human evolution, theory of the origins of the human species, Homo sapiens. Modern understanding of human origins is derived largely from the findings of paleontology paleontology [Gr.,= study of early beings], science of the life of past geologic periods based on fossil remains. Knowledge of the existence of fossils dates back at least to the ancient Greeks, who appear to have regarded them as the remains of various mythological
..... Click the link for more information. , anthropology anthropology, classification and analysis of humans and their society, descriptively, culturally, historically, and physically. Its unique contribution to studying the bonds of human social relations has been the distinctive concept of culture.
..... Click the link for more information. , and genetics genetics, scientific study of the mechanism of heredity. While Gregor Mendel first presented his findings on the statistical laws governing the transmission of certain traits from generation to generation in 1856, it was not until the discovery and detailed study of
..... Click the link for more information. , and involves the process of natural selection (see Darwinism Darwinism, concept of evolution developed in the mid-19th cent. by Charles Robert Darwin. Darwin's meticulously documented observations led him to question the then current belief in special creation of each species.
..... Click the link for more information. ). Although gaps in the fossil record due to differential preservation prevent the complete specification of the line of human descent, H. sapiens share clear anatomical, genetic, and historic relationships to other primates primate, member of the mammalian order Primates, which includes humans, apes, monkeys, and prosimians, or lower primates. The group can be traced to the late Cretaceous period, where members were forest dwellers.
..... Click the link for more information. . Of all primates, humans bear particularly close affinity to other members of a group known as hominoids, or apes ape, any primate of the subfamily Hominoidea, with the possible exception of humans. The small apes, the gibbon and the siamang, and the orangutan, one of the great apes, are found in SE Asia.
..... Click the link for more information. , which includes orangutans orangutan , an ape, Pongo pygmaeus, found in swampy coastal forests of Borneo and Sumatra. Highly specialized for arboreal life, it usually travels by grasping branches with hands and feet and moving from tree to tree. Adult males are about 4 1-2 ft (1.
..... Click the link for more information. , gibbons gibbon, small ape, genus Hyloblates, found in the forests of SE Asia. The gibbons, including the siamang, are known as the small, or lesser, apes; they are the most highly adapted of the apes to arboreal life.
..... Click the link for more information. , gorillas gorilla, an ape, Gorilla gorilla, native to the lowland and mountain forests of western and central equatorial Africa. It is the largest of the apes, the males reaching a height of 5 to 6 ft (150–190 cm) with a 9-ft (144–cm) arm spread.
..... Click the link for more information. , chimpanzees chimpanzee, an ape, genus Pan, of the equatorial forests of central and W Africa. The common chimpanzee, Pan troglodytes, lives N of the Congo River. Full-grown animals of this species are up to 5 ft (1.
..... Click the link for more information. , and humans. Humans and their immediate ancestors, known as hominids, are notable among hominoids for their bipedal locomotion, slow rate of maturation, large brain size, and, at least among the more recent hominids, the development of a relatively sophisticated capacity for language, tool use, and social activity.

