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Genetic Isolate
Introduction Geographic isolation or other factors that prevent reproduction have resulted in a population of organisms with a change in genetic diversity and ultimately leads to the genetic isolation of species. Genetic isolates form new species through an evolutionary process known as speciation. Today, all the species diversity present on earth is the product of genetic isolate and evolution. The current distribution of genetic differences and isolation within and among populations is also influenced by genetic processes, which can give significant input into evolution's basic principles. The resulting genetic diversity within a species' distribution range is frequently unequally distributed, and large disparities can occur at the series of ranges when population dispersion and isolation are critical for species survival. The interrelationship of genetic drift, gene flow, and natural selection determines the level and dispersion of genetic differences between populations and am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organism
In biology, an organism () is any living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy into groups such as multicellular animals, plants, and fungi; or unicellular microorganisms such as protists, bacteria, and archaea. All types of organisms are capable of reproduction, growth and development, maintenance, and some degree of response to stimuli. Beetles, squids, tetrapods, mushrooms, and vascular plants are examples of multicellular organisms that differentiate specialized tissues and organs during development. A unicellular organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate domains – bacteria and archaea. Eukaryotic organisms are characterized by the presence of a membrane-bound cell nucleus and contain additional membrane-bound compartments called organelles (such as mitochondria in animals and plants ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitcairn Islands
The Pitcairn Islands (; Pitkern: '), officially the Pitcairn, Henderson, Ducie and Oeno Islands, is a group of four volcanic islands in the southern Pacific Ocean that form the sole British Overseas Territory in the Pacific Ocean. The four islands—Pitcairn, Henderson, Ducie and Oeno—are scattered across several hundred miles of ocean and have a combined land area of about . Henderson Island accounts for 86% of the land area, but only Pitcairn Island is inhabited. The islands nearest to the Pitcairn Islands are Mangareva (of French Polynesia) at 688 km to the west and Easter Island at 1,929 km to the east. The Pitcairn Islanders are a biracial ethnic group descended mostly from nine ''Bounty'' mutineers and a handful of Tahitian consorts—as is still apparent from the surnames of many of the islanders. The mutiny and its aftermath have been the subject of many books and films. As of January 2020, the territory had only 47 permanent inhabitants. History Polyn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Language Isolate
Language isolates are languages that cannot be classified into larger language families. Korean and Basque are two of the most common examples. Other language isolates include Ainu in Asia, Sandawe in Africa, and Haida in North America. The number of language isolates is unknown. A language isolate is unrelated to any other, which makes it the only language in its own language family. It is a natural language with no demonstrable genealogical (or "genetic") relationships—one that has not been demonstrated to descend from an ancestor common with any other language. One explanation for the existence of language isolates is that they might be the last remaining branch of a larger language family. The language possibly had relatives in the past which have since disappeared without being documented. Another explanation for language isolates is that they developed in isolation from other languages. This explanation mostly applies to sign languages that have arisen independently ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mitochondrial DNA
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA is only a small portion of the DNA in a eukaryotic cell; most of the DNA can be found in the cell nucleus and, in plants and algae, also in plastids such as chloroplasts. Human mitochondrial DNA was the first significant part of the human genome to be sequenced. This sequencing revealed that the human mtDNA includes 16,569 base pairs and encodes 13 proteins. Since animal mtDNA evolves faster than nuclear genetic markers, it represents a mainstay of phylogenetics and evolutionary biology. It also permits an examination of the relatedness of populations, and so has become important in anthropology and biogeography. Origin Nuclear and mitochondrial DNA are thought to be of separate evolutionary origin, with the mtDNA being derive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Giraffe
The giraffe is a large African hoofed mammal belonging to the genus ''Giraffa''. It is the tallest living terrestrial animal and the largest ruminant on Earth. Traditionally, giraffes were thought to be one species, '' Giraffa camelopardalis'', with nine subspecies. Most recently, researchers proposed dividing them into up to eight extant species due to new research into their mitochondrial and nuclear DNA, as well as morphological measurements. Seven other extinct species of ''Giraffa'' are known from the fossil record. The giraffe's chief distinguishing characteristics are its extremely long neck and legs, its horn-like ossicones, and its spotted coat patterns. It is classified under the family Giraffidae, along with its closest extant relative, the okapi. Its scattered range extends from Chad in the north to South Africa in the south, and from Niger in the west to Somalia in the east. Giraffes usually inhabit savannahs and woodlands. Their food source is leaves, fru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finland
Finland ( fi, Suomi ; sv, Finland ), officially the Republic of Finland (; ), is a Nordic country in Northern Europe. It shares land borders with Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland across Estonia to the south. Finland covers an area of with a population of 5.6 million. Helsinki is the capital and largest city, forming a larger metropolitan area with the neighbouring cities of Espoo, Kauniainen, and Vantaa. The vast majority of the population are ethnic Finns. Finnish, alongside Swedish, are the official languages. Swedish is the native language of 5.2% of the population. Finland's climate varies from humid continental in the south to the boreal in the north. The land cover is primarily a boreal forest biome, with more than 180,000 recorded lakes. Finland was first inhabited around 9000 BC after the Last Glacial Period. The Stone Age introduced several differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Finns
