HOMO SAPIENTS SAPIENT by: RICHARD J.KOSCIEJEW

HOMO SAPIENTS SAPIENT
Presented By: RICHARD J.KOSCIEJEW
Early hominids made stone artifacts either by smashing rocks between a hammer and anvil (known as the bipolar technique) to produce usable pieces or by a more controlled process termed flaking, in which stone chips were fractured away from a larger rock by striking it with a hammer of stone or other hard material. Subsequently, during the lingering existence of say 10,000 years, the diversely in techniques for producing masonry artifacts - including pecking, grinding, sawing, and boring - became additionally familiar. The best rocks for flaking tended to be hard, fine-grained, or amorphous (having no crystal structure) rocks, including lava, obsidian, ignimbrite, flint, chert, quartz, silicified limestone, quartzite, and indurated shale. Ground stone tools could be made on a wider range of raw material types, including coarser grained rock such as granite.
 Flaking produces several different types of stone artifacts, which archaeologists look forward to at prehistoric sites. The parent pieces of rock from which chips have been detached are called cores, and the chips removed from cores are called flakes. A flake that has had yet smaller flakes removed from one or more edges to sharpen or shape it is known as a retouched piece. The stone used to knock flakes from cores is called a hammerstone or a precursor. Other flaking artifacts include fragments and chunks, most of which are broken cores and flakes.
 The terms culture and industries both refer to a system of technology (Toolmaking technique, for example) shared by different Stone Age sites of the same broad time. Experts now prefer to use the term industry instead of culture to refer to these shared Stone Age systems.
 Archaeologists have divided the Stone Age into different stages, each characterized by different types of tools or tool-manufacturing techniques. The stages also imply broad time frames and are perceived as stages of human cultural development. The most widely used designations for the successive stages are Paleolithic (Old Stone Age), Mesolithic (Middle Stone Age), and Neolithic (New Stone Age). British naturalist Sir John Lubbock in 1865 defined the Paleolithic stage as the period in which stone tools were chipped or flaked. He defined the Neolithic as the stage in which ground and polished stone axes became prevalent. These two stages also were associated with different economic and subsistence strategies: Paleolithic peoples were hunter-gatherers while Neolithic peoples were farmers. Archaeologists subsequently identified a separate stage of stone tool working in Eurasia and Africa between the Paleolithic and the Neolithic, called the Mesolithic. This period is characterized by the creation of microliths, small, geometric-shaped stone artifacts attached to wood, antler, or bone to form implements such as arrows, spears, or scythes. Microliths began appearing between 15,000 and 10,000 years ago at the end of the Pleistocene Ice Age.
 The Paleolithic/Mesolithic/Neolithic division system was first applied only to sites in Europe, but is now widely used (with some modification) to refer to prehistoric human development in much of Asia, Africa, and Australasia. Different terminology is often used to describe the cultural-historical chronology of the Americas, which humans did not reach until some point between 20,000 and 12,000 years ago. However, there is a general similarity, the transitional form of flaked stone tools are  associated with prehistoric hunter-gatherers to both flaked and ground stone tools associated with the rise of early farming communities. The period in the Americas up to the end of the Pleistocene Ice Age about 10,000 years ago, when most humans were hunter-gatherers, is called Paleo-Indian and the subsequent, post-glacial period is known as Archaic.
 Archaeologists subdivide the Paleolithic into the Lower Paleolithic (the earliest phase), Middle Paleolithic, and Upper Paleolithic (the later phase), based upon the presence or absence of certain classes of stone artifacts. The Lower Paleolithic dates from approximately 2.5 million years ago until about 200,000 years ago. It includes the earliest record of human toolmaking and documents much of the evolutionary history of the genus Homo from its origins in Africa to its spread into Eurasia. Two successive toolmaking industries characterize the Lower Paleolithic: the Oldowan and the Acheulean.
 The Oldowan industry was named by British Kenyan anthropologists Louis Leakey and Mary Leakey for early archaeological sites found at Olduvai Gorge in northern Tanzania. It is also sometimes called the chopper-core or pebble-tool industry. Simple stone artifacts made from small stones or blocks of stone characterize the Oldowan industry. Mary Leakey classified Oldowan artifacts as either heavy-duty tools or light-duty tools, as both their classifications deemed to be heavy-duty tools, which include core types such as choppers, discoids, polyhedrons, and heavy-duty scrapers. Many of these cores may have been produced to generate sharp-edged flakes, but some could have been used for chopping or scraping activities as well. Light-duty tools include retouched forms such as smaller scrapers, awls (sharp, pointed tools for punching holes in animal hides or wood), and burins (chisel-like flint tools used for engraving and cutting). Oldowan techniques of manufacture included hard-hammer percussion, or detaching flakes from cores with a stone hammer; the anvil technique, striking a core on a stationary anvil to detach flakes; and bipolar technique, detaching flakes by placing the core between an anvil and the hammerstone.
 Early humans probably also made tools from a wide range of materials other than stone. For example, they probably used wood for simple digging sticks, spears, clubs, or probes, and they probably used shell, hide, bark, or horn to fashion containers. Unfortunately, organic materials such as these do not normally survive from earlier Stone Age times, so archaeologists can only speculate about whether such tools were used.
 Two of the oldest Oldowan sites are in Ethiopia: Gona (occupied 2.5 million years ago) and Omo (2.3 million years ago). Other well-studied Oldowan sites include Lokalalei (2.3 million years ago) and Koobi Fora (1.9 million to 1.4 million years ago), in Kenya; Olduvai Gorge (1.9 million to 1.2 million years ago), in Tanzania; Ain Hanech (perhaps 1.7 million years ago), in Algeria.  The cave deposits at Sterkfontein and Swartkrans (estimated to be from 2.0 million to 1.5 million years ago), in South Africa.
 Theories about the intelligence and culture of prehistoric man are beginning to be drastically revised. Accumulated evidence now depicts European men living between 100,000 and 10,000 years ago as communal men who were skilled hunters and toolmakers, who had developed formal burial rites for members of their tribes and ritual burials for animals, who had some belief in an afterlife, who took excellent care of their sick and elderly, and who, in their heyday, carried around pocket-sized calendars of their own making.
 A ten-member international expedition, led by Ralph S. Solecki of Columbia University, found the bones of a dismembered deer ritually buried by Neanderthal men about 50,000 years ago. The bones of the deer's foot, jaw, and back, its shoulder blades, and the top of its skull were found buried 5 feet deep in the Nahr Ibrahim Cave, north of Beirut, Lebanon. The presence of the skull, the bed of stones on which the bones were placed, and the red-earth colouring of the bones, which was not native to the cave, indicated that a ritual known as hunters' magic was involved in the burial. Solecki interpreted the burial as an attempt "to ensure a successful hunt by the ceremonial treatment of one of the animals." Although evidence existed showing that bears were ritually treated by Neanderthal men, this was the first discovery of a lone deer buried in this manner.
 An American expedition, also led by Solecki, excavated a mountain cave near Shanidar in Iraqui Kurdistan and discovered evidence that Neanderthals practiced a form of religious burial suggesting a belief in an afterlife: at least one of the nine skeletons uncovered in the cave was buried with flowers. Also found in the cave was the skeleton of a man of about 40, comparable to a modern age of 80, who had been born with a deformed right arm. A Neanderthal doctor had skilfully amputated the arm above the elbow, and judging by his death at a ripe old age, the man was carefully cared for from his boyhood until he died as a result of a rockfall inside the cave, a common peril at that time.
 Recent paleontological examinations of skeletons suggest that the Neanderthals' stooped posture was the result of a vitamin D deficiency. Lack of sunlight during the Ice Age might have caused their upright posture to become deformed by rickets.
 In January it was revealed that a fairly sophisticated system of notation charting the phases of the moon was used throughout most of Europe during the last Ice Age, beginning about 34,000 years ago. Marks such as scratches and notches on pieces of bones, antlers, and stone, previously regarded as decorations, were shown to be representations of the lunar calendar. Alexander Marshack, a research associate at the Peabody Museum of Archaeology and Ethnology at Harvard University, began investigating the markings in 1964 and published the results of his study this year in France. The inscribed objects he studied represented all cultural levels from 34,000 to 10,000 years ago. All were pocket-sized, and as many as 24 tools were used to cut a single sequence, some covering a year or more. This system of notation seems to anticipate the development of a calendar, the concept of number, and the use of abstract symbols. It had been thought that such cognitive abilities developed only after the start of an agricultural society, less than 10,000 years ago.
 A tribe of about 24 people living a Stone Age way of life was found in the Tasaday Forest on the southern Philippines' Mindanao Island in July. Anthropologists speculate that the tribe has been cut off from the rest of the world for at least 400 years and maybe as much as 2,000 years.
 The tribe was first discovered five years ago by an official conducting a census survey. He described the finding a tribe of "jungle people so mysterious that they were known only as the bird who walks the forest like the wind." A long search led to the Tasaday. Interpreters at first had trouble understanding the tribe's language, which is related to Manubo, a native Filipino tongue in the Malayo-Polynesian family.
 As communication became easier, it was found that the tribe calls itself the Tasaday because "the man who owns the forest in which they live told their ancestors in a dream to call themselves Tasadays, after a mountain." When asked whether they had ever been off the island, the Tasadays replied that they did not know leaving was possible; in fact, it was found that they had never even seen the ocean. The Tasadays are monogamous in mating but communal in all other ways, have no leader, know no other tribe, have known no unfriendly people, and have never heard of fighting.
 The Tasadays do not cultivate food but never ventures far from their clearing; food is easily found in the lush vegetation of the forest in which they live. The staple of their diet is the pith of the wild palm. To supplement this, they catch tadpoles and small fish with their hands from the nearby streams. Monkey meat is considered a delicacy. After the monkey's hair is singed in a fire and cut away with bamboo blades sharpened by small stones, the meat is roasted.
 The group includes six families with 13 children, nine of whom are boys. All matters of mutual concern, such as food gathering, are decided in an open meeting.
 New information about the Mayan civilization, the most highly developed civilization in the New World before the arrival of the white man, was gained from the discovery of a 11-page codex fragment of a Mayan calendar book. (A codex is a manuscript copy of an ancient text.) The fragment is said to be part of a larger book about 20 pages long. The three other known codices were brought to Europe during the Spanish conquest but did not emerge as important historical material until the 1900's. The newly discovered codex is the first to be found in over a century.
 Composed of bark cloth, like the other three, the 11-page codex is expected to reveal "pictorial information on the Venus calendar and its influence on Mayan religion and astrology," according to Michael D. Coe, professor of anthropology at Yale University. The fragment dates to the late Mayan period, between 1400 and 1500. The new fragment reveals that the Mayans viewed all four phases of the Venus cycle as threatening. Previously, only the first phase was thought to have been considered sinister.
 All four cycles of Venus as seen from the earth were measured by Mayan priests, who calculated that each cycle took 584 days to be completed. Modern astronomers calculate 583.92 days for each complete cycle. The complete 20-page codex would have covered 65 Venus cycles.
 Coe believes the fragment to be authentic "because it is on bark cloth, [because of] the condition of the fragment, the fact that none of the pictorial material duplicates or imitates anything we know about the Venus calendar, and, lastly, because no forger could be clever enough to invent material displaying so much knowledge of Mayan life."
 Early Slavic tribes formed an organized state in the fourth to sixth centuries, about 500 years earlier than was believed, according to evidence reported in Tass, the Soviet press agency. Arkady Bugai, the Ukrainian archaeologist credited with the discovery, based his conclusion on radiocarbon dating of charred wood found in the remains of the so-called Serpentine Wall, a 500-mile complex of defensive earthenworks that once ringed the present site of Kiev, the Ukrainian capital. The charred wood used in the radiocarbon tests was from what is believed to be the remains of trees burned to clear ground for the wall. Bugai reasoned that a highly organized state was required to move the seven billion cubic feet of earth that made up the wall, which rises to a height of 30 to 35 feet and is 50 feet wide at its base.
 The Serpentine Wall, which enclosed a roughly triangular area, was assumed to have been built to defend the Kiev area from hostile tribes. Ukrainian scholars now believe that the area must have had a population of approximately one million people during the time of the construction. It was formerly believed that the first consolidation of Russian tribes occurred around the tenth century, during the rise of Kievan Russia.
 An expedition bent on disproving the theory that the American man came to North America by crossing a land bridge over what is now the Bering Strait began in September. Gene Savoy, the American explorer who is known for his 1964 discovery of the ruined Inca city of Vilcabamba in Peru, believes that American man originated in the jungles east of the Andes Mountains in South America, where he thinks advanced civilizations flourished as long ago as 1500 BC. The discovery of a new species of human ancestors and of fossils of the oldest human beings yet to be found in Europe dominated the news in anthropology in 1995.
 The discovery of fossils of a new species of human ancestors — Australopithecus anamensis - at sites near Lake Turkana in Kenya was announced in August. Anamensis, a small-brained upright walker resembling the famous Lucy skeleton (identified with the species’ Australopithecus afarensis), weighed about 110 pounds. The complete upper and lower jaws, a set of lower teeth, a skull fragment, the teeth of several individuals, and a shinbone were dated to between 4.1 million and 3.9 million years ago, according to Meave Leakey (wife of Richard Leakey), one of the lead researchers.
 Anamensis, the researchers indicated, may be directly ancestral to later afarensis (dated at 3.6 million years old). The shinbone is the oldest direct evidence yet discovered for upright, a bipedal locomotion (the ability to walk upright on two legs), a defining trait of humans. The earliest known evidence before this was the tracks (3.7 million years old) of three humanlike individuals, probably australopithecines, who strolled across a bed of fresh volcanic ash in what is now Laetoli, Tanzania.