The Evolutionary Tree

Humans are mammals of the Primate order. The earliest primates evolved about 65 million years ago in the geological period known as the Paleocene epoch. They were small-brained, arboreal fruit eaters, similar to modern tree shrews tree shrew, small, arboreal mammal of the family Tupaiidae, found in S Asia. The 17 known species of tree shrews are classified as the order Tupaioidea or Scandentia. Tree shrews superficially resemble squirrels, and are commonly brown, gray, or olive in color.
..... Click the link for more information. . Primates of the Eocene epoch (55 to 38 million years ago) were similar and ancestral to contemporary tarsiers tarsier , small, nocturnal, forest-dwelling prosimian primate, genus Tarsius. There are at least three species found in the Philippines, in Sumatra and Borneo, and in Sulawesi. Tarsiers are about 6 in. (15 cm) long with a 10 in.
..... Click the link for more information. , lemurs lemur , name for prosimians, or lower primates, of two related families, found only on Madagascar and adjacent islands. Lemurs have monkeylike bodies and limbs, and most have bushy tails about as long as the body. They have pointed muzzles and large eyes.
..... Click the link for more information. , and tree shrews, and are classified as lower primates or prosimians. During the late Eocene, the higher primates, or anthropoids, developed from prosimian ancestors and, aided by continental drift continental drift, geological theory that the relative positions of the continents on the earth's surface have changed considerably through geologic time. Though first proposed by American geologist Frank Bursley Taylor in a lecture in 1908, the first detailed theory
..... Click the link for more information. , diverged into New World (or platyrrhine) and Old World (or catarrhine) monkeys monkey, any of a large and varied group of mammals of the primate order. The term monkey includes all primates that do not belong to the categories human, ape, or prosimian; however, monkeys do have certain common features.
..... Click the link for more information. . The branching of Old World monkeys and hominoids apparently occurred in the late Oligocene (38 to 25 million years ago) or early Miocene (25 to 8 million years ago), a time period poorly represented in the fossil record. The lesser apes (gibbons and siamangs) and other hominoid lines diverged about 20 million years ago, while the Asian great apes (the orangutan being the only surviving form) diverged from the African hominoids about 15 to 10 million years ago. Genetic evidence suggests that the ancestral lines of gorillas diverged about 8 million years ago and that chimpanzees and hominids diverged about 5 million years ago.

Hominid Evolution

The earliest known hominids are members of the genus Australopithecus Australopithecus , an extinct genus of the hominid family found in Africa between about 4 and 1 million years ago. At least seven species of australopithecines are now generally recognized, including Australopithecus afarensis, A. africanus, A.
..... Click the link for more information. , the earliest of which date to more than 4 million years ago. Unlike other primates, but like all hominids, australopithecines were bipedal. Their crania, however, were small and apelike, with an average cranial capacity of about 450 cc in the gracile species and 600 cc in the robust forms. Australopithecines that have been considered ancestral in the lineage leading to the human genus Homo include A. afarensis (an important skeleton of which is popularly known as Lucy) and A. africanus. The exact position of these and other early species on the hominid family tree continues to be disputed.

The first member of the genus Homo, a small gracile species known as H. habilis, was present in east Africa at least 2 million years ago. H. habilis was the first hominid to exhibit the marked expansion of the brain (with an average cranial capacity of about 750 cc) that would become a hallmark of subsequent hominid evolutionary history. By about 1.6 million years ago, H. habilis had evolved into a larger, more robust, and larger-brained species known as Homo erectus Homo erectus , extinct hominid living between 1.6 million and 250,000 years ago. Homo erectus is thought to have evolved in Africa from H. habilis, the first member of the genus Homo. Anatomically and physiologically, H.
..... Click the link for more information. . Cranial capacities ranged from about 900 cc in early specimens to 1050 cc in later ones. H. erectus persisted for well over a million years and migrated off the African continent into Asia, Indonesia, and Europe.

Between 500,000 and 250,000 years ago, H. erectus evolved into H. sapiens. Transitional forms between H. erectus and H. sapiens are referred to as archaic H. sapiens. With the exception of H. sapiens neandertalensis (see Neanderthal man Neanderthal man or Neandertal man , a subspecies of Homo sapiens, the species to which contemporary humans belong, known as H. sapiens neandertalensis after Neanderthal, Germany, the valley where the first specimen was found.
..... Click the link for more information. ), no additional subspecies are recognized. Indeed, some scientists consider Neanderthal a separate species. Archaic H. sapiens changed gradually, becoming somewhat larger, more gracile and larger-brained through time. Cranial capacity, for example, increased from about 1150 cc in early transitional forms to the current world average of just over 1350 cc. By 150,000 years ago in Africa and Asia and 28,000 years ago in Europe (see Cro-Magnon man Cro-Magnon man , an early Homo sapiens (the species to which modern humans belong) that lived about 40,000 years ago. Skeletal remains and associated artifacts of the of the Aurignacian culture were first found in 1868 in Les Eyzies, Dordogne, France.
..... Click the link for more information. ), the transition to H. sapiens was complete, and fully modern humans became the single surviving hominid species.