Finns or Finnish people ( fi, suomalaiset, ) are a Baltic Finnic ethnic group native to Finland. Finns are traditionally divided into smaller regional groups that span several countries adjacent to Finland, both those who are native to these countries as well as those who have resettled. Some of these may be classified as separate ethnic groups, rather than subgroups of Finns. These include the Kvens and Forest Finns in Norway, the Tornedalians in Sweden, and the Ingrian Finns in Russia. Finnish, the language spoken by Finns, is closely related to other Balto-Finnic languages, e.g. Estonian and Karelian. The Finnic languages are a subgroup of the larger Uralic family of languages, which also includes Hungarian. These languages are markedly different from most other languages spoken in Europe, which belong to the Indo-European family of languages. Native Finns can also be divided according to dialect into subgroups sometimes called '' heimo'' (lit. ''tribe''), although ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sardinians
The Sardinians, or Sards ( sc, Sardos or ; Italian and Sassarese: ''Sardi''; Gallurese: ''Saldi''), are a Romance language-speaking ethnic group native to Sardinia, from which the western Mediterranean island and autonomous region of Italy derives its name. Etymology Not much can be gathered from the classical literature about the origins of the Sardinian people. The ethnonym "S(a)rd" belongs to the Pre-Indo-European linguistic substratum, and whilst they might have derived from the Iberians, the accounts of the old authors differ greatly in this respect. The oldest written attestation of the ethnonym is on the Nora stone, where the word ''Šrdn'' (''Shardan'') bears witness to its original existence by the time the Phoenician merchants first arrived to the Sardinian shores. According to Timaeus, one of Plato's dialogues, Sardinia and its people as well, the "Sardonioi" or "Sardianoi" (''Σαρδονιοί'' or ''Σαρδιανοί''), might have been named after "Sard ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tristan Da Cunha
Tristan da Cunha (), colloquially Tristan, is a remote group of volcanic islands in the South Atlantic Ocean. It is the most remote inhabited archipelago in the world, lying approximately from Cape Town in South Africa, from Saint Helena and from the Falkland Islands. The territory consists of the inhabited island, Tristan da Cunha, which has a diameter of roughly and an area of ; the wildlife reserves of Gough Island and Inaccessible Island; and the smaller, uninhabited Nightingale Islands. , the main island has 250 permanent inhabitants, who all carry British Overseas Territories citizenship. The other islands are uninhabited, except for the South African personnel of a weather station on Gough Island. Tristan da Cunha is a British Overseas Territory with its own constitution. There is no airstrip on the main island; the only way of travelling in and out of Tristan is by boat, a six-day trip from South Africa. History Discovery The uninhabited islands were fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Speciation
Speciation is the evolutionary process by which populations evolve to become distinct species. The biologist Orator F. Cook coined the term in 1906 for cladogenesis, the splitting of lineages, as opposed to anagenesis, phyletic evolution within lineages. Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book ''On the Origin of Species''. He also identified sexual selection as a likely mechanism, but found it problematic. There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, parapatric, and sympatric. Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments. Whether genetic drift is a minor or major contributor to speciation is the subject of much ongoing discussion. Rapid sympatric speciation can take place through polyploidy, such as by doubling of chromosome numb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dog Breeding
Dog breeding is the practice of mating selected dogs with the intention of maintaining or producing specific qualities and characteristics. When dogs reproduce without such human intervention, their offspring's characteristics are determined by natural selection, while "dog breeding" refers specifically to the artificial selection of dogs, in which dogs are intentionally bred by their owners. Breeding relies on the science of genetics, hence a breeder who is knowledgeable on canine genetics, health, and the intended purpose of the dogs attempts to breed suitable dogs. Terminology The female parent of puppies is referred to as the ''dam'' and the male parent is referred to as the ''sire''. A litter consists of the puppies born from the same pregnancy. A ''whelp'' is a newborn puppy and giving birth to dogs is called ''whelping''. Dogs commonly give birth in a ''whelping box'', a simple box or pen provided to the dam to help shelter and contain the puppies. A person who intentio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sympatric Speciation
Sympatric speciation is the evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region. In evolutionary biology and biogeography, sympatric and sympatry are terms referring to organisms whose ranges overlap so that they occur together at least in some places. If these organisms are closely related (e.g. sister species), such a distribution may be the result of sympatric speciation. Etymologically, sympatry is derived from the Greek roots ("together") and ("homeland"). The term was coined by Edward Bagnall Poulton in 1904, who explains the derivation. Sympatric speciation is one of three traditional geographic modes of speciation.Futuyma, D. J. 2009. ''Evolution'' (2nd edition). Sinauer Associates, Inc. Allopatric speciation is the evolution of species caused by the geographic isolation of two or more populations of a species. In this case, divergence is facilitated by the absence of gene flow. Parapatric specia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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