 The relationship between anamensis (from anam, a native Kenyan term for "lake") and an even older species whose discovery was announced in 1994 was unclear. The older species, found in the Middle Awash region of Ethiopia, was first named Australopithecus ramidus. The genus name was later changed to Ardipithecus ("ground apes"). The teeth and scanty bone fragments of Ardipithecus ramidus were dated at 4.4 million years old.
 Fragmentary fossil remains of at least four humans thought to be intermediate between Homo erectus and archaic forms of The Homo sapiens, the later species to which all modern humans belong, were found in caves in Atapuerca in northern Spain, according to a report published in August. Dated as at least 780,000 years old by means of a Paleomagnetic dating technique, the stone tools and skeletal fragments - including some from an adolescent and some from a child - of skulls, hands, and feet represent the oldest humans yet discovered in Europe. The researchers who found the fossils said they could possibly be distant ancestors of the Neanderthals who appeared in Europe hundreds of thousands of years later.
 The Spanish fossils partly fill a gap in the history of human evolution and expansion around the world. Previously, the oldest human fossils found in Europe, dating back 500,000 years, belonged to Heidelberg man, a likely ancestor of the Neanderthals, found at the Mauer site in Germany near the French border. It is known, however, that descendants of the earliest humans had spread from Africa to Asia well more than a million years ago. Among reasons given by anthropologists for the late occupation of Europe by Homo is the harshness of Europe's Ice Age climate.
 Finds of Neanderthaloid skulls and skeletons continue to be reported from widely separated areas. Digging in a cave at Mount Circeo on the Tyrrhenian sea, 50 miles south of Rome, Italy, Alberto Carlo Blanc uncovered an almost perfectly preserved Neanderthal skull, perfect except for a fracture in the right temporal region. It is the third of this type found in Italy. The two skulls previously reported were found in 1929 and 1935 in the Sacopastore region, near Rome, but in not nearly so well preserved a condition as the present find. No other human bones were found here, but the skull was accompanied by fossilized bones of elephants, rhinoceri, and giant horses, all fractured, thus giving some evidence of the mode of life of Neanderthal man. Professor Sergio Sergi, of the Institute of Anthropology at the Royal University of Rome, who has studied this skull in detail believes it to be 70,000 to 80,000 years old. He concludes also that Neanderthal man walked almost as erect as modern man and not with head thrust forward as had hitherto been assumed.
 Another Neanderthal skeleton is reported to have been found in a cave in Middle Asia by A. P. Okladnikoff of the Anthropological Institute of Moscow University and the Leningrad Institute of Anthropology. The bones of the skeleton were badly shattered, but the jaw and teeth of the skull, it crushed at the back, were almost complete
 Hominids that were contemporary with Oldowan sites include two major lineages. One is the robust australopithecines (so called because their cheek teeth were larger than those of other australopithecines). These robust australopithecines - such as Australopithecus aethiopicus and Australopithecus boisei in East Africa, and Australopithecus robustus in South Africa - were bipedal and had small brains, large jaws, and large molars. The other lineage is made up of bipedal, larger-brained, and smaller-toothed early members of the genus Homo, such as an a Homo habilis, Homo rudolfensis, and early Homo erectus. The oldest fossils of A Homo erectus (sometimes called Homo ergaster) found in Africa dates back to about 1.85 million years ago. This species is characterized by an even larger brain and smaller teeth than earlier hominids and by a larger body size. (In 1984 anthropologists in Kenya found a nearly complete skeleton of an adolescent Homo erectus who would have been 1.8 m (6 ft) tall as an adult.)
 Experts do not know for certain that of these species were responsible for individual Oldowan sites. These species may have made and used Oldowan-style stone tools to varying degrees. However, anthropologists have long suspected that the larger-brained and smaller-toothed Homo was probably a more habitual toolmaker. It is likely that Homo erectus was responsible for many Oldowan sites more recent than 1.85 million years ago. In any case, by one million years ago, all these species but The Homo erectus had gone extinct, so researchers can be certain that at least the Homo’s lineage was involved in using and making stone tools. The Homo erectus appears to have moved out of Africa and into Eurasia sometime before one million years ago, although some anthropologists think this geographic spread of hominids may have occurred nearly two million years ago. The everyday life of Oldowan hominids is largely a matter of archaeological conjecture. Most sites in East Africa are found near lakes or along streams, suggesting that they preferred to live near water sources. Studies of rock sources suggest that Oldowan hominids sometimes transported stone several kilometres to the sites where stone artifacts are found. Well-preserved sites often have collections of stone artifacts and fragmented fossil animal bones associated together, often in dense concentrations of several thousand specimens. Scholars disagree regarding the nature of these sites. Some archaeologists interpret them as camps, home bases, or central foraging places, similar to those formed by modern hunter-gatherers during their daily activities. Others think that such sites represent scavenging stations where hominids were primarily involved in processing and consuming animal carcasses. Still others view these accumulations as stone caches where hominids collected stone in areas where such raw materials did not occur naturally.
 Fossil remains from some Oldowan sites suggest that Oldowan hominids used stone tools to process meat and marrow from animal carcasses, some weighing several hundred pounds. Although some archaeologists have argued that large game hunting may have occurred in the Oldowan, many Oldowan specialists believe these early Stone Age hominids likely obtained most of their meat from large animals primarily through scavenging. The early hominids may have hunted smaller animals opportunistically, however. Modern experiments have shown that sharp Oldowan flakes are especially useful for the processing of animal carcasses—for example, skinning, dismembering, and defleshing. The bulk of early hominid diet likely consisted of a variety of plant foods, such as berries, fruits, nuts, leaves, flowers, roots, and tubers, but there are little archaeological records of such perishable foodstuffs.
 The term Acheulean was first used by 19th-century French archaeologist Gabriel de Mortillet to refer to remnants of a prehistoric industry found near the town of Saint-Acheul in northern France. The distinguishing feature of this site is an abundance of stone hand axes, tools more sophisticated than those found at Oldowan sites. The term Acheulean is now used to refer to hand axe industries in Africa, the Near East, Europe, and Asia dating from 1.5 million years ago to 200,000 years ago and spanning human evolution from A Homo erectus to early archaic Homo sapiens.
 The characteristic Acheulean hand axe is a large, pointed or oval-shaped form. These hand axes were often made by striking a blank (a rough chunk of rock) from a larger stone and then shaping the blank by carefully removing flakes around its perimeter. Usually, both sides, or faces, of the blank were flaking, a process called bifacial flaking. Later Acheulean hand axes may have been produced by the soft-hammer technique, in which a softer hammer of stone, bone, or antler produced thinner, more carefully shaped forms. Other associated forms include cleavers, bifacial artifacts with a sharp, guillotine-like bit at one end; and thick, pointed artifacts known as picks. Simpler, typical Oldowan artifacts are usually also found at Acheulean sites, and a range of retouched flake tools such as scrapers. Experiments have demonstrated that Acheulean hand axes and cleavers are excellent tools for heavy-duty butchery activities, such as severing animal limbs. Some archaeologists, however, believe they may have served other functions, or perhaps were general, all-purpose tools.
 Acheulean tools did not entirely replace Oldowan tools. Archaeologists have discovered numerous sites where Oldowan tools were used throughout the Acheulean time, sometimes in the same geographic region as Acheulean industries. Interestingly, the Acheulean might be especially restricted to Africa, Europe, and western Asia, with few sites in East Asia of stone industries with typical Acheulean hand axes and cleavers during the Lower Paleolithic. Most of the industries found in East Asia tend to be simpler, Oldowan-like technologies that can be seen at sites at Nihewan and the cave of Zhoukoudian in northern China.
 Well-studied Acheulean sites include those at Olduvai Gorge and Isimila, in Tanzania; Olorgesailie, in Kenya; Konso Gardula and Melka Kunture, in Ethiopia; Kalambo Falls, in Zambia; Montagu Cave, in South Africa; Tabun and Gesher Benot Ya'aqov, in Israel; Abbeville and Saint-Acheul, in France; Swanscombe and Boxgrove, in England; and Torralba and Ambrona, in Spain.
 Most anthropologists think that Acheulean populations of The Homo erectus and early Homo sapiens were probably more efficient hunters than Oldowan hominids. Recently discovered wooden spears from about 400,000 years ago at Schöningen, Germany, and a 300,000-year-old wooden spear tip from Clacton, England, suggest that the hominids who made these implements may have hunted game extensively.
 Experts disagree about whether Acheulean hominids and their contemporaries harnessed the use of fire. Archaeologists have found evidence such as apparent burnt bone and stone, discoloured sediment, and the presence of charcoal or ash at most sites, including Cave of Hearths, in South Africa; Zhoukoudian, in China; and Terra Amata, in France. Discrete fireplaces (hearths), however, may be quite rare. Similarly, there is only questionable evidence of huts or other architectural features.
 The Middle Paleolithic extends from around 200,000 years ago until about 30,000 years ago. It is also called the Mousterian Industry in Europe, the Near East, and North Africa and called the Middle Stone Age in sub-Saharan Africa.
 Toolmakers in the Middle Paleolithic used a range of retouched flake tools, especially side-scrapers, serrated scrapers, backed knives (blade tools with the nonblade side dulled to fit comfortably in the hand), and points. Experts believe these tools were used to work animal hides, to shape wood implements, and as projectile points. This period is also characterized by specially prepared cores. Using the disc core method, a circular core could produce numerous flakes to serve as blanks for retouched tools. With the Levallois method (named after a suburb of Paris, France, where the first such artifacts were discovered), flakes of a predetermined shape were removed from specially prepared cores. This process resulted in oval-shaped flakes or large, triangular points, depending on the type of Levallois core. Levallois core and flakes are first seen at some late Acheulean sites but become much more common in the Middle Paleolithic/Middle Stone Age.
 Some regional variation can be seen among Middle Paleolithic industries. A North African variant known as Aterian produced tools and point characterized by tangs (stems projecting from the base of the tool or point, to allow the tool to be attached to a handle or shaft). In Eastern Europe, a variant called Szeletian produced two-sided, leaf-shaped points, a style not usually seen elsewhere until the Upper Paleolithic. In Central Africa, a variant called the Sangoan produced a range of heavy-duty picks and axes.
 Middle Paleolithic/Middle Stone Age archaeological sites are often found in the deposits of caves and rock shelters. Well-studied caves include Pech de l'Aze, Combe Grenal, La Ferrassie, La Quina, and Combe Capelle, in France; Tabun, Kebara, Qafzeh, and Skhul, in Israel; Shanidar, in Iraq; Haua Fteah, in Libya; and Klasies River Mouth, in South Africa. In East Asia, sites that are contemporary with the Middle Paleolithic often exhibit a simpler toolmaking technology, without as much standardization of the flake tool forms as in much of the rest of Eurasia and Africa.
 Hominids associated with the Middle Paleolithic include Neanderthals and other archaic Homo sapiens (Homo sapiens predating anatomically modern humans, who lived from about 200,000 to 35,000 years ago). In Europe, the Middle Paleolithic is associated with Homo sapiens neanderthalensis, or Neanderthals, who lived from about 200,000 to 35,000 years ago. Neanderthals were short, robust humans with fully modern cranial capacity. They had more jutting faces, more prominent brow ridges, thicker cranial bones, and larger nose cavities than modern humans. Skeletal remains show that Neanderthals were very robust and muscular. Healed injuries to some skeletons suggest that Neanderthals led stressful, rigorous lives. Famous Neanderthal discoveries include Neander Valley, in Germany; La Chapelle-aux-Saints and La Ferrassie, in France; Krapina, in Croatia; Monte Circeo and Saccopastore, in Italy; Shanidar, in Iraq; and Tabun and Amud, in Israel. Fossils of an archaic Homo sapiens from this time have been found at sites such as Dali and Maba, in China and at Florisbad, in South Africa, and Ngaloba, in Tanzania. In addition, fossils interpreted as early anatomically modern humans have been found at some Middle Paleolithic/Middle Stone Age sites in parts of Africa and the Near East, such as at Qafzeh and Skhul, in Israel, and Klasies River Mouth, in South Africa.
 Middle Paleolithic hominids appear to have been more successful hunters than their predecessors. Abundant animal remains suggest that these hominids ate many kinds of large mammals. It is unknown, however, how much of the meat consumed was obtained through hunting, as opposed to scavenging. Accumulations of remains at some sites show that some animals were of a common species and were adults in their prime, which some researchers suggest is an indication of efficient hunting behaviour. Several sites in Europe that contain the carcass of one or more large animals are believed to be butchery sites, where early humans processed the spoils of kills. Some archaeologists have also argued that some Middle Paleolithic stone points were probably attached to spears, a development in hunting technology. At Klasies River Mouth Cave in South Africa, archaeologists discovered a buffalo vertebra with a broken tip of what was probably a spearhead embedded in it, which could be evidence that the large mammal was hunted or trapped by hominids.
 Middle Paleolithic hominids tend to show more behavioural complexity than their predecessors. For example, although most of the stone found at most Middle Paleolithic sites are local—its sources within a few kilometres of a site - an increasing percentage is exotic stone, transported from its sources tens of kilometres away. Simple hearths at many Middle Paleolithic sites suggest habitual fire use and possible firemaking as well. Evidence of housing is still quite uncommon, but is present at some sites. For example, at Molodovo, Ukraine, a circle of mammoth bones has been interpreted as a hut structure. Microscopic studies of residues on Middle Paleolithic scraper tools suggest that they may have been used for woodworking and to work animal hides for use as clothing or in shelters.
 Over the Middle Paleolithic, hominids spread across much of Eurasia. The use of fire and clothing and the ability to build more substantial shelters may have helped them survive in cold regions, such as the central Asian steppe. By 40,000 years ago, near the end of the Middle Paleolithic, humans entered Australia, which apparently would have required traversing some distance of open ocean, probably in some form of craft. Some Middle Paleolithic sites have skeletal remains interpreted as simple burials. No representational art is known from this period, although occasional ornaments such as beads have been found at late Middle Paleolithic/Middle Stone Age sites.