The Evolution of Culture

Among hominids, a parallel evolutionary process involving increased intelligence and cultural complexity is apparent in the material record. Evidence of greater behavioral flexibility and adaptability presumably reflects the decreased influence of genetically encoded behaviors and the increased importance of learning and social interaction in transmitting and maintaining behavioral adaptations (see culture culture, in anthropology, the integrated system of socially acquired values, beliefs, and rules of conduct which delimit the range of accepted behaviors in any given society. Cultural differences distinguish societies from one another.
..... Click the link for more information. ). Because the organization of neural circuitry is more significant than overall cranial capacity in establishing mental capabilities, direct inferences from the fossil record are likely to be misleading. Contemporary humans, for example, exhibit considerable variability in cranial capacity (1150 cc to 1600 cc), none of which is related to intelligence.

Tool use was once thought to be the hallmark of members of the genus Homo, beginning with H. habilis, but is now known to be common among chimpanzees. The earliest stone tools of the lower Paleolithic, known as Oldowan tools and dating to about 2 to 2.5 million years ago, were once thought to have been manufactured by H. habilis. Recent finds suggest that Oldowan tools may also have been made by robust australopithecines. The simultaneous emergence of H. erectus and the more complex Achuelian tool tradition may indicate shifting adaptations as much as increased intelligence.

While it is clear that H. erectus was much more versatile than any of its predecessors, adapting its technologies and behaviors to diverse environmental conditions, the extent and limitations of its intellectual endowment remain a subject of heated debate. This is also the case for both archaic H. sapiens and Neanderthals, the latter associated with the more sophisticated technologies of the middle Paleolithic. However impressive the achievements of H. erectus and early H. sapiens, most material remains predating 40,000 years ago reflect utilitarian concerns. Nonetheless, there is now scattered African archaeological evidence from before that time (in one case as early as 90,000 years ago) of the production by H. sapiens of beads and other decorative work, perhaps indicating a gradual development of the aesthetic concerns and other symbolic thinking characteristic of later human societies. Whether the emergence of modern H. sapiens corresponds to the explosion of technological innovations and artistic activities associated with Cro-Magnon culture or was a more prolonged process of development is a subject of archaeological debate.

Bibliography

See R. Lewin, Human Evolution (2d ed. 1989) and, with R. Leakey, Origins Reconsidered (1992); I. Tattersall, The Fossil Trail: How We Know What We Think We Know about Human Evolution (1995); A. Walker and P. Shipman, The Wisdom of the Bones: In Search of Human Origins (1996); C. Stringer and R. McKie, African Exodus: The Origins of Modern Humanity (1997); L. R. Berger and B. Hilton-Barber, In the Footsteps of Eve: The Mystery of Human Origins (2000); I. Tattersall and J. H. Schwartz, Extinct Humans (2000).

human evolution

Evolution of modern human beings from extinct nonhuman and humanlike forms. Genetic evidence points to an evolutionary divergence between the lineages of humans and the great apes on the African continent 8–5 million years ago (mya). The earliest fossils considered to be remains of hominins (members of the human lineage) date to at least 4 mya in Africa; they are classified as genus Australopithecus. The next major evolutionary stage, Homo habilis, inhabited sub-Saharan Africa about 2–1.5 mya. Homo habilis appears to have been supplanted by a taller and more humanlike species, Homo erectus, which lived from c. 1,700,000 to 200,000 years ago, gradually migrating into Asia and parts of Europe. Between c. 600,000 and 200,000 years ago, Homo heidelbergensis, sometimes called archaic Homo sapiens, lived in Africa, Europe, and perhaps parts of Asia. Having features resembling those of both H. erectus and modern humans, H. heidelbergensis may have been an ancestor of modern humans and also of the Neanderthals (H. neanderthalensis), who inhabited Europe and western Asia from c. 200,000 to 28,000 years ago. Fully modern humans (H. sapiens) seem to have emerged in Africa only c. 150,000 years ago, perhaps having descended directly from H. erectus or from an intermediate species such as H. heidelbergensis.

