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Ardipithecus is a genus of an extinct hominine that lived during the Late Miocene and Early Pliocene epochs in the Afar Depression, Ethiopia. Originally described as one of the earliest ancestors of humans after they diverged from the chimpanzees, the relation of this genus to human ancestors and whether it is a hominin is now a matter of debate. Two fossil species are described in the literature: A. ramidus, which lived about 4.4 million years ago during the early Pliocene, and A. kadabba, dated to approximately 5.6 million years ago. Initial behavioral analysis indicated that Ardipithecus could be very similar to chimpanzees, however more recent analysis based on canine size and lack of canine sexual dimorphism indicates that Ardipithecus was characterised by reduced aggression, and that they more closely resemble bonobos.
Common descent is a concept in evolutionary biology applicable when one species is the ancestor of two or more species later in time. According to modern evolutionary biology, all living beings could be descendants of a unique ancestor commonly referred to as the last universal common ancestor (LUCA) of all life on Earth.
Homininae, also called "African hominids" or "African apes", is a subfamily of Hominidae. It includes two tribes, with their extant as well as extinct species: 1) the tribe Hominini ―and 2) the tribe Gorillini (gorillas). Alternatively, the genus Pan is sometimes considered to belong to its own third tribe, Panini. Homininae comprises all hominids that arose after orangutans split from the line of great apes. The Homininae cladogram has three main branches, which lead to gorillas, and to humans and chimpanzees via the tribe Hominini and subtribes Hominina and Panina. There are two living species of Panina and two living species of gorillas, but only one extant human species. Traces of extinct Homo species, including Homo floresiensis have been found with dates as recent as 40,000 years ago. Organisms in this subfamily are described as hominine or hominines.
A language family is a group of languages related through descent from a common ancestral language or parental language, called the proto-language of that family. The term "family" reflects the tree model of language origination in historical linguistics, which makes use of a metaphor comparing languages to people in a biological family tree, or in a subsequent modification, to species in a phylogenetic tree of evolutionary taxonomy. Linguists therefore describe the daughter languages within a language family as being genetically related. The divergence of a proto-language into daughter languages typically occurs through geographical separation, with different regional dialects of the proto-language spoken by different speech communities undergoing different language changes and thus becoming distinct languages from each other.
Patrilineality, also known as the male line, the spear side or agnatic kinship, is a common kinship system in which an individual's family membership derives from and is recorded through their father's lineage. It generally involves the inheritance of property, rights, names, or titles by persons related through male kin. This is sometimes distinguished from cognate kinship, through the mother's lineage, also called the spindle side or the distaff side.
Race is a categorization of humans based on shared physical or social qualities into groups generally viewed as distinct within a given society. The term came into common usage during the 16th century, when it was used to refer to groups of various kinds, including those characterized by close kinship relations. By the 17th century, the term began to refer to physical (phenotypical) traits, and then later to national affiliations. Modern science regards race as a social construct, an identity which is assigned based on rules made by society. While partly based on physical similarities within groups, race does not have an inherent physical or biological meaning. The concept of race is foundational to racism, the belief that humans can be divided based on the superiority of one race over another.
In human genetics, the Mitochondrial Eve is the matrilineal most recent common ancestor (MRCA) of all living humans. In other words, she is defined as the most recent woman from whom all living humans descend in an unbroken line purely through their mothers and through the mothers of those mothers, back until all lines converge on one woman.
A family tree, also called a genealogy or a pedigree chart, is a chart representing family relationships in a conventional tree structure. More detailed family trees, used in medicine and social work, are known as genograms.
In human genetics, the Y-chromosomal most recent common ancestor is the patrilineal most recent common ancestor (MRCA) from whom all currently living humans are descended. He is the most recent male from whom all living humans are descended through an unbroken line of their male ancestors. The term Y-MRCA reflects the fact that the Y chromosomes of all currently living human males are directly derived from the Y chromosome of this remote ancestor. The analogous concept of the matrilineal most recent common ancestor is known as "Mitochondrial Eve", the most recent woman from whom all living humans are descended matrilineally. As with "Mitochondrial Eve", the title of "Y-chromosomal Adam" is not permanently fixed to a single individual, but can advance over the course of human history as paternal lineages become extinct.