 Opinion is divided among anthropologists about whether Neanderthals and other archaic Homo sapiens had fully modern cognitive abilities, particularly the ability to recognize and communicate with symbols, a skill required to form modern languages. On one hand, the large cranial capacities of these populations might suggest modern human cognitive and behavioural capabilities. On the other hand, their technological development was very slow, and they left behind no trace of the use of symbols, such as representational cave paintings. Archaeologists have found much greater evidence of symbolism and cultural complexity during the Upper Paleolithic.
 The Upper Paleolithic extends from approximately 40,000 years ago until the end of the last ice age, about 10,000 years ago. This era is known as the Paleo - Indian period in the Americas, and as the Later Stone Age in a sub - Saharan Africa, where it extended much longer, even to historical times in parts of the continent. In the Upper Paleolithic, standardized blade industries appear and become much more widespread than in previous times. The first of these industries to appear in the Near East and Europe is known as Aurignacian. Later Upper Paleolithic industries include the Perigordian, Solutrean, and Magdalenian. The Upper Paleolithic is usually characterized by specially prepared cores from which blades (flakes at least twice as long as they are wide) were struck off with a bone or antler punch. Upper Paleolithic humans also developed new forms of scrapers, backed knives, burins, and points. Beautifully made, two - sided, leaf - shaped points are also common in some Upper Paleolithic industries. Toward the end of the Upper Paleolithic, microliths (small, geometric - shaped blade segments) became increasingly common in many areas.
 By the end of the Upper Paleolithic period and the end of the last ice age about 10,000 years ago, human populations had spread to every continent except Antarctica. Humans had effectively adapted to the northern latitudes of Eurasia and had dispersed into the American continents. The earliest well - documented occupation of the Americas appears to have been during the late ice age, about 12,000 to 10,000 years ago. The first recognized Paleo - Indian industry is known as Clovis, which was followed by Folsom. These industries produced delicately crafted, bifacial points fluted, meaning that the base of the point is thinned by removing a large flake from one or both sides. Fluted Clovis points have been found at mammoth kill sites, while Folsom points are associated with bison kills, mammoths being extinct by that time.
 Famous Upper Paleolithic occupation sites include Laugerie Haute, La Madeleine, Abri Pataud, and Pincevent, in France; Castillo, Altamira, and El Juyo, in Spain; Dolní Vestonice, in the Czech Republic; Mezhirich, in Ukraine; Sungir and Kostenki, in Russia; Ksar Akil, in Lebanon; Kebara, in Israel; Zhoukoudian Upper Cave, in China; Haua Fteah, in Libya; and Taforalt, in Morocco. Well - known Later Stone Age sites in sub - Saharan Africa includes Lukenya Hill, in Kenya; Kalemba, in Zambia; and Rose Cottage Cave, Wilton Cave, Nelson Bay Cave, and Boomplaas in South Africa. The most famous Paleo - Indian sites are those moved to the United States near the eastern New Mexico towns of Clovis and Folsom, which gave the industries their names.
 Human fossils associated with the Upper Paleolithic, Paleo - Indian, and Later Stone Age are usually those of anatomically modern humans, or The Homo sapiens. In the 19th century, Homo sapiens skeletal remains were found associated with early Upper Paleolithic artifacts at the rock shelter of Cro - Magnon in southern France. The term Cro - Magnon Man has thus sometimes been used to refer to anatomically modern humans from the Upper Paleolithic. Not all humans were anatomically modern in this period, however. In the early stages of the Upper Paleolithic, the sites that make up the Chatelperronian industry are associated with late Neanderthals, possibly influenced by modern humans arriving with Aurignacian technology.
 During the Upper Paleolithic, tools of bone, antler, and ivory become common for the first time. These tools include points, barbed harpoons, spear throwers, awls, needles, and tools interpreted as spears - shaft straighteners. The presence of eyed needles indicates the use of sewn clothing (presumably of hide and possibly early textiles) or hide coverings for tents or shelters. In some carvings from this period, human figures are depicted wearing hooded parkas or other vestments. Other technological innovations include lamps (in hollowed out stones filled with flammable substances such as oil or animal fat) and probably the bow and arrow (small projectile points have been interpreted as arrowheads). Many Upper Paleolithic artifacts might be evidence of composite technology, in which multiple components were combined to form one tool or process. For example, spear tips were attached with binding material to spear shafts, which were flung using spear throwers (sometimes called atlatls). A spear thrower usually took the form of a length of wood or bone with a handle on one end and a peg or socket at the other to hold the butt of a spear or dart. When swung overhand together, the spear thrower provided greater thrust on the spear.
 Upper Paleolithic populations appear to have been competent-hunter -gatherers. The use of mechanical devices such as spear throwers and, probably, arm bows and an arrowed weapon allowed them to increase the velocity, penetrating force, and distance of projectiles. Many Upper Paleolithic sites contain large quantities of mammal bones, often with one species predominating, such as red deer, reindeer, or horse. It is believed that many of these Upper Paleolithic hunter-gatherers could effectively predict the timing and location of seasonal resources, such as reindeer migrations or salmon runs.
 Many Upper Paleolithic sites feature elements interpreted as evidence of housing. These are commonly patterns of bone or stone concentrations that seem to delineate hut or tent structures. At the sites of Étiolles and Pincevent, in France, the distribution of stone artifacts, animal bones, hearths, and postholes has been interpreted as evidence of clearly defined huts. At Mezhirich, in the Ukraine, and Kostenki, in Russia, hut structures were found made of stacked or aligned mammoth bones. Distinctive hearths, often lined or ringed with rocks, is much more common in the Upper Paleolithic than in earlier times.
 Stone for tools was often obtained from more distant sources, sometimes in larger quantities than seen previously in the Stone Age. Occasionally, stone was traded or carried over several hundred kilometres. It seems likely, therefore, that trade and transport routes were more formalized than they had been in earlier times. The Upper Paleolithic also documents the trade of exotic materials - such as marine shells or semiprecious stones—for personal ornamentation as beads or on necklaces.
 In the Upper Paleolithic, evidence of human burial is much more common. In addition, burials tend to be more elaborate than in Neanderthal times, often associated with rich grave goods. For example, at Sungir, in Russia, three individuals were buried with ivory spears, pendants and necklaces of shells and animal teeth, and thousands of ivory beads that had apparently been sewn into their clothing.
 The earliest representational art—in the form of painting, sculpture, and engraving—dates back to approximately 32,000 years ago. Sites in Europe are famous for their artwork, but prehistoric Stone Age art has also been richly documented in Africa, Australia, and other parts of the world. Animals are common subjects of Upper Paleolithic art, and human figures and abstract elements such as lines, dots, chevrons, and other geometric designs are also found.
 Early humans around the world used natural materials such as red and yellow ochre, manganese, and charcoal to create cave art. Among the hundreds of European sites with Upper Paleolithic cave paintings, some best known are Altamira, in Spain, and Lascaux and the more recently discovered (and archaeologically oldest) Chauvet, in France. Animals such as bison, wild cattle, horses, deer, mammoths, and woolly rhinoceroses are represented in European Upper Paleolithic cave art, with human figures relatively uncommon. Later Stone Age paintings of animals have been found at sites such as in Apollo 11 Cave, in Namibia; and stylized engravings and paintings of circles, animal tracks, and meandering patterns have been found in Australia’s Koonalda Cave and Early Man Shelter.
 Many small sculptures of human female forms (often called Venus figurines) have been found in numerous sites in Europe and Asia. Small, stylized ivory animal figures made more than 30,000 years ago were discovered in Vogelherd, Germany, and clay sculptures of bison were found in Le Tuc d̀Audoubert, in the French Pyrenees. In addition, many utilitarian objects—such as spear throwers and batons—were superbly decorated with engravings, sculptures of animals, and other motifs.
 The earliest known musical instruments also come from the Upper Paleolithic. Flutes made from long bones and whistles made from deer foot bones have been found at a number of sites. Some experts believe that Upper Paleolithic people may have used large bones or drums with skin heads as percussion instruments.
 The archaeological record of the Upper Paleolithic shows a creative explosion of new technological, artistic, and symbolic innovations. There is little doubt that these populations were essentially modern in their biology and cognitive abilities and had fully developed language capabilities. There is a much greater degree of stylistic variation geographically (Some archaeologists have suggested that this be evidence of the emergence of ethnicity) and a more rapid developmental pace during the Upper Paleolithic than in any previous archaeological period. Anthropologists hotly debate whether these new Upper Paleolithic patterns are due to biological transition or whether they are simply the products of accumulated cultural knowledge and complexity through time.
 The Mesolithic (also known as the Epipaleolithic) extends from the end of the Pleistocene Ice Age, about 10,000 years ago, until the period when farming became central to a peoples’ livelihood, which occurred at different times around the world. The term Mesolithic is generally applied to the period of post - Pleistocene hunting and gathering in Europe and, sometimes, parts of Africa and Asia. In the Americas, the post - glacial hunters - a gatherer stage that predates the dominance of agriculture is usually called the Archaic. In the rest of the world, Mesolithic sites are usually characterized by microliths. Microlithic blade segments were commonly retouched into a range of shapes, including crescents, triangles, rectangles, trapezoids, and rhomboids, and thus the tools are often called geometric microliths. These forms often have multiple sharp edges. Many of these microliths probably served as elements of composite tools, such as barbed or a knife edge - tipped spears or arrows, or wooden - handled knives. The microliths were likely inserted into shafts or handles of wood or antler and reinforced with some type of adhesive.
 The end of the ice age brought rapid environmental change in much of the world. With the warmer, post - glacial conditions of the Holocene Epoch, ice sheets retreated and sea levels rose, inundating coastal areas worldwide. Temperate forests spread in many parts of Europe and Asia. As these climatic and vegetative changes occurred, large herds of mammals, such as reindeer, were replaced by more solitary animals, such as a red deer, fish eggs, deer, and wild pig. Cold - adapted animals, such as the reindeer, elk, and bison, retreated to the north, while others, such as the mammoth, giant deer, and woolly rhinoceros, went extinct. The rich artistic traditions of Upper Paleolithic Western Europe declined markedly after the end of the ice age. This may in part be because the changing environment made the availability of food and other resources less predictable, requiring populations to spend more time searching for resources, leaving less time to maintain the artistic traditions.
 Well-studied Mesolithic/Archaic sites include Star Carr, in England; Mount Sandel, in Ireland; Skara Brae, in Britain’s Orkney Islands; Vedbæk, in Denmark; Lepenski Vir, in Serbia; Jericho, in the West Bank; Nittano, in Japan; Carrier Mills, in Illinois; and Gatecliff Rockshelter, in Nevada. In the sub - Saharan Africa, many Later Stone Age sites of the Holocene Epoch could broadly be termed Mesolithic, due to their geometric microliths and bow and arrow technology.
 During the Mesolithic, human populations in many areas began to exploit a much wider range of foodstuffs, a pattern of exploitation known as broad spectrum economy. Intensively exploited foods included wild cereals, seeds and nuts, fruits, small game, fish, shellfish, aquatic mammals and birds, tortoises, and invertebrates such as snails. Dogs were domesticated in this period, probably for use in hunting. Some Mesolithic hunter-gatherers, such as the Natufian of the Near East, appear to have lived in small settlements based on an economy involving gazelle hunting and the harvesting of wild cereals using sickles with flint blade segments inset in bone handles. In the Near East and North Africa, Mesolithic populations processed wild plant foods using grinding stones.
 Other Mesolithic technological innovations include the adz and axe (woodworking tools consisting of flaked stone blades set in bored antler sleeves and fastened to wooden handles), fishing weirs and traps, fishhooks, the first preserved bows and arrows, baskets, textiles, sickles, dugout canoes and paddles, sledges, and early skis. The Jomon culture of Japan produced pottery by 10,000 years ago, as did the Ertebølle culture of Scandinavia moderately later.
 The development of broad spectrum economies in the post-glacial Mesolithic/Archaic period laid the foundations for the domestication of plants and animals, which in turn led to the rise of farming communities in some parts of the world. This development marked the beginning of the Neolithic.
 Farming originated at different times in different places—as early as about 9,000 years ago in some parts of the world. In some regions, farming arose through indigenous developments, and in others it spread from other areas. Most archaeologists believe that the development of farming in the Neolithic was one of the most important and revolutionary innovations in the history of the human species. It allowed more permanent settlements, much larger and denser populations, the accumulation of surpluses and wealth, the development of more profound status and rank differences within populations, and the rise of specialized crafts.
 Neolithic Toolmaking generally shows an advanced portion of technological continuity with the Mesolithic, however, Neolithic industries often include blade and bladelet (small blades) technologies, and sometimes in the accompaniment with microliths. A vast horizon widened by a range-over of retouched tools, including endscrapers (narrower scrapers for working hides). Moreover, be in the back blades or bladelets (some of which were set into  handles and used as sickles), and a widen range of activated points. In addition, ground and polished axes and adzes—which would have been used for forest clearance to plant crops, and for woodworking activities—are characteristic of the Neolithic. Such tools, although labour-intensive to manufacture, has a tendency to last a long time without requiring resharpening and consequently were highly prized by these early farmers. Large-scale trade networks of axes and stone are documented in the Neolithic, with artifacts sometimes found hundreds of miles from their sources. Other technological developments in the Neolithic include grinding stones, such as mortars and pestles, for the processing of cereal foods, the widespread use of pottery for surplus food storage and cooking, the construction of granaries for storage of grains, the use of domesticated plant fibres for textiles, and weaving technology.
