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Yak
The yak (''Bos grunniens''), also known as the Tartary ox, grunting ox, hairy cattle, or domestic yak, is a species of long-haired domesticated cattle found throughout the Himalayan region, the Tibetan Plateau, Tajikistan, the Pamir Mountains, and as far north as Mongolia and Siberia. It is descended from the wild yak (''Bos mutus''). Etymology The English word ''yak'' originates from the . In Tibetan and Balti it refers only to the male of the species, the female being called or in Tibetan and in Balti. In English, as in most other languages that have borrowed the word, ''yak'' is usually used for both sexes, with ''bull'' or ''cow'' referring to each sex separately. Taxonomy Belonging to the genus '' Bos'', yaks are related to cattle (''Bos primigenius''). Mitochondrial DNA analyses to determine the evolutionary history of yaks have been inconclusive. The yak may have diverged from cattle at any point between one and five million years ago, and there is some suggest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siberia
Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states since the lengthy conquest of Siberia, which began with the fall of the Khanate of Sibir in 1582 and concluded with the annexation of Chukotka in 1778. Siberia is vast and sparsely populated, covering an area of over , but home to roughly a quarter of Russia's population. Novosibirsk, Krasnoyarsk, and Omsk are the largest cities in the area. Because Siberia is a geographic and historic concept and not a political entity, there is no single precise definition of its territorial borders. Traditionally, Siberia spans the entire expanse of land from the Ural Mountains to the Pacific Ocean, with the Ural River usually forming the southernmost portion of its western boundary, and includes most of the drainage basin of the Arctic Ocean. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wild Yak
The wild yak (''Bos mutus'') is a large, wild bovine native to the Himalayas. It is the ancestor of the domestic yak (''Bos grunniens''). Taxonomy The ancestor of the wild and domestic yak is thought to have diverged from '' Bos primigenius'' at a point between one and five million years ago. The wild yak is now normally treated as a separate species from the domestic yak (''Bos grunniens''). Based on genomic evidence, the closest relatives of yaks are considered to be bison, which have historically been considered members of their own titular genus, rendering the genus '' Bos'' paraphyletic. Relationships of members of the genus ''Bos'' based on nuclear genomes after Sinding, et al. 2021. Description The wild yak is among the largest extant bovid species. Adults stand about tall at the shoulder, and weigh . The head and body length is , not counting the tail of .Han Jianlin, M. Melletti, J. Burton, 2014, Wild yak (Bos mutus Przewalski, 1883), Ecology, Evolution and Behavio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Bison
The American bison (''Bison bison''; : ''bison''), commonly known as the American buffalo, or simply buffalo (not to be confused with Bubalina, true buffalo), is a species of bison that is endemic species, endemic (or native) to North America. It is one of two extant species of bison, along with the European bison. Its habitat, historical range ''circa'' 9000 BC is referred to as the great bison belt, a tract of rich grassland spanning from Alaska south to the Gulf of Mexico, and east to the Atlantic Seaboard (nearly to the Atlantic tidewater (geographic term), tidewater in some areas), as far north as New York (state), New York, south to Georgia (U.S. state), Georgia, and according to some sources, further south to northern Florida, with sightings in North Carolina near Buffalo Ford on the Catawba River as late as 1750. Two subspecies or ecotypes have been described: the plains bison (''B. b. bison''), smaller and with a more rounded hump; and the wood bison (''B. b. athabascae ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High-altitude Adaptation
Organisms can live at high altitude, either on land, in water, or while flying. Decreased oxygen availability and decreased temperature make life at such altitudes challenging, though many species have been successfully adapted via considerable physiological changes. As opposed to short-term acclimatisation (immediate physiological response to changing environment), high-altitude adaptation means irreversible, evolved physiological responses to high-altitude environments, associated with heritable behavioural and genetic changes. Among vertebrates, only few mammals (such as leaf-eared mice, yaks, ibexes, Tibetan gazelles, vicunas, llamas, mountain goats, etc.) and certain birds are known to have completely adapted to high-altitude environments. Human populations such as some Tibetans, South Americans and Ethiopians live in the otherwise uninhabitable high mountains of the Himalayas, Andes and Ethiopian Highlands respectively. The adaptation of humans to high altitude is an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nikolay Przhevalsky
