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Ancestor
An ancestor, also known as a forefather, fore-elder or a forebear, is a parent or ( recursively) the parent of an antecedent (i.e., a grandparent, great-grandparent, great-great-grandparent and so forth). ''Ancestor'' is "any person from whom one is descended. In law, the person from whom an estate has been inherited." Two individuals have a genetic relationship if one is the ancestor of the other or if they share a common ancestor. In evolutionary theory, species which share an evolutionary ancestor are said to be of common descent. However, this concept of ancestry does not apply to some bacteria and other organisms capable of horizontal gene transfer. Some research suggests that the average person has twice as many female ancestors as male ancestors. This might have been due to the past prevalence of polygynous relations and female hypergamy. Assuming that all of an individual's ancestors are otherwise unrelated to each other, that individual has 2''n'' ancestors in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancestor Veneration
The veneration of the dead, including one's ancestors, is based on love and respect for the deceased. In some cultures, it is related to beliefs that the dead have a continued existence, and may possess the ability to influence the fortune of the living. Some groups venerate their direct, familial ancestors. Certain sects and religions, in particular the Eastern Orthodox Church and Roman Catholic Church, venerate saints as intercessors with God; the latter also believes in prayer for departed souls in Purgatory. Other religious groups, however, consider veneration of the dead to be idolatry and a sin. In European, Asian, Oceanian, African and Afro-diasporic cultures, the goal of ancestor veneration is to ensure the ancestors' continued well-being and positive disposition towards the living, and sometimes to ask for special favours or assistance. The social or non-religious function of ancestor veneration is to cultivate kinship values, such as filial piety, family loyalty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ancestor Worship
The veneration of the dead, including one's ancestors, is based on love and respect for the deceased. In some cultures, it is related to beliefs that the dead have a continued existence, and may possess the ability to influence the fortune of the living. Some groups venerate their direct, familial ancestors. Certain sects and religions, in particular the Eastern Orthodox Church and Roman Catholic Church, venerate saints as intercessors with God; the latter also believes in prayer for departed souls in Purgatory. Other religious groups, however, consider veneration of the dead to be idolatry and a sin. In European, Asian, Oceanian, African and Afro-diasporic cultures, the goal of ancestor veneration is to ensure the ancestors' continued well-being and positive disposition towards the living, and sometimes to ask for special favours or assistance. The social or non-religious function of ancestor veneration is to cultivate kinship values, such as filial piety, family lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Most Recent Common Ancestor
In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The term is also used in reference to the ancestry of groups of genes (haplotypes) rather than organisms. The MRCA of a set of individuals can sometimes be determined by referring to an established pedigree. However, in general, it is impossible to identify the exact MRCA of a large set of individuals, but an estimate of the time at which the MRCA lived can often be given. Such ''time to most recent common ancestor'' (''TMRCA'') estimates can be given based on DNA test results and established mutation rates as practiced in genetic genealogy, or by reference to a non-genetic, mathematical model or computer simulation. In organisms using sexual reproduction, the ''matrilineal MRCA'' and ''patrilineal MRCA'' are the MRCAs of a given population ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Genealogy
Genetic genealogy is the use of genealogical DNA tests, i.e., DNA profiling and DNA testing, in combination with traditional genealogical methods, to infer genetic relationships between individuals. This application of genetics came to be used by family historians in the 21st century, as DNA tests became affordable. The tests have been promoted by amateur groups, such as surname study groups or regional genealogical groups, as well as research projects such as the Genographic Project. As of 2019, about 30 million people had been tested. As the field developed, the aims of practitioners broadened, with many seeking knowledge of their ancestry beyond the recent centuries, for which traditional pedigrees can be constructed. History The investigation of surnames in genetics can be said to go back to George Darwin, a son of Charles Darwin and Charles' first cousin Emma Darwin. In 1875, George Darwin used surnames to estimate the frequency of first-cousin marriages and calcul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Descent
Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. All living beings are in fact descendants of a unique ancestor commonly referred to as the last universal common ancestor (LUCA) of all life on Earth, according to modern evolutionary biology. Common descent is an effect of speciation, in which multiple species derive from a single ancestral population. The more recent the ancestral population two species have in common, the more closely are they related. The most recent common ancestor of all currently living organisms is the last universal ancestor, which lived about 3.9 billion years ago. The two earliest pieces of evidence for life on Earth are graphite found to be biogenic in 3.7 billion-year-old metasedimentary rocks discovered in western Greenland and microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia. All currently living organisms on Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genealogy