 Archaeologists have several theories to explain why humans began farming. The reasons probably differed moderately from one region to another. Some theories maintain that population pressure or changes in environment may have forced humans to find new economic strategies, which led to farming. Another theory maintains that a population of humans may have lived in a region where domesticating wild plants and animals was relatively easy, making the development of agriculture essentially a historical accident. Still another theory proposes that the rise of farming may have varied with social change, as individuals began to use agriculture as a means to acquire wealth as food surpluses.
 Different plant crops were cultivated in different places, depending on what wild plants grew naturally and how well they responded to cultivation. In the Near East, important crops included wheat, barley, rye, legumes, walnuts, pistachios, grapes, and olives. In China, millet and rice predominated. In Africa, millet, sorghum, African rice, and yams were commonly grown. Rice, plantains, bananas, coconuts, and yams were important in Southeast Asia. Finally, in the Americas, corn, squash, beans, potatoes, peppers, sunflowers, amaranths, and goose-foots were commonly grown.
 Domesticated animals also varied from one region to another according, again, to availability and their potential to be domesticated. In Eurasia, Neolithic people domesticated dogs, sheep, goats, cattle, pigs, chickens, ducks, and water buffalo. In the Americas, domesticated animals included dogs, turkeys, llamas, alpacas, and guinea pigs. In Africa, the primary domesticated animals - cattle, sheep, and goats - probably spread from the Near East.
 Well-studied early farming sites in Eurasia include Jericho, in the West Bank; Ain Ghazal, in Jordan; Ali Kosh, in Iran; Mehrgarh, in Pakistan; Banpocun (Pan-p’o-ts’un), in China; and Spirit Cave, in Thailand. Important African sites include Adrar Bous in Niger, Iwo Eleru in Nigeria, and Hyrax Hill and Lukenya Hill in Kenya. In the Americas, sites showing early plant domestication include Guila Naquitz, in Mexico, and Guitarrero Cave, in Peru.
 Larger Neolithic settlements show a variety of new architectural developments. For instance, in the Near East, conical beehive - shaped houses or rambling, connected apartments - style housing was often constructed with mud bricks. In Eastern Europe, houses were made with wattle and daub (interwoven twigs plastered with clay) walls, and, in later times, longhouses were constructed with massive timbers. In China, some settlements contain semisubterranean houses dug into clay, with evidence of walls and roofs made out of thatch or other materials and supported by poles.
 The domestication of plants and animals led to profound social change during the Neolithic. Surpluses of food, such as stored grain or herds of livestock, could become commodities of wealth for some individuals, leading to social differentiation within farming communities. Trade of raw materials and manufactured products between different areas increased markedly during the Neolithic, and many foreign or exotic goods appear to have developed special symbolic value or status. Some Neolithic graves contain rich stores of goods or exotic materials, revealing differentiations in terms of wealth, rank, or power
 In certain areas, notably parts of the Near East and Western Europe, Neolithic peoples erected massive ceremonial complexes, efforts that would have required extensive, dedicated work forces. Large earthworks and megalithic (“giant stone”) monuments from the Neolithic (including the Avebury stone circle and the earliest stages of Stonehenge, in England, and the monuments of Carnac, in France), suggest more highly organized political structures and more complex social organization than among most hunters - gatherer populations. In the Americas, sites such as the mounds of Cahokia, in Illinois, also indicate a more complex, organized political and social order. The technological innovations and economic basis established and spread by Neolithic communities ultimately set the stage for the development of complex societies and civilizations around the world.
 Humans produced metal tools and ornaments from beaten copper as early as 12,000 years ago in some parts of the world. By 6,000 years ago, early experiments in metallurgy, particularly extracting metals from copper ore (smelting), were being conducted in some parts of Eurasia, notably in Eastern Europe and the Near East. By 5,000 years ago, copper and tin ores were being smelted and alloyed in some regions, marking the dawn of the Bronze Age. Casting of bronze tools - such as axes, knives, swords, spearheads, and arrowheads - became increasingly common over time. At first, copper and bronze tools were rare and stone tools were still very common, but as time went on, metal tools gradually replaced stone as the principal raw material for edged tools and weapons.
 In Eurasia and parts of Africa, the rise of metallurgical societies appears to coincide with the rise of the earliest state societies and civilizations, such as ancient Egypt, Sumer, Minoan Culture, Mycenae, and China. In the Americas, parts of sub-Saharan Africa, Australia, and the Pacific Islands, societies continued to use stone and other nonmetal materials as the principal raw materials for tools up to the time of European contact, starting in the 15th century ad. Although, technically, populations in these areas could have been said to be Stone Age groups, many had become agricultural societies and had formed flourishing civilizations.
 Stone technology enjoyed a brief resurgence within iron-using societies with the advent of flintlock firearms, beginning in the 17th century. Carefully shaped flints—reminiscent of the geometric microliths of the Mesolithic and early Neolithic-were struck against steel to create a spark to ignite the firearm. By the end of the 20th century few human groups had a traditional stone technology, although a few groups on the island of New Guinea still relied on the use of stone adzes. Tools of metal, plastic, and other materials had replaced stone technologies virtually everywhere.
 Cave Dwellers, is the term used to designate an ancient people who occupied caves in various parts of the world. Cave dwellers’ date generally from the Stone Age period known as the Paleolithic, which began as early as 2.5 million years ago. Caves are natural shelters, offering shade and protection from wind, rain, and snow. As archaeological sites, caves are easy to locate and often provide conditions that encourage the preservation of normally perishable materials, such as bone. As a result, the archaeological exploration of caves has contributed significantly to the reconstruction of the human past.
 Cave Painting, of Lascaux, France where some Palaeolithic artists painted scenes in caves more than 15,000 years ago, such as the one here found in Lascaux, France. The leaping cow and group of small horses were painted with red and yellow ochre that were either blown through reeds onto the wall or mixed with animal fat and applied with reeds or thistles. It is believed that prehistoric hunters made these paintings to gain magical powers that would ensure a successful hunt.
 Wherever caves were available, prehistoric nomadic hunters and gatherers incorporated them into the yearly cycle of seasonal camps. Most of their activities took place around campfires at the cave mouth, and some caves contain stone walls and pavements providing additional protection from winds and dampness. Hunting, particularly of reindeer, horse, red deer, and bison, was important; many caves are situated on valley slopes providing views of animal migration routes.
 Stone Toolmaking Humans first made tools of stone at least 2.5 million years ago, initiating the so-called Stone Age. The Stone Age advanced through three stages over time - the Paleolithic (which is subdivided into Lower, Middle, and Upper periods), Mesolithic, and Neolithic. Blade toolmaking, as demonstrated in this video, was a development of the Upper Paleolithic, which began about 40,000 years ago. This technique produced a far greater variety and higher quality of tools than did earlier methods of toolmaking.
 Artifacts have been found in caves in France, Spain, Belgium, Germany, Italy, and Great Britain. The association of these remains with the bones of extinct animals, such as the cave bear and saber-toothed tiger, indicates the great antiquity of many cave deposits. A variety of stone and bone points discovered in excavated caves documents the importance of spears until the bow and arrow appeared in the late Paleolithic era. Other common tools included stone scrapers for working hides and wood, burins for engraving, and knives for butchering and cutting. Throughout the Paleolithic period such tools became increasingly diverse and well made. Bone needles, barbed harpoons, and spear-throwers were made and decorated with carved designs. Evidence of bone pendants and shell necklaces also exists. Among the caves that have yielded relics of early humans are the Cro-Magnon and Vallonnet in France.
 Wall paintings and engravings have been found in more than 200 caves, largely in Spain and France, dating from 25,000 to 10,000 years ago. Frequently found deep inside the caves, and the paintings depict animals, geometric signs, and occasional human figures. In the cave of La Colombière in France, a remarkable series of sketches engraved on bone and smoothed stones was unearthed in 1913. In caves such as Altamira in Spain and Lascaux in France, multicolored animal figures were drawn using mineral pigments mixed with animal fats. Some paintings adorn walls of large chambers suitable for ritual gatherings; others are found in narrow passages accessible only to individuals. Hunting and fertility seems to have been important artistic themes. The ritual gatherings themselves promoted communication and intermarriage among the normally scattered small groups. Chinese caves contain some earliest evidence of human use of fire
 On every continent, prehistoric foragers used caves. In the Zhoukoudian (Chou-k'ou-tien) Cave near Beijing, China, remains of bones and tools of A Homo erectus (Peking Man) have been discovered. Chinese caves contain some earliest evidence of human use of fire, approximately 400,000 years ago. In the Shânîdâr Cave in Iraq, 50,000-year-old Neanderthal skeletons were unearthed in 1957. Ancient pollen buried with them has been interpreted as evidence that these cave dwellers had developed funeral rituals. In the western deserts of North America, caves have been located that contain plant foods, woven sandals, and baskets, representing the desert culture of a belated 9000 years ago. Early inhabitants of Australia, the Middle East, and the Peruvian Andes have also left remains in caves.
 Gradually people learned to grow food, rather than forage for it. This was the beginning of the Neolithic age, which, although ending in western Europe some 4500 years ago, continued elsewhere in the world until modern times. Once agriculture became important, people established villages of permanent houses and found new uses for caves, mainly as hunting and herding campsites and for ceremonial activities. In Europe, Asia, and Africa caves continued to be used as shelters by nomadic groups.
 Cave Dwellings These cave dwellings are located in the Cappadocia region of Central Anatolia Göreme, Turkey. Known as ”fairy chimneys,“ they were carved into soft volcanic rock by anchorite (hermitic) Christian monks in the 4th century AD. Many of these dwellings are still occupied by Göreme Turks, who consider them to be healthy and inexpensive places to live Arcaid/Nick Meers
 In dry caves, preservation is often excellent, due to moistureless air and limited bacterial activity. Organic remains such as charred wood, nutshells, plant fibres, and bones are sometimes found intact. In wet caves, artifacts and other remains are often found encrusted with, or buried beneath, calcareous deposits of dripstone. The collected evidence of human habitation on the cave floor was often buried under rockfalls from the ceilings of caverns. Intentional burials have also been found in several cave sites.
 Because of the unusual preservative nature of caves and the great age of many remains found in them, the fallacious belief has arisen that a race of cave people existed. Most cave sites represent small, seasonal camps. Because prehistoric people spend a copious measurement of the year in open-air camps, the caves contain the remains of only part of a group’s total activities. Also, the cultural remains outside caves were subject to greater decay. Thus, the archaeological record of remote times is better seen in cave deposits.
 Caves have been systematically excavated during the past one hundred years. Since they often contain the remains of repeated occupations, caves can document changing cultures. For example, the economic transition from food collecting to agriculture is demonstrated by finds in highland Mexico and in Southeast Asia. Some caves in the Old World continued to be inhabited even after the close of the Stone Age; relics from the Bronze and Iron ages have been found in cave deposits. On occasion, material dating from the time of the Roman Empire has been recovered. The famous Dead Sea Scrolls, discovered in 1947, were preserved in caves.
 In 1935 Doctor F. Kohl-Larsen discovered fragments of two skulls in the gravels at the northeast end of Lake Eyassi, Tanganyika Territory, Africa, in association with fossilized bones of antelopes, pigs, and hyenas resembling types of animals now living in that area. The two hundred fragments of the skulls have been painstakingly assembled by Doctor Hans Weinert of Kiel, Germany, so that there are now available for study the skull cap of one individual and part of the face of another. Though critical study of these East African finds is still far from completion, their closest resemblance may be to Pithecanthropus erectus, the famous Java ape man. These remains have been tentatively dated as 100,000 years ago.
 Doctor Robert Broom of the Transvaal Museum, Pretoria, has continued his study of the human-like ape remains found in South Africa. He believes the Australopithecus skulls to be the most definitely ape-like, except their teeth, which show a closer similarity to those of man than of the gorilla or chimpanzee, and therefore that they are not actual ancestors of man, but rather, survivors of a possible ape-like ancestral stock that existed before Ice Age times.
 The distal end of a humerus, the proximal ends of an ulna, and the distal phalanx of a toe of Paranthropus robustus, and the distal ends of a femur of Plesianthropus were excavated in the Pleistocene bone breccia of Kromdrai, near Krugersdorp, South Africa, under the direction of Doctor Broom, thus suggesting that this early type of ape-man walked erect, and making a distinct departure from previous assumptions as to posture of this species.
 Professor Raymond Dart of Witwatersrand University (South Africa), the discoverer of the controversial Taungs skull (Australopithecus africanus) states that a high culture existed in the present habitat of the Bantu-speaking peoples of South Africa in the Late Stone Age before their advent in that part of Africa. Skeletons associated with the Mapungobwa finds appear to indicate that the civilization cantering to this place was associated with a race said to be intermediate between, and possibly a hybrid of, Cro-Magnon and Neanderthal types, which as known in Europe, are distinct races
  Finds of Neanderthaloid skulls and skeletons continue to be reported from widely separated areas. Digging in a cave at Mount Circeo on the Tyrrhenian sea, 50 miles south of Rome, Italy, Alberto Carlo Blanc uncovered an almost perfectly preserved Neanderthal skull, perfect except a fracture in the right temporal region. It is the third of this type found in Italy. The two skulls previously reported were found in 1929 and 1935 in the Sacopastore region, near Rome, but in not nearly so well preserved a condition as the present find. No other human bones were found here, but the skull was accompanied by fossilized bones of elephants, rhinoceri, and giant horses, all fractured, thus giving some evidence of the mode of life of Neanderthal man. Professor Sergio Sergi, of the Institute of Anthropology at the Royal University of Rome, who has studied this skull in detail believes it to be 70,000 to 80,000 years old. He concludes also that Neanderthal man walked almost as erect as modern man and not with head thrust forward as had hitherto been assumed.
 Another Neanderthal skeleton is reported to have been found in a cave in Middle Asia by A. P. Okladnikoff of the Anthropological Institute of Moscow University and the Leningrad Institute of Anthropology. The bones of the skeleton were badly shattered, but the jaw and teeth of the skull, such as for themselves were crushed at the back, were almost complete.
