic changes can arise such as the movement of continents, and the formation of mountains, islands, bodies of water, or glaciers. Human activity such as agriculture or developments can also change the distribution of species populations. These factors can substantially alter a region's geography, resulting in the separation of a species population into isolated subpopulations. The vicariant populations then undergo genetic changes as they become subjected to different selective pressures, experience genetic drift, and accumulate different mutations in the separated populations' gene pools. The barriers prevent the exchange of genetic information between th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Browsing (herbivory)
Browsing is a type of herbivory in which a herbivore (or, more narrowly defined, a folivore) feeds on leaves, soft shoots, or fruits of high-growing, generally woody plants such as shrubs. This is contrasted with grazing, usually associated with animals feeding on grass or other lower vegetations. Alternatively, grazers are animals eating mainly grass, and browsers are animals eating mainly non-grasses, which include both woody and herbaceous dicots. In either case, an example of this dichotomy are goats (which are primarily browsers) and sheep (which are primarily grazers). Browse The plant material eaten is known as ''browse'' and is in nature taken directly from the plant, though owners of livestock such as goats and deer may cut twigs or branches for feeding to their stock. In temperate regions, owners take browse before leaf fall, then dry and store it as a winter feed supplement. In time of drought, herdsmen may cut branches from beyond the reach of their stock, as fora ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Dimorphism
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most animals and some plants. Differences may include secondary sex characteristics, size, weight, colour, markings, or behavioural or cognitive traits. These differences may be subtle or exaggerated and may be subjected to sexual selection and natural selection. The opposite of dimorphism is ''monomorphism'', which is when both biological sexes are phenotypically indistinguishable from each other. Overview Ornamentation and coloration Common and easily identified types of dimorphism consist of ornamentation and coloration, though not always apparent. A difference in coloration of sexes within a given species is called sexual dichromatism, which is commonly seen in many species of birds and reptiles. Sexual selection leads to the exaggerated ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dewlap
A dewlap is a longitudinal flap of skin or similar flesh that hangs beneath the lower jaw or neck of many vertebrates. More loosely, it can be various similar structures in the neck area, such as those caused by a double chin or the submandibular vocal sac of a frog. More generally, it can be any hanging mass of skin, such as a fold of loose skin on an elderly person's neck, or the wattle of a bird. Dewlaps can be considered as a ''caruncle'', defined as "a small, fleshy excrescence that is a normal part of an animal's anatomy". Etymology The word is first attested in the mid 1300s as ''dewelappe'' ("fold of skin that hangs from the throat of oxen and kine"), from ''lappe'' ("loose piece", from Old English ), but the first element ''*dew(e)-'' is of nebulous origin and meaning; it probably was altered by folk etymology with " dew". Old English had ''fræt-læppa'' in the aforementioned sense (and Middle English ''fresh-lappe''). There also seems to be a cognate to Danish di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hartmanns Mountain Zebra Resting
Ringer's lactate solution (RL), also known as sodium lactate solution, Lactated Ringer’s, and Hartmann's solution, is a mixture of sodium chloride, sodium lactate, potassium chloride, and calcium chloride in water. It is used for replacing fluids and electrolytes in those who have low blood volume or low blood pressure. It may also be used to treat metabolic acidosis and to wash the eye following a chemical burn. It is given by intravenous infusion or applied to the affected area. Side effects may include allergic reactions, high blood potassium, hypervolemia, and high blood calcium. It may not be suitable for mixing with certain medications and some recommend against use in the same infusion as a blood transfusion. Ringer's lactate solution has a lower rate of acidosis as compared with normal saline. Use is generally safe in pregnancy and breastfeeding. Ringer's lactate solution is in the crystalloid family of medications. It is isotonic, i.e. it has the same tonicity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