Genealogy () is the study of families, family history, and the tracing of their lineages. Genealogists use oral interviews, historical records, genetic analysis, and other records to obtain information about a family and to demonstrate kinship and pedigrees of its members. The results are often displayed in charts or written as narratives. The field of family history is broader than genealogy, and covers not just lineage but also family and community history and biography. The record of genealogical work may be presented as a "genealogy", a "family history", or a "family tree". In the narrow sense, a "genealogy" or a "family tree" traces the descendants of one person, whereas a "family history" traces the ancestors of one person, but the terms are often used interchangeably. A family history may include additional biographical information, family traditions, and the like. The pursuit of family history and origins tends to be shaped by several motives, including the desire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Evolution
Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation tends to exist within any given population as a result of genetic mutation and recombination. Evolution occurs when evolutionary processes such as natural selection (including sexual selection) and genetic drift act on this variation, resulting in certain characteristics becoming more common or more rare within a population. The evolutionary pressures that determine whether a characteristic is common or rare within a population constantly change, resulting in a change in heritable characteristics arising over successive generations. It is this process of evolution that has given rise to biodiversity at every level of biological organisation, including the levels of species, individual organisms, and molecules. The theory of evolut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pedigree Collapse
In genealogy, pedigree collapse describes how reproduction between two individuals who share an ancestor causes the number of distinct ancestors in the family tree of their offspring to be smaller than it could otherwise be. Robert C. Gunderson coined the term; synonyms include implex and the German ''Ahnenschwund'' (loosely translated: "loss of lineage"). Overview Without pedigree collapse, a person's ancestor tree is a binary tree, formed by the person, the parents (2), the grandparents (4), great-grandparents (8), and so on. However, the number of individuals in such a tree grows exponentially and will eventually become impossibly high. For example, a single individual alive today would, over 30 generations going back to the High Middle Ages, have 230 or roughly 1,000 million ancestors, more than the total world population at the time. This paradox is explained by shared ancestors, referred to as pedigree collapse. Instead of consisting of all different individuals, a tree ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the first life forms to appear on Earth, and are present in most of its habitats. Bacteria inhabit soil, water, Hot spring, acidic hot springs, radioactive waste, and the deep biosphere of Earth's crust. Bacteria are vital in many stages of the nutrient cycle by recycling nutrients such as the nitrogen fixation, fixation of nitrogen from the Earth's atmosphere, atmosphere. The nutrient cycle includes the decomposition of cadaver, dead bodies; bacteria are responsible for the putrefaction stage in this process. In the biological communities surrounding hydrothermal vents and cold seeps, extremophile bacteria provide the nutrients needed to sustain life by converting dissolved compounds, such as hydrogen sulp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horizontal Gene Transfer
Horizontal gene transfer (HGT) or lateral gene transfer (LGT) is the movement of genetic material between unicellular and/or multicellular organisms other than by the ("vertical") transmission of DNA from parent to offspring (reproduction). HGT is an important factor in the evolution of many organisms. HGT is influencing scientific understanding of higher order evolution while more significantly shifting perspectives on bacterial evolution. Horizontal gene transfer is the primary mechanism for the spread of antibiotic resistance in bacteria, and plays an important role in the evolution of bacteria that can degrade novel compounds such as human-created pesticides and in the evolution, maintenance, and transmission of virulence. It often involves temperate bacteriophages and plasmids. Genes responsible for antibiotic resistance in one species of bacteria can be transferred to another species of bacteria through various mechanisms of HGT such as transformation, transduction and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Ideally, families offer predictability, structure, and safety as members mature and learn to participate in the community. Historically, most human societies use family as the primary locus of attachment, nurturance, and socialization. Anthropologists classify most family organizations as matrifocal (a mother and her children), patrifocal (a father and his children), conjugal (a wife, her husband, and children, also called the nuclear family), avuncular (a man, his sister, and her children), or extended (in addition to parents and children, may include grandparents, aunts, uncles, or cousins). The field of genealogy aims to trace family lineages through history. The family is also an important economic unit studied in family economics. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Consanguinity
Consanguinity ("blood relation", from Latin '' consanguinitas'') is the characteristic of having a kinship with another person (being descended from a common ancestor). Many jurisdictions have laws prohibiting people who are related by blood from marrying or having sexual relations with each other. The degree of consanguinity that gives rise to this prohibition varies from place to place. Such rules are also used to determine heirs of an estate according to statutes that govern intestate succession, which also vary from jurisdiction to jurisdiction. In some places and time periods, cousin marriage is allowed or even encouraged; in others, it is taboo, and considered to be incest. The degree of relative consanguinity can be illustrated with a ''consanguinity table'' in which each level of lineal consanguinity (''generation'' or '' meiosis'') appears as a row, and individuals with a collaterally consanguineous relationship share the same row. The Knot System is a numerical not ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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