 The famous Chokoutien site near Peking, China, the home of ancient Peking man (Sinanthropus) previously reported, now proves also to have yielded additional more modern type skeletons studied by Doctor Franz Weidenreich and Doctor W. C. Pei, the leaders in research at this site. In the portion of the site known as the upper cave were found the remains of a relatively advanced culture suggesting a resemblance to the Late or Upper Paleolithic in Europe, thus implying an age of 100,000 to 200,000 years. These cultural remains were accompanied by skeletons of bear, hyena, and ostrich, long extinct forms, and tiger and leopard that longs since disappeared from this part of Asia. The three human skulls in condition good enough for detailed study indicate that they probably belong to three different racial groups. Of the two female skulls studied, one bears close resemblance to the skulls of modern Melanesians, with frontal deformation; the second to Eskimo skulls. The brain case of the male skull is in some respects very primitive, almost in the Neanderthaloid stage, but in other features is reminiscent of Upper Paleolithic Man. The face, is similar to, though not identical with, recent Mongolians. From this evidence it seems that racial mixture is no product of modern times, but has its roots in extreme antiquity. It should be noted also that though Mongolian types resembling the modern population of North China were not found in the upper cave, it does not necessarily mean that they were nonexistent during that period. It has been suggested that the population represented in the upper cave may have been a migrating group. Historic and prehistoric American Indian skulls resembling Melanesian, Eskimo, or more primitive types have been reported from time to time in America, so that it would appear from the present finds at Chokoutien that long before migrations from Asia to America are assumed to have taken place, types similar to those composing the native American populations were living permanently, or at least moving around in Eastern Asia
 In America, the search for additional evidence of Folsom Man continues. Near Fort Collins, Colorado, Doctor Frank H. H. Roberts, Jr., continued excavation at a camp site, uncovering a variety of tools and weapons, and the first known decorated objects from any Folsom site, two decorated beads. This earliest American. Folsom Man, may have lived contemporaneously with Old World Cro-Magnon Man, or some 25,000 years ago. This tentative date was assigned recently by Doctors Kirk Bryan and Louis L. Ray of Harvard University based on studies made at the Folsom camp site, known as the Lindenmeier site, in northeastern Colorado. Many stone points, identified as typically Folsom were found in an earth stratum above the floor of an ancient valley that is traceable to a terrace on a local stream. The terrace has been dated as of the late Ice Age. The dating is based on the assumed correlation between this late Ice Age stage with the Mankato of the Middle West and the Pomeranian of Europe. From this it appears that the culture-bearing layer of the Lindenmeier site was developed at the end of the glacial advance, or 25,000 years ago.
 An attempt has been made to adapt the method of dating ruins by analysis of tree rings, so successfully carried out in America, specifically in Southwestern United States, to Viking ruins in Southern Norway. E. de Geer, who has been carrying on this work, reports, that, from a study of the remaining timbers in a wooden burial chamber in a Viking mound, it was constructed in 931 ad. A Swedish fort in Gotland was found by the same method to have been built in five Ad.
 The Homo habilis, is an extinct primate classified in the subfamily Homininae, a group that includes humans. Scientists believe this species lived in Africa between two million and 1.5 million years ago. H. habilis are the earliest known member of the genus Homo, the branch of Hominines believed to have evolved into modern humans. The term Homo habilis means handy man, a name selected for the deposits of primitive tools found near H. habilis see fossils.
 Scientists distinguish H. habilis from australopithecines, the more primitive Hominines from which it evolved, by analysing key physical characteristics. H. habilis had a larger brain than australopithecines. The braincase of H. habilis measured at least 600 cubic centimetres
(37 cu inches) compared with the 500 cu cm (31 cu in) typical of australopithecines. Australopithecines had long arms and short legs, similar to the limbs of apes. The overall body form of australopithecines was also apelike in having large body bulk relative to its height. Proportionally, H. habilis resembled modern humans with its limbs and small body bulk relative to its height. H. habilis had smaller cheek teeth (molars) and a less protruding face than earlier Hominines. H. habilis were taller than australopithecines, but shorter than Homo erectus, a later, more humanlike species.
 The use of primitive tools implies that H. habilis had developed a different way of gathering food than earlier Hominines, which fed only on vegetation. H. habilis probably ate meat plus fruits and vegetables. Anthropologists disagree on whether H.habilis obtained this meat through hunting, scavenging, or a combination of both techniques
 British-Kenyan anthropologist Louis Leakey discovered the first fossil evidence of H. habilis at Olduvai Gorge in northern Tanzania in 1960. Other anthropologists have since discovered specimens in northern Kenya, South Africa, and Malawi. Although all these specimens had a larger brain than australopithecines, some had especially large brains (almost 800 cu cm or 49 cu in) and more modern skeletons. However, their large and slightly protruding faces seem more primitive than those of other H. habilis specimens. Most scientists now believe that these fossils represent a distinct species named Homo rudolfensis. Scientists debate over which of these two species evolved into the later, even larger-brained H. erectus. Many consider H.rudolfensis the more likely candidate because of its large brain and more modern skeleton. For anthropology, the science of man, 1964 was an eventful and exciting year. Perhaps the most important development of 1964 was the discovery in Africa of a new humanlike, tool-using species, possibly a direct ancestor of man. This was not the only remarkable thing. The new species, named Homo habilis, was very old, probably 1.75 million years old, which makes him nearly twice as old as any previously known tool-using animal. The appearance of Homo habilis on the scene caused great excitement between paleontologists and physical anthropologists and has led many of them to a major reconsideration of much of man's biological history
 The new discovery, like so many other important finds of recent years, was made by the top fossil finder of the 20th century, Louis S. B. Leakey, curator of the Coryndon Museum Centre for Prehistory and Paleontology, Nairobi, Kenya. Professor Leakey's work is invariably done with his wife.  Mary, a geologist, and their three sons, who have also recovered important fossil materials. The finds were made in the incredibly fossil-rich Olduvai Gorge, an arid chasm in the Serengeti Desert of mainland Tanzania (formerly Tanganyika). The section of Olduvai Gorge excavated by the Leakeys is the most spectacular single prehistoric site in the world. The gorge cuts directly through four main stratigraphic levels, or beds, and in these four beds there are undisturbed paleontological and archaeological deposits covering a time span of nearly two million years. The gorge contains the stratified records of the development of stone tools from the most simple beginnings to elaborately fashioned hand axes; it contains fossil evidence of four major types of men or near-men; and it is rich in fossil remains of ancient fauna, including insects, fish, reptiles, birds, and mammals of the lower and middle Pleistocene periods.
 The Homo habilis excavations were announced by Dr. Leakey at the National Geographic Society in Washington, D.C., and in the Apr. 4, 1964, issue of Nature. The Olduvai fossil remains are being studied by Professor Phillip Tobias, University of Witwatersrand, Johannesburg, and Dr. John R. Napier, Royal Free Hospital School of Medicine, London.
 The Leakeys found bones and teeth representing 16 hominid individuals in beds’ I and II (the two lowest beds) of Olduvai Gorge. One of these was the well-known Zinjanthropus, which is placed roughly in the genus Australopithecus. The australopithecines were a genus of near-men living about one million years ago, perhaps a little earlier. They were originally considered close to the direct line of man's ancestry, but this is now in doubt. All of the other finds are considered by Leakey, Tobias, and Napier to represent Homo habilis, a more advanced hominid with a size and shape intermediate between Australopithecus and Homo, the genus that includes modern man and his immediate ancestors of the past 500,000 years. The specific name habilis are from the Latin and means "able, handy, mentally skillful, vigorous."
 Not all of the 206 bones making a complete skeleton of Homo habilis have yet been discovered. The recovered parts, however, are numerous enough to give a good picture of his anatomy and, by inference, of his behaviour. The recovered parts include the remains of two or three skulls, three mandibles (jawbones), about 40 teeth, parts of a hand and foot, the bones of a lower leg, a collarbone, and some rib fragments.
 Some features distinguishing modern man from his ancestors of earlier epochs include legs and feet adapted for upright posture and bipedal gait; hands adapted for tool use rather than locomotion; teeth and jaws adapted for an omnivorous rather than a purely herbivorous diet; a brain adapted for good hand-eye coordination in tool manufacture and use; and the ability to communicate with language of the human sort. Except language, the foot, hands, jaws, teeth, and brain case of Homo habilis indicate his close relatives crossed the line between the prehumans and human grades.
 The fossil foot is nearly complete, lacking only the back part of the heel and the toes. The foot bones are within the range of variation of Homo sapiens. The large toe is stout and carried parallel to the other toes; the longitudinal and transverse arch system is like ours. The bones of the foot and leg show the adult Homo habilis had an upright posture and bipedal locomotion, a slender body build, and a stature of about four feet.
 The hands are not entirely apelike, nor are they typically human. The hand bones are heavier than ours, and the finger bones are curved inward. The tips of the fingers and thumb are broad, stout, and covered by flat nails, as our modern man's. Probably Homo habilis could not oppose his thumb and fingertips in the precision, pen-holding grip of modern man, but his hand can make stone tools.
 The jaws are smaller than those of Australopithecus; the front of the lower jaw is retreating, with no development of an external bony chin. The incisor teeth are relatively large, the canines are large relative to the premolars, and the premolars and molars are narrow in the tongue-to-cheek dimension. Both the manlike proportions of the teeth and the remains of fish, reptiles, birds, and small mammals found in his living sites show that Homo habilis had an omnivorous diet.
 The skull is intermediate in shape between Australopithecus and modern man. The mass of the facial relative to the cranial part of the skull is reduced and is thus more like the advanced forms. The greatest breadth of the skull is high on the vault. The curvature of the parietal bones is intermediate; that of the occipital bone resembles Homo sapiens.
 The brain case of the Olduvai specimen known as No. 7 has an estimated endocranial volume of 680 cc. The endocranial volume for australopithecines ranges from 435 to 600 cc., that of pithecanthropines from 775 to 1,225 cc., and that of modern man from about 1,000 to 2,000 cc., with an average of about 1,350 cc. Thus, the brain of Homo habilis, although both absolutely and relatively larger than any of the australopithecines, were not large, either absolutely or relatively, contrasted with that of modern man. A typical adult Homo habilis had a body weight of about 75 pounds and a brain weight of a little more than one pound, whereas a modern man of 150 pounds has a brain weight of about 3 pounds. In the period following Homo habilis, hominid body weight doubled, but the weight of the brain tripled.
 The stone tools found in association with Homo habilis are typical of the Oldowan industry first recognized by Leakey 30 years ago. Similar tools are found elsewhere in East Africa, and in South Africa, Angola, and North Africa. These tools are commonly called pebble tools because most of them are made from waterworn pebbles. Most of the Oldowan choppers are worked on both faces to produce a sharp but irregular cutting edge.
 These rough choppers made from potato-sized pieces of stone are the earliest known stone tools; they date from the very beginning of the Pleistocene. There is abundant evidence from Olduvai Gorge showing that the great hand ax or Chelles-Acheul culture evolved directly from the Oldowan stone industry.
 Oldowan pebble tools and the skeletal remains of Homo habilis are associated in six sites. At some East and South African sites, pebble tools are also found in association with Australopithecus, but Homo habilis are, according to Professor Tobias, always associated with Oldowan tools, whereas Australopithecus is not. The evidence from the six sites certainly shows that early hominids regularly manufactured tools of a set design before they developed hands or brains like those of modern man.
 The age of Homo habilis is as new and unexpected as the fossils themselves. Before these new finds most anthropologists thought the earliest toolmakers lived less than one million years ago. The potassium-argon process of dating had more than doubled the age of known tool manufacture.
 The principle of the potassium-argon technique is simple. The radioactive isotope potassium 40 (K40) found in volcanic rock is known to disintegrate into calcium 40 and argon 40 (A40), an inert gas. The rate of transmutation is constant and very slow; one half the K40 atom changes to A40 atoms each 1.3 billion years. The phosphorus-containing mineral anorthoclase is found in the volcanic deposits of Olduvai Gorge. While the lava was in a molten state beneath the earth, no A40 accumulated in the mineral because the gas boiled away. After the lava erupted and cooled, however, nearly all newly formed A40 atoms were imprisoned in the crystalline structure of the anorthoclase. By removing the mineral at a low temperature and then heating it, scientists have succeeded in collecting the released A40 atoms to be counted in a mass spectrometer. Because no A40 was initially present and because the rate of accumulation is also known, this count gives an estimate of the age of the rock. Several samples give age estimates ranging from 1.57 to 1.89 million years, or an average of 1.75 for Bed I in Olduvai, where Homo habilis were found and where the first tools of hominid manufacture appear.
 Homo erectus is an extinct primate classified in the subfamily Homininae and the genus Homo, which include humans. Scientists learn about extinct species, such as Homo erectus, by studying fossils—petrified bones buried in sedimentary rock. Based on their analysis of these fossils, scientists believe that Homo erectus lived from about 1.8 million to 30,000 years ago. Until recently, Homo erectus was considered an evolutionary ancestor of modern humans, or Homo sapiens.
 The anatomical features of Homo erectus are more humanlike than those of earlier Hominines, such as australopithecines and Homo habilis. Homo erectus had a larger brain, measuring up to 1150 cc, and a rounder cranium - the portion of the skull that covers the brain - than earlier Hominines. Homo erectus was also taller, with a flatter face and smaller teeth. Large differences in body size between males and females, characteristic of earlier hominine species, are less evident in Homo erectus specimens.