River Out of Eden: A Darwinian View of Life is a 1995 popular science book by Richard Dawkins. The book is about Darwinian evolution and summarizes the topics covered in his earlier books, The Selfish Gene, The Extended Phenotype and The Blind Watchmaker. It is part of the Science Masters series and is Dawkins's shortest book. It is illustrated by Lalla Ward, Dawkins's wife. The book's name is derived from Genesis 2:10 relating to the Garden of Eden. The King James Version reads "And a river went out of Eden to water the garden; and from thence it was parted, and became into four heads."
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.
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.
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.
The last universal common ancestor (LUCA) is the most recent population from which all organisms now living on Earth share common descent—the most recent common ancestor of all current life on Earth. This includes all cellular organisms, but not necessarily viruses; the origins of viruses are unclear, however it is intriguing that they use the same genetic code as cellular organisms do: LUCA may have harboured a variety of viruses. The LUCA is not the first life on Earth; it may have lived among a diversity of other organisms whose descendants all died out. Rather LUCA is the most recent form from which all surviving life on Earth is descended.
Researchers have investigated the relationship between race and genetics as part of efforts to understand how biology may or may not contribute to human racial categorization.
In genetic genealogy, the identical ancestors point (IAP), or all common ancestors (ACA) point, or genetic isopoint, is the most recent point in a given population's past such that each individual alive at this point either has no living descendants, or is the ancestor of every individual alive in the present. This point lies further in the past than the population's most recent common ancestor (MRCA).
Coalescent theory is a model of how alleles sampled from a population may have originated from a common ancestor. In the simplest case, coalescent theory assumes no recombination, no natural selection, and no gene flow or population structure, meaning that each variant is equally likely to have been passed from one generation to the next. The model looks backward in time, merging alleles into a single ancestral copy according to a random process in coalescence events. Under this model, the expected time between successive coalescence events increases almost exponentially back in time. Variance in the model comes from both the random passing of alleles from one generation to the next, and the random occurrence of mutations in these alleles.
Human evolutionary genetics studies how one human genome differs from another human genome, the evolutionary past that gave rise to the human genome, and its current effects. Differences between genomes have anthropological, medical, historical and forensic implications and applications. Genetic data can provide important insights into human evolution.
In biology, evolution is the process of change in all forms of life over generations, and evolutionary biology is the study of how evolution occurs. Biological populations evolve through genetic changes that correspond to changes in the organisms' observable traits. Genetic changes include mutations, which are caused by damage or replication errors in organisms' DNA. As the genetic variation of a population drifts randomly over generations, natural selection gradually leads traits to become more or less common based on the relative reproductive success of organisms with those traits.
There is evidence for interbreeding between archaic and modern humans during the Middle Paleolithic and early Upper Paleolithic. The interbreeding happened in several independent events that included Neanderthals and Denisovans, as well as several unidentified hominins.
References
- ↑ Jorde, Lynn. "Book Reviews." The American Society of Human Genetics. 2002. Vol. 71: 1484-1485.
- ↑ Rohde, Douglas; Olson, Steve; Chang, Joseph. Modelling the recent common ancestry of all living humans. Nature. 2004: Vol 43: 562-565.
- ↑ Crenson, Matt. "Roots of the human family tree remarkably shallow." The Washington Post. July 2, 2006. F:1.
- ↑ Murphy, Mike. "Tracing Very Long-Term Kinship Networks Using SOCSIM." Demographic Research. 2004 Max-Planck-Gesellschaft. Vol 10 Article 7.
- ↑ Crenson, Matt. "Genealogists Discover Royal Roots for All." washingtonpost.com July 1, 2006.
- ↑ Conniff, Richard. "The Family Tree, Pruned." Smithsonian. July 2007: 90-97.
- ↑ Olson, Steve. Descended from Jesus? Do the math. Los Angeles Times.May 19, 2006. B.13.
