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Chimpanzee–human Last Common Ancestor
The chimpanzee–human last common ancestor (CHLCA) is the last common ancestor shared by the extant ''Homo'' (human) and '' Pan'' (chimpanzee and bonobo) genera of Hominini. Estimates of the divergence date vary widely from thirteen to five million years ago. In human genetic studies, the CHLCA is useful as an anchor point for calculating single-nucleotide polymorphism (SNP) rates in human populations where chimpanzees are used as an outgroup, that is, as the extant species most genetically similar to ''Homo sapiens''. Despite extensive research, no direct fossil evidence of the CHLCA has been discovered. Fossil candidates like ''Sahelanthropus tchadensis,'' ''Orrorin tugenensis'', and ''Ardipithecus ramidus'' have been debated as either being early hominins or close to the CHLCA. However, their classification remains uncertain due to incomplete evidence Taxonomy The taxon tribe ''Hominini'' was proposed to separate humans (genus ''Homo'') from chimpanzees ('' Pan'') and g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Last Common Ancestor
A most recent common ancestor (MRCA), also known as a last common ancestor (LCA), is the most recent individual from which all organisms of a set are inferred to have descended. The most recent common ancestor of a higher taxon is generally assumed to have been a species. The term is also used in reference to the ancestry of groups of genes (haplotypes) rather than organisms. The ancestry of a set of individuals can sometimes be determined by referring to an established pedigree, although this may refer only to patrilineal or matrilineal lines for sexually-reproducing organisms with two parents, four grandparents, etc. 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- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Wrangham
Richard Walter Wrangham (born 1948) is an English anthropologist and primatologist; he is Professor of Biological Anthropology at Harvard University. His research and writing have involved ape behavior, human evolution, violence, and cooking. Biography Wrangham was born in Leeds, Yorkshire. Following his years on the faculty of the University of Michigan, he became the Ruth Moore Professor of Biological Anthropology at Harvard University and his research group is now part of the newly established Department of Human Evolutionary Biology. He is a MacArthur fellow. He is co-director of the Kibale Chimpanzee Project, the long-term study of the Kanyawara chimpanzees in Kibale National Park, Uganda. His research culminates in the study of human evolution in which he draws conclusions based on the behavioural ecology of apes. As a graduate student, Wrangham studied under Robert Hinde and Jane Goodall. Wrangham is known predominantly for his work in the ecology of primate social ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Rift Valley, Kenya
The Great Rift Valley is part of an intra-continental ridge system that runs through Kenya from north to south. It is part of the Gregory Rift, the eastern branch of the East African Rift, which starts in Tanzania to the south and continues northward into Ethiopia. It was formed on the "Kenyan Dome", a geographical upwelling created by the interactions of three major tectonics: the Arabian, Nubian, and Somalian plates. In the past, it was seen as part of a " Great Rift Valley" that runs from Madagascar to Syria. Most of the valley falls within the former Rift Valley Province. The valley contains the Cherangani Hills and a chain of volcanoes, some of which are still active. The climate is mild, with temperatures usually below . Most rain falls during the March–June and October–November periods. The Tugen Hills to the west of Lake Baringo contain fossils preserved in lava flows from the period 14 to 4 million years ago. The relics of many hominids, ancestors of humans, have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kenya
Kenya, officially the Republic of Kenya, is a country located in East Africa. With an estimated population of more than 52.4 million as of mid-2024, Kenya is the 27th-most-populous country in the world and the 7th most populous in Africa. Kenya's capital and largest city is Nairobi. Its second-largest and oldest city is Mombasa, a major port city located on Mombasa Island. Other major cities within the country include Kisumu, Nakuru & Eldoret. Going clockwise, Kenya is bordered by South Sudan to the northwest (though much of that border includes the disputed Ilemi Triangle), Ethiopia to the north, Somalia to the east, the Indian Ocean to the southeast, Tanzania to the southwest, and Lake Victoria and Uganda to the west. Kenya's geography, climate and population vary widely. In western, rift valley counties, the landscape includes cold, snow-capped mountaintops (such as Batian, Nelion and Point Lenana on Mount Kenya) with vast surrounding forests, wildlife and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argon–argon Dating
Argon–argon (or 40Ar/39Ar) dating is a radiometric dating method invented to supersede Potassium-argon dating, potassiumargon (K/Ar) dating in accuracy. The older method required splitting samples into two for separate potassium and argon measurements, while the newer method requires only one rock fragment or mineral grain and uses a single measurement of isotopes of argon, argon isotopes. 40Ar/39Ar dating relies on neutron irradiation from a nuclear reactor to convert a stable form of potassium (39K) into the radioactive 39Ar. As long as a standard of known age is co-irradiated with unknown samples, it is possible to use a single measurement of argon isotopes to calculate the 40K/40Ar* ratio, and thus to calculate the age of the unknown sample. 40Ar* refers to the radiogenic 40Ar, i.e. the 40Ar produced from radioactive decay of 40K. 40Ar* does not include atmospheric argon adsorbed to the surface or inherited through diffusion and its calculated value is derived from measuring t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australopithecus Anamensis