 This larger brain and more modern body-enabled Homo erectus to do many things its hominine ancestors had never done. Homo erectus appears to have been the first hominine to venture beyond Africa. It was the first hominine capable of systematic hunting, the first to make anything resemble home bases (campsites), and the first to use fire. Evidence suggests that the childhood of Homo erectus was longer than that of earlier Hominines, providing an extended period in which to learn complex skills. These skills are reflected in the relatively sophisticated stone tools associated with Homo erectus fossils. Although still primitive compared with the tools made by early Homo sapiens, the tools made by Homo erectus are much more complex than the simple, small pebble tools of earlier Hominines. The most characteristic of these tools was a teardrop-shaped hand ax, known to archaeologists as an Acheulean ax.
 Scientific study of Homo erectus began in the late 19th century. Excited by Charles Darwin‘s theory of evolution and fossil discoveries in Europe, scientists began to search for the fossilized remains of “the unknown factor,” the evolutionary ancestor of both human beings and modern apes. In 1891 Dutch anthropologist Eugene Dubois travelled to Java, Indonesia, where he unearthed the top of a skull and a leg bone of an extinct hominine. Measurements of the skull indicated that the creature had possessed a large brain, measuring 850 cc, while the leg-bone anatomy suggested that it had walked upright. In recognition of these characteristics, Dubois named the species Pithecanthropus erectus, or “erect ape-man.”
 Canadian anthropologist Davidson Black found similar fossils in China in the late 1920s. Black named his discovery Sinanthropus pekinensis, or “Peking Man.” Later studies by Dutch scientist G. H. von Koenigswald and German scientist Franz Weidenreich showed that the fossils discovered by Dubois and Black came from the same species, which was eventually named Homo erectus.
 Since these earliest discoveries, Homo erectus fossils have been found in East Africa, South Africa, Ethiopia, and various parts of Asia. Kenyan fossil hunter Kamoya Kimeu discovered an almost complete Homo erectus skeleton, known as the Turkana boy, near Lake Turkana in northern Kenya in 1984. The oldest known specimen, dated at almost two million years old, also comes from northern Kenya. Recently developed dating methods have shown that Homo erectus also lived in Java almost two million years ago
 Scientific assumptions about Homo erectus have changed dramatically since the early 1990s. Anthropologists long assumed that the species spread from Africa to parts of Asia and Europe and that these dispersed populations gradually evolved into Homo sapiens, or modern humans. Most anthropologists now think it more likely that Homo sapiens originated from a small population in Africa within the past 200,000 years. According to this theory, descendants of this African population of Homo sapiens spread throughout the eastern hemisphere, replacing populations of more ancient Hominines, perhaps with limited interbreeding.
 Many anthropologists now believe that some Homo erectus specimens should be classified as a separate species named Homo ergaster. According to this view, Homo ergaster appeared first in East Africa and quickly spread into Asia, where it evolved into Homo erectus. Homo sapiens arose in Africa from a population descended from Homo ergaster. Until recently, Homo erectus was thought to have died out about 300,000 years ago. Recent studies of Homo erectus populations in Java suggest that they may have lived until as recently as 30,000 years ago, long after the evolution of modern humans.
 Anthropologists also debate whether Homo erectus used language. Some scientists argue that the brain size of Homo erectus, the shape of its vocal structures, and the complexity of its behaviour indicate that it had a capacity for spoken language far beyond the rudimentary vocalizations of apes. Other anthropologists reject this conclusion. They point out that the first evidence of artistic expression, a trait closely linked with language, appears only about 40,000 years ago. These skeptics also point to the primitive quality of the tools associated with Homo erectus. Some anatomical evidence also suggests that Homo erectus lacked language abilities. The spinal column of early Homo erectus was significantly narrower than that of modern humans. This anatomical characteristic implies that Homo erectus had fewer nerves to control the subtle movements of the rib cages that are required for the production of spoken language. This question may remain unanswered, because, unlike stone tools, spoken words never become part of the archaeological record.
 The skulls and teeth of early African populations of middle Homo differed subtly from those of later H. erectus populations from China and the island of Java in Indonesia. H. ergaster makes a better candidate for an ancestor of the modern human line because Asian H. erectus has some specialized features not seen in some later humans, including our own species. H. heidelbergensis has similarities to both H. erectus and the later species H. neanderthalensis, although it may have been a transitional species between middle Homo and the line to which modern humans belong.
 The Homo’s ergaster probably first evolved in Africa around two million years ago. This species had a rounded cranium with a brain size of between 700 and 850 cu cm (49 to 52 cu in), a prominent brow ridge, small teeth, and many other features that it shared with the later H. erectus. Many paleoanthropologists consider H. ergaster a good candidate for an ancestor of modern humans because it had several modern skull features, including relatively thin cranial bones. Most H. ergaster fossils come from the time range of 1.8 million to 1.5 million years ago.
 The most important fossil of this species yet found is a nearly complete skeleton of a young male from West Turkana, Kenya, which dates from about 1.55 million years ago. Scientists determined the sex of the skeleton from the shape of its pelvis. They also determined from patterns of tooth eruption and bone growth that the boy had died when he was between nine and 12 years old. The Turkana boy, as the skeleton is known, had elongated leg bones and arm, leg, and trunk proportion that essentially match those of a modern humans, in sharp contrast with the apelike proportions of H. habilis and Australopithecus afarensis. He appears to have been quite tall and slender. Scientists estimate that, had he grown into adulthood, the boy would have reached a height of 1.8 m (6 ft) and a weight of 68 kg (150 lb). The anatomy of the Turkana boy indicates that H. ergaster was particularly well adapted for walking and perhaps for running long distances in a hot environment (a tall and slender body dissipates heat well) but not for any significant amount of tree climbing
 The oldest humanlike fossils outside of Africa have also been classified as H. ergaster, dated around 1.75 million year’s old. These finds, from the Dmanisi site in the southern Caucasus Mountains of Georgia, consist of several crania, jaws, and other fossilized bones. Some of these are strikingly like East African H. ergaster, but others are smaller or larger than H. ergaster, suggesting a high degree of variation within a single population.
 H. ergaster, H. rudolfensis, and H. habilis, in addition to possibly two robust Australopiths, all might have coexisted in Africa around 1.9 million years ago. This finding goes against a traditional paleoanthropological view that human evolution consisted of a single line that evolved progressively over time—an australopith species followed by early Homo, then middle Homo, and finally H. sapiens. It appears that periods of species diversity and extinction have been common during human evolution, and that modern H. sapiens has the rare distinction of being the only living human species today.
 Although H. ergaster appears to have coexisted with several other human species, they probably did not interbreed. Mating rarely succeeds between two species with significant skeletal differences, such as H. ergaster and H. habilis. Many paleoanthropologists now believe that H. ergaster descended from an earlier population of Homo - perhaps one of the two known species of early Homo - and that the modern human line descended from H. ergaster.
 Sophisticated dating techniques combined with new fossil discoveries suggest that skeletal remains unearthed in Africa in 1995 come from the earliest known human ancestors to walk upright, according to a report published in the journal Nature on May 7, 1998.
 Researchers said the new findings indicated that Bipedalism (walking on two legs) emerged 4.07 million to 4.17 million years ago, about 500,000 years earlier than was previously believed. Experts said the new research had important implications for the study of human origins because Bipedalism is widely considered a key evolutionary adaptation that set the human lineage apart from that of other primates.
 The new findings are based on fossils found three years ago in northern Kenya near Lake Turkana. Scientists identified the fossils as belonging to a newly discovered prehumans species, Australopithecus anamensis, a creature with apelike teeth and jaws, long arms, and a small brain.
 Initial efforts to determine the age of the sediments in which the fossils were discovered failed, raising doubts about the fossils' antiquity. In addition, a lower-leg bones provide for critical evidence of Bipedalism was found in a different sedimentary layer, suggesting the bone could be younger or from a different species.
 Nevertheless, a new dating effort, led by anthropologist Meave G. Leakey of the National Museums of Kenya, used an argon-dating analysis technique that examined crystals in sedimentary volcanic ash. Researchers said the technique showed the lower-leg bone to be a “little” younger than the other fossils that were dated at 4.07 million to 4.17 million years ago. This finding indicated the remains belonged to the same species. The dating analysis was further supported by the subsequent discovery of dozens of new fossils in the area, the researchers said.
 Before the discovery of Australopithecus anamensis, the earliest known bipedal human ancestor was Australopithecus afarensis, the famous “Lucy” skeleton discovered in Ethiopia in 1974 and estimated to be three million to 3.7 million years old. Based on the new findings, some scientists believe that A. anamensis may be the most ancient species of australopithecine.
 One of the earliest defining human traits, Bipedalism - walking on two legs as the primary form of locomotion - evolved more than four million years ago. Other important human characteristics - such as a large and complex brain, the ability to make and use tools, and the capacity for language - developed more recently. Many advanced traits - including complex symbolic expression, such as art, and elaborate cultural diversity - emerged mainly during the past 100,000 years.
 Few books have rocked the world the way that.  On the Origin of Species did. Influenced in part by British geologist Sir Charles Lyell’s theory of a gradually changing earth, British naturalist Charles Darwin spent decades developing his theory of gradual evolution through natural selection before he published his book in 1859. The logical - and intensely controversial - extension of Darwin’s theory was that humans, too, evolved through the ages. For people who accepted the biblical view of creation, the idea that human beings shared common roots with lower animals was shocking. In this excerpt form.  On the Origin of Species, Darwin carefully sidesteps the issue of human evolution (as he did throughout the book), focussing instead on competition and adaptation in lower animals and plants
 Humans are primates. Physical and genetic similarities show that the modern human species, Homo sapiens, has a very close relationship to another group of primate species, the apes. Humans and the so-called great apes (large apes) of Africa - chimpanzees (including bonobos, or so-called pygmy chimpanzees) and gorillas - share a common ancestor that lived sometime between eight million and six million years ago. The earliest humans evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between six million and two million years ago come entirely from Africa. Humans and great apes of Africa share a common ancestor that lived between eight million and five million years ago.
 Most scientists distinguish among 12 to 19 different species of early humans. Scientists do not all agree, however, about how the species are related or which ones simply died out. Many early human species—probably the majority of them - left no descendants. Scientists also debate over how to identify and classify particular species of early humans, and about what factors influenced the evolution and extinction of each species.
 Tree of Human Evolution Fossil evidence indicates that the first humans evolved from ape ancestors at least six million years ago. Many species of humans followed, but only some left descendants on the branch leading to Homo sapiens. In this slide show, white skulls represent species that lived during the time indicated; gray skulls represent extinct human species.
 Early humans first migrated out of Africa into Asia probably between two million and 1.7 million years ago. They entered Europe in some respects later, generally within the past one million years. Species of modern humans populated many parts of the world much later. For instance, people first came to Australia probably within the past 60,000 years, and to the Americas within the past 35,000 years. The beginnings of agriculture and the rise of the first civilizations occurred within the past 10,000 years.
 The scientific study of human evolution is called Paleoanthropology. Paleoanthropology is a subfield of anthropology, the study of human culture, society, and biology. Paleoanthropologists search for the roots of human physical traits and behaviour. They seek to discover how evolution has shaped the potentials, tendencies, and limitations of all people. For many people, Paleoanthropology is an exciting scientific field because it illuminates the origins of the defining traits of the human species, as well as the fundamental connections between humans and other living organisms on Earth. Scientists have abundant evidence of human evolution from fossils, artifacts, and genetic studies. However, some people find the concept of human evolution troubling because it can seem to conflict with religious and other traditional beliefs about how people, other living things, and the world came to be. Yet many people have come to reconcile such beliefs with the scientific evidence.
 Modern and Early Humans have undergone major anatomical changes over the course of evolution. This illustration depicts Australopithecus afarensis (centre), the earliest of the three species; Homo erectus (left), an intermediate species; and Homo sapiens (right), a modern human. H. erectus and modern humans are much taller than A. afarensis and have flatter faces and much larger brains. Modern humans have a larger brain than H. erectus and almost flat face beneath the front of the braincase. National Geographic Society/John Sibbick
 All species of organisms originate through the process of biological evolution. In this process, new species arise from a series of natural changes. In animals that reproduce sexually, including humans, the term species refers to a group whose adult members regularly interbreed, resulting in fertile offspring—that is, offspring themselves capable of reproducing. Scientists classify each species with a unique, two-part scientific names. In this system, modern humans are classified as Homo sapiens.
 The mechanism for evolutionary change resides in genes—the basic units of heredity. Genes affect how the body and behaviour of an organism develop during its life. The information contained in genes can be change—a process known as mutation. The way particular genes are expressed - how they affect the body or behaviour of an organism - can also change. Over time, genetic change can alter a species’s overall way of life, such as what it eats, how it grows, and where it can live.
 Genetic changes can improve the ability of organisms to survive, reproduce, and, in animals, raise offspring. This process is called adaptation. Parents pass adaptive genetic changes to their offspring, and ultimately these changes become common throughout a population—a group of organisms of the same species that share a particular local habitat. Many factors can favour new adaptations, but changes in the environment often play a role. Ancestral human species adapted to new environments as their genes changed, altering their anatomy (physical body structure), physiology (bodily functions, such as digestion), and behaviour. Over long periods, evolution dramatically transformed humans and their ways of life.
 Geneticists estimate that the human line began to diverge from that of the African apes between eight million and five million years ago (paleontologists have dated the earliest human fossils to at least six million years ago). This figure comes from comparing differences in the genetic makeup of humans and apes, and then calculating how long it probably took for those differences to develop. Using similar techniques and comparing the genetic variations among human populations around the world, scientists have calculated that all people may share common genetic ancestors that lived sometime between 290,000 and 130,000 years ago.
 Humans belong to the scientific order named Primates, a group of more than 230 species of mammals that also includes lemurs, lorises, tarsiers, monkeys, and apes. Modern humans, early humans, and other species of primates all have many similarities as well as some important differences. Knowledge of these similarities and differences helps scientists to understand the roots of many human traits, as well as the significance of each step in human evolution.