Nikolay Mikhaylovich Przhevalsky (or Prjevalsky;; , . – ) was a Russian geographer and a renowned explorer of Central and East Asia. Although he never reached his ultimate goal, the city of Lhasa in Tibet, he still travelled through regions then unknown to Westerners, such as northern Tibet (modern Tibet Autonomous Region), Amdo (now Qinghai) and Dzungaria (now northern Xinjiang). He contributed substantially to European knowledge of Central Asian geography. Przhevalsky described several species previously unknown to European science, such as Przewalski's horse, Przewalski's gazelle, and the wild Bactrian camel, all of which are now endangered. He was also a mentor of the explorer Pyotr Kozlov. Biography Przhevalsky was born in the Kimborovo family estate (in the Smolensky Uyezd of the Smolensk Governorate of the Russian Empire) which belonged to his grandfather from his mother's side, a Russian nobleman Aleksei Stepanovich Karetnikov, and his wife Ksenia Davydovna Karet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bison
A bison (: bison) is a large bovine in the genus ''Bison'' (from Greek, meaning 'wild ox') within the tribe Bovini. Two extant taxon, extant and numerous extinction, extinct species are recognised. Of the two surviving species, the American bison, ''B. bison'', found only in North America, is the more numerous. Although colloquially referred to as a buffalo in the United States and Canada, it is only distantly related to the true buffalo. The North American species is composed of two subspecies, the Plains bison, ''B. b. bison'', and the generally more northern wood bison, ''B. b. athabascae''. A third subspecies, the eastern bison (''B. b. pennsylvanicus'') is no longer considered a valid taxon, being a junior synonym of ''B. b. bison''. Historical references to "woods bison" or "wood bison" from the Eastern United States refer to this synonym animal (and to their eastern woodland habitat), not to ''B. b. athabascae'', wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Himalayas
The Himalayas, or Himalaya ( ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the Earth's highest peaks, including the highest, Mount Everest. More than list of highest mountains on Earth, 100 peaks exceeding elevations of above sea level lie in the Himalayas. The Himalayas abut on or cross territories of Himalayan states, six countries: Nepal, China, Pakistan, Bhutan, India and Afghanistan. The sovereignty of the range in the Kashmir region is disputed among India, Pakistan, and China. The Himalayan range is bordered on the northwest by the Karakoram and Hindu Kush ranges, on the north by the Tibetan Plateau, and on the south by the Indo-Gangetic Plain. Some of the world's major rivers, the Indus River, Indus, the Ganges river, Ganges, and the Yarlung Tsangpo River, Tsangpo–Brahmaputra River, Brahmaputra, rise in the vicinity of the Himalayas, and their combined drainage basin is home to some 6 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA
Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the DNA contained in a eukaryotic cell; most of the DNA is in the cell nucleus, and, in plants and algae, the DNA also is found in plastids, such as chloroplasts. Mitochondrial DNA is responsible for coding of 13 essential subunits of the complex oxidative phosphorylation (OXPHOS) system which has a role in cellular energy conversion. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that human mtDNA has 16,569 base pairs and encodes 13 proteins. As in other vertebrates, the human mitochondrial genetic code differs slightly from nuclear DNA. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It als ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foetal Haemoglobin
Fetal hemoglobin, or foetal haemoglobin (also hemoglobin F, HbF, or α2γ2) is the main oxygen carrier protein in the human fetus. HemoglobinF is found in fetal red blood cells, and is involved in transporting oxygen from the mother's bloodstream to organs and tissues in the fetus. It is produced at around 6weeks of pregnancy and the levels remain high after birth until the baby is roughly 2–4months old. HemoglobinF has a different composition than adult forms of hemoglobin, allowing it to bind (or attach to) oxygen more strongly; this in turn enables the developing fetus to retrieve oxygen from the mother's bloodstream, which occurs through the placenta found in the mother's uterus. In the newborn, levels of hemoglobin F gradually decrease and reach adult levels (less than 1% of total hemoglobin) usually within the first year, as adult forms of hemoglobin begin to be produced. Diseases such as beta thalassemias, which affect components of the adult hemoglobin, can delay this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Yak Rider
''The'' is a grammatical article in English, denoting nouns that are already or about to be mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with nouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant sound, and as (homophone of the archaic pronoun ''thee' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subcutaneous Fat
The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, or superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and macrophages. The subcutaneous tissue is derived from the mesoderm, but unlike the dermis, it is not derived from the mesoderm's dermatome region. It consists primarily of loose connective tissue and contains larger blood vessels and nerves than those found in the dermis. It is a major site of fat storage in the body. In arthropods, a hypodermis can refer to an epidermal layer of cells that secretes the chitinous cuticle. The term also refers to a layer of cells lying immediately below the epidermis of plants. Structure * Fibrous bands anchoring the skin to the deep fascia * Collagen and elastin fibers attaching it to the dermis * Fat is absent from the eyelids, clitoris, penis, much of pinna, and scrotum * Blood vessels on route to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