''Australopithecus anamensis'' is a hominin species that lived roughly between 4.3 and 3.8 million years ago, and is the oldest known ''Australopithecus'' species, Nearly 100 fossil specimens of ''A. anamensis'' are known from Kenya and Ethiopia, representing over 20 individuals. The first fossils of ''A. anamensis'' discovered are dated to around 3.8 and 4.2 million years ago and were found in Kanapoi and Allia Bay in northern Kenya. '' A. afarensis'' is normally accepted to have emerged within this lineage. However, ''A. anamensis'' and ''A. afarensis'' appear to have lived side-by-side for at least some period of time, and whether the lineage that led to extant humans emerged in ''A. afarensis'', or directly in ''A. anamensis'' is not fully settled. Fossil evidence determines that ''Australopithecus anamensis'' is the earliest hominin species in the Turkana Basin, but likely co-existed with ''afarensis'' towards the end of its existence. ''A. anamensis'' and ''A. afarensis'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southeast Europe
Southeast Europe or Southeastern Europe is a geographical sub-region of Europe, consisting primarily of the region of the Balkans, as well as adjacent regions and Archipelago, archipelagos. There are overlapping and conflicting definitions of the region, due to political, economic, historical, cultural, and geographical considerations. Sovereign state, Sovereign states and territories that may be included in the region are Albania, Bosnia and Herzegovina, Bulgaria, Croatia (alternatively placed in Central Europe), Greece (alternatively placed in the broader region of Southern Europe), Kosovo, Montenegro, North Macedonia, Romania (alternatively placed in Eastern Europe), Serbia, and the East Thrace, European part of Turkey (alternatively placed in the broader region of Southern Europe, also in West Asia, Western Asia with the rest of the country). Sometimes, Cyprus (most often placed in West Asia), Hungary (most often placed in Central Europe), Moldova (most often placed in Easte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graecopithecus
''Graecopithecus'' is an extinct genus of hominid that lived in southeast Europe during the late Miocene around 7.2 million years ago. Originally identified by a single lower jawbone bearing teeth found in Pyrgos Vasilissis, Athens, Greece, in 1944, other teeth were discovered from Azmaka quarry in Bulgaria in 2012. With only little and badly preserved materials to reveal its nature, it is considered as "the most poorly known European Miocene hominoids." The creature was popularly nicknamed 'El Graeco' (word play on the Greek-Spanish painter El Greco) by scientists. In 2017, an international team of palaeontologists led by Madelaine Böhme of the Eberhard-Karls-University Tübingen, Germany, published a controversial analysis of the teeth and age of the specimens, and came to the conclusion that it could be the oldest hominin, meaning that it could be the oldest direct ancestors of humans after splitting from that of the chimpanzees. Their simultaneous study also claimed tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ardipithecus
''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 (late Miocene). 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. Some analyses describe ''Australopithecus'' as being sister to ''Ardipithecus ramidus'' specifically. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hominine
Homininae (the hominines) is a subfamily of the family Hominidae (hominids). (The Homininae——encompass humans, and are also called "African hominids" or "African apes".) This subfamily includes two tribes, Hominini and Gorillini, both having extant (or living) species as well as extinct species. Tribe Hominini includes: the extant genus ''Homo'', which comprises only one extant species—the modern humans (''Homo'' sapiens), and numerous extinct human species; and the extant genus '' Pan'', which includes two extant species, chimpanzees and bonobos. Tribe Gorillini (gorillas) contains one extant genus, Gorilla, with two extant species, with variants, and one known extinct genus. Alternatively, the genus ''Pan'' is considered by some to belong, instead of to a subtribe Panina, to its own separate tribe, (''so-called'') "Panini"—which would be a third tribe for Homininae. Some classification schemes provide a more comprehensive account of extinct groups—(see section "Taxo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sahelanthropus Tchadensis
''Sahelanthropus'' is an extinct genus of hominid dated to about during the Late Miocene. The type species, ''Sahelanthropus tchadensis'', was first announced in 2002, based mainly on a partial cranium, nicknamed ''Toumaï'', discovered in northern Chad. The definitive phylogenetic position of ''Sahelanthropus'' within hominids is uncertain. It was initially described as a possible hominin ancestral to both humans and chimpanzees, but subsequent interpretations suggest that it could be an early member of the tribe Gorillini or a stem-hominid outside the hominins. Examinations on the postcranial skeleton of ''Sahelanthropus'' also indicated that this taxon was not a habitual biped. Taxonomy Discovery Four employees of the Centre National d'Appui à la Recherche (CNAR, National Research Support Center) of the Ministry of Higher Education of the Republic of Chad, three Chadians (Ahounta Djimdoumalbaye, Fanoné Gongdibé and Mahamat Adoum) and one French (Alain Beauvilain) collecte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