 The origin of our own species, Homo sapiens, is one of the most hotly debated topics in Paleoanthropology. This debate centers on whether or not modern humans have a direct relationship to H. erectus or to the Neanderthals, a well-known, more modern group of humans who evolved within the past 250,000 years. Paleoanthropologists commonly use the term anatomically modern Homo sapiens to distinguish people of today from these similar predecessors.
 Traditionally, paleoanthropologists classified as Homo sapiens any fossil human younger than 500,000 years old with a braincase larger than that of H. erectus. Thus, many scientists who believe that modern humans descend from a single line dating back to H. erectus use the name archaic Homo sapiens to refer to a wide variety of fossil humans that predate anatomically modern H. sapiens. The term archaic denotes a set of physical features typical of Neanderthals and other species of late Homo before modern Homo sapiens. These features include a combination of a robust skeleton, a large but low braincase (positioned reasonably behind, than over, the face), and a lower jaw lacking a prominent chin. In this sense, Neanderthals are sometimes classified as a subspecies of archaic H. sapiens - H. Sapiens neanderthalensis. Other scientists think that the variation in archaic fossils existently falls into clearly identifiable sets of traits, and that any type of human fossil exhibiting a unique set of traits should have a new species name. According to this view, the Neanderthals belong to their own species, H. neanderthalensis.
 The Neanderthals lived in areas ranging from western Europe through central Asia from about 200,000 to about 28,000 years ago. The name Neanderthal (sometimes spelled Neanderthal) comes from fossils found in 1856 in the Feldhofer Cave of the Neander Valley in Germany (tal - a modern form of thal - means “valley” in German). Scientists realized several years later that prior discoveries - at Engis, Belgium, in 1829 and at Forbes Quarry, Gibraltar, in 1848 - also represented Neanderthals. These two earlier discoveries were the first early human fossils ever found. In the past, scientists claimed that Neanderthals differed greatly from modern humans. However, the basis for this claim came from a faulty reconstruction of a Neanderthal skeleton that showed it with bent knees and a slouching gait. This reconstruction gave the common but mistaken impression that Neanderthals were dim-witted brutes who lived a crude lifestyle. On the contrary, Neanderthals, like the species that preceded them, walked fully upright without a slouch or bent knees. In addition, their cranial capacity was quite large at about 1,500 cu cm (about 90 cu in), larger on average than that of modern humans. (The difference probably relates to the greater muscle mass of Neanderthals as compared with modern humans, which usually correlates with a larger brain size.)
 Compared with earlier humans, Neanderthals had a high degree of cultural sophistication. They appear to have performed symbolic rituals, such as the burial of their dead. Neanderthal fossils - including a number of fairly complete skeletons—are quite common compared with those of earlier forms of Homo, in part because of the Neanderthal practice of intentional burial. Neanderthals also produced sophisticated types of stone tools known as Mousterian, which involved creating blanks (rough forms) from which several types of tools could be made.
 Along with many physical similarities, Neanderthals differed from modern humans in several ways. The typical Neanderthal skull had a low forehead, a large nasal area (suggesting a large nose), a forward-projecting nasal and cheek region, a prominent brow ridge with a bony arch over each eye, a nonprojecting chin, and obvious space behind the third molar (in front of the upward turn of the lower jaw).
 Neanderthal and Modern Human Skulls the skull of Homo neanderthalensis (left) differs considerably from that of anatomically modern humans, or Homo sapiens (right). Neanderthals had thick-walled skulls, sloping foreheads, and heavy brow ridges. This contrasts with the thin-walled skulls, high foreheads, and flat faces of modern humans. Neanderthals also had more pronounced and powerful jaws but less of a chin than do modern humans.
 Neanderthal also had a more heavily built and large-boned skeleton than do modern humans. Other Neanderthal skeletal features included a bowing of the limb bones in some individuals, broad scapulae (shoulder blades), hip joints turned outward, a long and thin pubic bone, short lower leg and arm bones relative to the upper bones, and large surfaces on the joints of the toes and limb bones. Together, these traits made a powerful, compact body of short stature—males averaged 1.7 m (5 ft 5 in) tall and 84 kg (185 lb), and females averaged 1.5 m (5 ft) tall and 80 kg (176 lb).
 The short, stocky build of Neanderthals conserved heat and helped them withstand extremely cold conditions that prevailed in temperate regions beginning about 70,000 years ago. The last known Neanderthal fossils come from western Europe and date from approximately 36,000 years ago.
 At the same time as Neanderthal populations grew in number in Europe and parts of Asia, other populations of nearly modern humans arose in Africa and Asia. Scientists also commonly refer to these fossils, which are distinct from but similar to those of Neanderthals, as archaic. Fossils from the Chinese sites of Dali, Maba, and Xujiayao display the long, low cranium and large face typical of archaic humans, yet they also have features similar to those of modern people in the region. At the cave site of Jebel Irhoud, Morocco, scientists have found fossils with the long skull typical of archaic humans but also the modern traits modern of measure have higher forehead and flatter midface. Fossils of humans from East African sites older than 100,000 years - such as Ngaloba in Tanzania and Eliye Springs in Kenya - also seem to show a mixture of archaic and modern traits.
 Ancient Human Footprints the oldest known footprints of an anatomically modern human are embedded in rock north of Cape Town, South Africa. Geologist David Roberts and paleoanthropologists Lee Berger announced the discovery of the footprints in August 1997. A human being made the footprints about 117,000 years ago by walking through wet sand, which eventually hardened into rock.
 The oldest known fossils that possess skeletal features typical of modern humans date from between 130,000 and 90,000 years ago. Several key features distinguish the skulls of modern humans from those of archaic species. These features include a much smaller brow ridge, if any; a globe-shaped braincase; and a flat or only projecting face of reduced size, located under the front of the braincase. Among all mammals, only humans have a face positioned directly beneath the frontal lobe (forward-most area) of the brain. As a result, modern humans tend to have a higher forehead than did Neanderthals and other archaic humans. The cranial capacity of modern humans ranges from about 1,000 to 2,000 cu cm (60 to 120 cu in), with the average being about 1,350 cu cm (80 cu in).
 Scientists have found both fragmentary and nearly complete cranial fossils of early anatomically modern Homo sapiens from the sites of Singha, Sudan; Omo, Ethiopia; Klasies River Mouth, South Africa; and Skhûl Cave, Israel. Based on these fossils, many scientists conclude that modern H. sapiens had evolved in Africa by 130,000 years ago and started spreading to diverse parts of the world beginning on a route through the Near East sometime before 90,000 years ago.
 The 1994 discovery in Sierra de Atapuerca, Spain, of well-preserved hominid bones pushed back the date for the arrival in Europe of our early human ancestors to 800,000 years ago. Anthropology professor Brian Fagan discusses these and other recent findings about the first members of the human family to live in Europe, and he dispels the widespread myth that Neanderthals were dumb and brutish.
 Paleoanthropologists are engaged in an ongoing debate about where modern humans evolved and how they spread around the world. Differences in opinion rest on the question of whether the evolution of modern humans took place in a small region of Africa or over a broad area of Africa and Eurasia. By extension, opinions differ as to whether modern human populations from Africa displaced all existing populations of earlier humans, eventually resulting in their extinction. Those who think modern humans originated only in Africa and then spread around the world support what is known as the out of Africa hypothesis. Those who think modern humans evolved over a large region of Eurasia and Africa support the so-called multi-regional hypothesis.
 Researchers have conducted many genetic studies and carefully assessed fossils to determine which of these hypotheses agrees more with scientific evidence. The results of this research do not entirely confirm or reject either one. Therefore, some scientists think a compromise between the two hypotheses is the best explanation. The debate between these views has implications for how scientists understand the concept of race in humans. The question raised is whether the physical differences among modern humans evolved deep in the past or relatively recently.
 Scientists reported in the May 16, 1996, issued of the journal Nature that later Neanderthals likely interacted, perhaps even traded goods, with Cro-Magnons, their anatomically modern human neighbours. Researchers in Arcy-sur-Cure, France, 35 km (22 mi) southeast of Auxerre, said they found hominid fossils alongside bone and ivory jewellery nearly identical to artifacts attributed to anatomically modern humans.
 The fossils were found in Arcy-sur-Cure long ago, but scientists could not determine to which human species the bones belonged. The shape of the inner ear gave anthropologists a clue that the 34,000-year-old fossil remains found decades ago were from a Neanderthal, not a modern human. The ear morphology may also shed light on the relationship of Neanderthals to humans of today.
 The ornaments found at the Arcy site included a bone ring, grooved animal teeth, and animal claws with small holes made at one end, presumably so they could be strung on a cord and hung around the neck. They resemble jewellery found at sites in northern Spain and central and southwestern France where Cro-Magnons lived. Anthropologists Jean-Jacques Hublin of the Musée de l'Homme in Paris, France, and Fred Spoor of University College in London, England, the coauthors of the report, concluded that the presence of jewellery at the Arcy site nearly identical to jewellery at the Cro-Magnon sites indicated that Neanderthals probably traded with Cro-Magnons rather than imitated the style of their contemporary neighbours. The resemblance was too close in appearance to nearby Cro-Magnon finds for imitation, they believe. Anatomically modern humans first arrived in Europe about 40,000 years ago.
 The relationship of Neanderthals to modern humans has long been a topic of scientific debate. The fossil record suggests Neanderthals disappeared from 30,000 to 40,000 years ago. Neanderthals characteristics differ most obviously from anatomically modern humans in the formation of the skull and face. The Neanderthal had a sloping forehead, no chin, protruding browridges, large teeth, and strong jaw muscles. The brains of Neanderthals were larger than those of modern humans. Aside from the face, the Neanderthals had thicker bones and larger musculature, long bodies and short legs. Some of the Neanderthal's features, especially body proportion, were cold-weather adaptations similar to those developed by modern people living in arctic conditions, such as the Inuit.
 Hublin and Spoor used high-resolution, computerized X rays to scrutinize a temporal (side) bone from the skull of a one-year-old Neanderthal. They found that the ear canals-known as the labyrinth-within the bone was distinctly different in size and location from the same bone in Homo erectus, an early human ancestor, and anatomically modern humans. The labyrinth consists of three hollow rings and is involved in maintaining balance.
 Some scientists classify the Neanderthal as a separate species, Homo neanderthalensis. Because the features of the Neanderthal's labyrinth do not exist in modern humans, the scientists believe that the muscular hominid belongs to a separate species, or at least is not an ancestor of modern humans. Some experts believe that Neanderthals evolved from archaic Homo sapiens into an evolutionary dead end. Other researchers have speculated that later Neanderthals may have interbred with Cro-Magnons, but Hublin argues that his new evidence does not support that theory. In their report to Nature, Hubin and Spoor said their findings did not show any trend toward more modern human characteristics.