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No references found			Byline: ANI London, November 19 (ANI): Scientists have discovered that a cannibalistic ritual in which the brains of dead tribes people were eaten by their relatives has triggered one of the most striking examples of rapid human evolution on record. Brain-eating ritual in tribes trigger striking example of rapid human ... by Asian News International On November 3, 10, and 17, PBS's NOVA premieres "Becoming Human," a three-part special on human evolution that combines interviews with world-renowned anthropologists and paleoanthropologists and the most recent, groundbreaking discoveries about our earliest ancestors to present a comprehensive picture of our human past. 150th anniversary of the publishing of Charles Darwin's On the Origin ... by Gajewski, Karen Ann / The Humanist David Pilbeam, of Harvard's Peabody Museum of Archaeology and Ethnology, said: "This is one of the most important discoveries for the study of human evolution. Hello, Mum! ARDI OUSTS LUCY AS OUR 1st ANCESTOR by The Mirror (London, England)			Hull, John Hull, William hulless buckwheat Hulling Mill Hulman, Tony Hulse, Russell A. Hulse, Russell Alan hulsite Hulun Hulutao Hulwan Hum hum bar hum modulation hum-bucking coil huma Huma Ho human human authentication human biogeography human chorionic gonadotropin human community Human Constitution human ecology human engineering human evolution Human Factors Human Genetics Human Genome Project human geography human granulocytic ehrlichiosis human growth hormone human immunodeficiency virus Human Interface Device Human Interface Technology Laboratory human leukocyte antigen human measles immune serum Human Migration Human Morphology human myeloma protein human nature human papillomavirus Human Relations Theory human resources human rights human sacrifice human T-lymphotropic virus type 1 human T-lymphotropic virus type 2 human T-lymphotropic virus type 3 human threadworm Human Towers of Valls			Human equality Human equality Human equality Human Equilibrative Nucleoside Transporter Human Equilibrative Nucleoside Transporter 1 Human Equivalent Concentration Human Equivalent Dose Human Era Human Eradication Mode Humán Eroforrás Fejlesztési Operatív Program Human Error Assessment Reduction Technique Human Error Probability Human Error, Safety and Systems Development human erythrocyte agglutination test human erythrocyte agglutination test human erythrocyte agglutination test human erythrocyte agglutination test Human Erythrocyte Aglutination Test Human Erythrocyte Glucose Transporter Human Erythroid Burst-Stimulating Activity Human Erythroxyte Carbonic Anhydrase B Human Esophageal Epithelial Cells Human Esophageal Microvascular Endothelial Cells Human Esophageal Smooth Muscle Cells Human Estrogen Related Receptor-2 Human Estrogen-Related Receptor 1 Human Ether-a-Go-go Related Gene Human Ethics Advisory Group Human EVER1 Disease human evolution Human Evolution Research Center Human Evolutionary Behavioral Sciences Human Exceptionalism Paradigm Human execution Human execution Human execution Human execution Human Experience Development Human Experimental and Research Data Records Human Exploitation Team Human Exploration and Development of Space Human Exploration Initiative Human Exploration Transfer Stage Human Exposure & Atmospheric Sciences Division Human Exposure Assessment Location Human Exposure Modeling Human Exposure Research Organisations Exchange Human Exposure Tiered Risk Assessment Human Exposure to Soil Pollutants Human Exposure/Rodent Potency Human eye Human eye Human eye Human eye Human eyelid Human eyelid Human eyelid human face Human factor Human factor