 Archives consist of articles that originally appeared in Collier's Year Book because they were published shortly after events occurred, they reflect the information available at that time. Cross references refer to Archive articles of the same year. Archaeology Top stories in archaeology in 1995 included new dates for the Neanderthals and the discovery of the frozen bodies of a Scythian equestrian and an Inca woman. Last Neanderthals. New dates from Zafarraya Cave in southern Spain suggest that Neanderthals were alive millennia after scholars assumed they had become extinct. The dates also suggest that Neanderthals coexisted with modern humans in Western Europe for 10,000 years or more, rather than being replaced quickly by overwhelmingly superior modern groups, as many archaeologists have argued. Samples of animal bones and teeth found with Neanderthal remains and artifacts were subjected to both carbon and thorium/uranium testing, producing dates of around 30,000 years ago. In northern Spain stone tools of a type generally associated with modern humans appeared between 40,000 and 38,000 years ago. Elsewhere in Europe, Neanderthal and modern human populations mixed, but in southern Spain, Neanderthals survived without strong biological or cultural interaction with the newcomers, probably because they were isolated. The existence of a Neanderthal population in southern Spain long after modern humans arrived in the north makes it unlikely that modern humans reached Western Europe from Africa via the Strait of Gibraltar. Frozen Bodies. A frozen Scythian equestrian, dated to around 500 Bc, was found in Siberia's Altai Mountains. The man, 25-30 years of age, was buried with his horse, bow and arrows, an ax, and a knife. He was wearing a thick wool cap, high leather boots, and a coat of marmot and sheepskin. On his right shoulder is a large tattoo of a stag. The horse's harness was decorated with wood carvings of griffins and animals covered in gold foil. The horseman's body, like the body of a richly attired woman discovered in the same area in 1993, had been buried in a log-lined chamber under more than 2 metres (7 feet) of permafrost. The horseman's mummy was moved to a Moscow lab for preservation. In southern Peru the frozen body of an Inca woman of 12-14 years of age, probably a sacrificial victim, was found near the summit of a 6,300-metre (20,700-foot) peak. The remains, dated around Ad. 1500, were discovered 60 metres (200 feet) below a stone sanctuary. The peak is usually ice-covered, but the recent eruption of a nearby volcano had blanketed it with ash. The dark-coloured ash absorbed the sun's warmth instead of reflecting it as the ice had, and the ice melted. Two more bodies were later found farther down the slope, along with the remains of a camp used by the sanctuary's builders and priests. Several small figurines of gold, silver, gold-copper alloy, and oyster-like shell were found near the girl's body, and two had been wrapped in the layers of wool and cotton cloth in which it was bundled. The body had an elaborate feather headdress. The most important aspect of the find is that the bodies were frozen, providing an opportunity to study Inca diet and health. Early Bone Points From Africa. Archaeologists dated barbed bone points found in eastern Zaire to 90,000 years or older. The ability to make such tools at this early date supports an African origin of behaviourally as well as biologically modern humans, the archaeologists said. Barbed points do not occur before 14,000 to 12,000 years ago at sites in Eurasia. The barbed points, and unbarbed points and a flat dagger-shaped object with rounded edges, came from three sites at Katanda in the Semliki River valley. Dating of the immediately overlying sands and hippo teeth found in them suggests an age of 80,000 to 90,000 years ago for the site. The barbed points were found with mammal and fish remains, of which catfish were most abundant. The catfish were probably caught during the rainy season when they spawned on the inundated floodplain and were easy to catch. The Katanda sites indicate that a complex bone industry and seasonal use of aquatic resources had developed by 90,000 years ago, following a specialized subsistence pattern most often associated in Europe with the end of the Ice Age nearly 80,000 years later. Earliest Weaving. Impressions of woven fabric on four fragments of clay from Pavlov I, an Upper Paleolithic site in the Czech Republic, have proved to be the earliest evidence of weaving ever found. The fragments were carbon dated in 1995 to between 26,980 and 24,870 years ago. The dates are at least 7,000 to 10,000 years earlier than those of any other evidence of weaving. Two of the better-preserved specimens show tightly spaced rows characteristic of a finely woven bag or mat. The fineness and the method of weaving used, known as twining, suggested that the material may have been produced using a loom and that the weavers were accomplished and not experimenting with a new technology. This means that the actual advent of weaving may be even earlier than the date of the Pavlov specimens. The impressions from Pavlov I show that a wide range of items, such as baskets, nets, and snares, were likely to have been available to the hunter-gatherers of the Upper Paleolithic. Chauvet Art. The spectacular decorated Grotte Chauvet in southern France, whose discovery was announced in January, has proved to have the world's oldest known cave paintings, carbon dated to more than 30,000 years ago. The cave also contains human and bear footprints, flints, bones, and hearths. Submarines and Archaeology. The Confederate vessel Hunley, the first submarine ever to sink a warship in combat, was discovered in May off the coast of Charleston, SC. Famous for its attack on the U.S.S. Housatonic during the American Civil War, the submarine went down shortly after sinking the ship on February 17, 1864. The Hunley was made from an iron locomotive boiler and carried a copper canister filled with 40 kilograms (90 pounds) of black powder at the end of a long spar. Manned by volunteers who powered its hand-cranked propeller, the Hunley placed its charge alongside the target and then backed up, detonating the explosive with a long cord that triggered the firing mechanism. The U.S. Navy announced in 1995 that the NR-1, a formerly classified submarine, would be used to search the Mediterranean seafloor for ancient shipwrecks. The submarine's windows and extensive light and sonar arrays make it perfect for searching for ancient wrecks, and its remote-controlled arm can retrieve objects. The NR-1, the world's smallest nuclear submarine, will enable archaeologists to study the open-water trade routes of antiquity, not just the coastal routes. Its first archaeological mission will be to explore the trade route between Carthage, on the North African coast, and Rome. The discovery in 1995 of the Japanese submarine I-52, which was sunk on June 23, 1944, deepened concerns about the growing accessibility of the deep oceans. American and British treasure hunters were in a race to find the sub and its cargo, 2 metric tons of gold. Both groups hired Russian research vessels with sophisticated sonar and photographic capabilities. In May the American group found the submarine 5,000 metres (17,000 feet) down in the mid-Atlantic. The discoverer stated that the gold, valued at $25 million, would be recovered with the least disturbance possible to the vessel, which may still hold the remains of 109 men. The Japanese government may retain title to both vessel and contents. Nonetheless, the implications are clear: anyone with sufficient financial backing can locate and, if the person is unscrupulous, pillage shipwrecks - ancient, medieval, or modern. Egyptian Tombs. Important discoveries were made in 1995 at both well-known and newly found cemeteries in Egypt. At Saqqara, near Cairo, French archaeologists discovered the necropolis of three queens of the Sixth Dynasty Pharaoh Pepi I (2332-2283 Bc). A pyramid 45 metres (150 feet) high found buried in sand at Saqqara is the tomb of Queen Meretites, a descendant of Pepi I. It may provide information on a turbulent period at the end of the dynasty when powerful governors paid only nominal allegiance to the pharaoh. Egyptian and Canadian archaeologists located a vast pre-dynastic cemetery at Tell Hassan Dawoud, 100 kilometres (60 miles) east of Cairo, dating to 3000 Bc or earlier. Many of the tombs yielded gold, marble, and ceramic artifacts. Not all of the burials had grave offerings, however, suggesting that Egypt's society was strongly stratified 500 years before the pharaohs. The largest tomb ever found in Egypt's Valley of the Kings was partly explored in 1995. The tomb was the burial place of many of the 100 or more offspring of Rameses II, who reigned around 1279-1212 Bc. Artifacts recovered from the tomb bear the names of at least four of his sons, and the name of the firstborn, Amon-her-khepeshef, are painted on a wall. Until this discovery little was known about most of the pharaoh's offspring. The tomb is unlikely to hold any great treasure, since a papyrus in Turin records its robbery in 1150 Bc. Its chief importance is the information it may yield about family burials and tomb plans of New Kingdom royalty. Syrian Bronze Age Cemetery. Archaeologists working at Tell es-Sweyhat on the Euphrates River in northern Syria discovered an intact tomb in what may be an unplundered cemetery containing up to 150 such tombs. Investigation of a number of tombs could provide a sample of human remains large enough to determine biological relationships and social organization of the people through DNA analysis. A large sample would also allow study of diet and disease in the population. The tomb, dated around 2500-2250 Bc, held the remains of several individuals. More than 100 ceramic vessels were in the tomb, along with incised bone, beads, and shells. Copper and bronze objects included daggers, axes, and a javelin. Bones of numerous pigs, sheep, goats, and cows in the tomb are the remains of funerary offerings. Bird eggs had been placed in the eye sockets of one animal skull
 Still, it was the Primates, of whom are an order of mammals that includes humans, apes, which are the closest living relatives to humans, monkeys, and some less familiar mammals, such as tarsiers, lorises, and lemurs. Humans and other primates share a common evolutionary descent. For this reason, primates have always fascinated scientists because their physical features, social organization, behavioural patterns, and fossil remains provide clues about our earliest human ancestors.
 Primates evolved from tree-dwelling ancestors. Although some species, such as humans, have since taken to the ground, all primates’ share features that are related to their tree-climbing ancestry. These include arms and legs that can move more freely than those of most other mammals, flexible fingers and toes, forward-facing eyes that can judge distances accurately - a vital aid when moving about high above the ground - and large brains.
 Primates live in a wide range of habitats but are restricted by their need for warmth. Most primates live in tropical jungles or dry forests, but some live in dry grasslands, and others have settled in cold, mountainous regions of China and Japan. The world's most northerly primate, the Japanese macaque, has learned to bathe in hot springs to survive through the winter snows. In parts of the tropics, monkeys can be seen within a few miles of busy city centers, but despite this adaptability, the majority of the world’s primates retain a close dependence on trees. Apart from humans, baboons are the only primates that have fully made the transition to life out in the open, and even they instinctively climb to safety if danger threatens.
 Some primates, especially the smaller species, are active only at night, or nocturnal, while others are diurnal, active during the day. Most primate species - particularly monkeys - are highly sociable animals, sometimes living in troops of more than 100 members. Smaller primates, especially nocturnal ones, tend to be solitary and secretive.
 Primates range in size from quite small to quite large. The world's largest species, the lowland gorilla at 200 kg (400 lb) is more than 6,000 times the weight of the smallest primate, the pygmy mouse lemur from Madagascar. Measuring just 20 cm (8 in) from nose to tail, and weighing about 30 g (1 oz), this tiny animal was first identified about two centuries ago, but was later assumed to be extinct until its rediscovery in 1993.
 There are about 235 species of primates. Scientists use more than one way to classify primates, and one system divides the order into two overall groups, or suborders: the prosimians and the anthropoids.
 The prosimians, or "primitive primates," make up the smaller of these two groups, with about 60 species, and include lemurs, pottos, galagos, lorises, and, in some classification systems, tarsiers. Lemurs are only found on the islands of Madagascar and Comoros, where they have flourished in isolation for millions of years. Pottos and galagos are found in Africa, while lorises and tarsiers are found in southeast Asia. Typical prosimians are small to medium-sized mammals with long whiskers, pointed muzzles, and well-developed senses of smell and hearing. Most prosimians are nocturnal, although in Madagascar some of the larger lemurs are active by day.
 In the past, tree shrews were often classified as primates, but their place in mammal classification has been the subject of much debate. Today, based on reproductive patterns and on new fossil evidence, most zoologists classify them in an order of their own, the Scandentia.
 The remainder of the world's primates makes up the anthropoid, or “humanlike” suborder, which contains about 175 species. This group consists of humans, apes, and monkeys. Most anthropoids, apart from baboons, have flat faces and a relatively poor sense of smell. With a few exceptions, anthropoids are almost always active during the day, and they find their food mainly by sight.
 Evolution has had a marked effect on the thumbs and big toes of primates. In most mammals, these digits bend in the same plane as the other fingers and toes. Nevertheless, in many primates, the thumbs or big toes are opposable, meaning that they are set apart in a way that permits them to meet the other digits at the tips to form a circle. This enables primates to grip branches, and equally importantly, pick up and handle small objects. Instead of having claws, most primates have flat nails that cover soft, sensitive fingertips—another adaptation that helps primates to manipulate objects with great dexterity.
 Primate skulls show several distinctive features. One of these is the position of the eyes, which in most species is on the front of the skull looking forward, rather than on the side of the skull looking to the side as in many other mammals. The two forward-facing eyes have overlapping fields of view, which give primates stereoscopic vision. Stereoscopic vision permits accurate perception of distance, which is helpful for handling food or swinging from branch to branch high above the ground. Another distinctive feature of primate skulls, in anthropoids particularly, is the large domed cranium that protects the brain. The inside surface of this dome clearly shows the outline of an unusually large brain - one of the most remarkable characteristics of this group. The shapes of anthropoid brains are different from other mammals; the portion of the brain devoted to vision is especially large, while the portion devoted to smell is comparatively small.
 The primate order includes a handful of species that live entirely on meat (carnivores) and a few that are strict vegetarians (herbivores), but it is composed chiefly of animals that have varied diets (omnivores). The carnivorous primates are the four species of tarsiers, which live in Southeast Asia. Using their long back legs, these pocket-sized nocturnal hunters leap on their prey, pinning it down with their hands and then killing it with their needle-sharp teeth. Tarsiers primarily eat insects but will also eat lizards, bats, and snakes.
 Other prosimians, such as galagos and mouse lemurs, also hunt for insects, but they supplement their diet with different kinds of food, including lizards, bird eggs, fruit, and plant sap. This opportunistic approach to feeding is seen in the majority of monkeys and in chimpanzees. Several species of monkeys, and chimpanzees, but not the other apes, have been known to attack and eat other monkeys. Baboons, the most adept hunters on the ground, often eat meat and sometimes manage to kill small antelope.
 Primates display a wide range of mating behaviours. Solitary primates, such as aye-ayes and orangutans, have relatively simple reproductive behaviour. Within the territory that each male controls, several females live, each with their own territory. The male mates with any females within his territory that are receptive. Other species, such as gibbons, form small family groups consisting of a monogamous pair and their young. Gorillas form harems, in which one adult male lives with several adult females and their young. Among social primates, breeding can be complicated by the presence of many adults. Males may cooperate in defending their troop's territory, but they often fight each other for the chance to mate. In some species, only the dominant male mates with the females in the group. Chimpanzee females mate promiscuously with several adult males, although they usually pair up with one of the high-ranking males during the final few days of estrus, spending all of their time together and mating together exclusively.
 Primates have the most highly developed brains in the animal kingdom, rivalled only by those of dolphins, whales, and possibly elephants. Anthropoid primates in particular are intelligent and inquisitive animals that are quick to learn new patterns of behaviour. This resourcefulness enables them to exploit a wide range of foods and may help them to escape attacks by predators.
 Many zoologists believe that primates' large brains initially evolved in response to their tree-dwelling habits and their way of feeding. Anthropoid primates, which have the largest brains, live in a visual world, relying on sight to move about and to locate and manipulate food. Unlike smell or hearing, vision generates a large amount of complex sensory information that has to be processed and stored. In primate brains, these operations are carried out by a portion of the brain called the cerebral cortex, which evolved into such a large structure that the rest of the brain is hidden beneath it. Some unrelated mammals, such as squirrels, also live in trees, but they have less-developed eyesight and much smaller brains.
 Increased brainpower has had impressive effects on the way primates live. It has helped them to move about and find food as well as enabled them to develop special skills. One of the most remarkable of these is toolmaking, seen in chimpanzees and, to a far greater extent, in humans. Toolmaking, as opposed to simple tool use, involves a preconceived image of what the finished tool should look like - something that is only possible with an advanced brain.
 The intelligence of primates is also evident in their social behaviour. For species that live in groups, daily life involves countless interactions with relatives, allies, and rivals. Mutual cleaning and grooming of the fur, which removes parasites, helps to reinforce relationships, while threats - sometimes followed by combat - maintain the hierarchy of dominance that permeates typical primate troops.
 Primates use a variety of methods to communicate. In solitary prosimians, when animals are not within sight of each other, communication is often accomplished by using scents. Such animals use urine, faeces, or special scent glands to mark territory or to communicate a readiness to mate. In social anthropoids, visual and vocal signals are much more important. Most monkeys and apes communicate with a complex array of facial expressions, some of which are similar to the facial expressions used by humans
 The earliest fossils of primates that have been discovered date from the end of the Cretaceous Period, about 65 million years ago. These early fossils include specimens of a species called Notharctus, which resembles today's lemurs and had a long pointed snout. The ancestors of another prosimian group, the tarsiers, are known from fossils that date back to the early Eocene Epoch, about 50 million years ago. In 1996 researchers in China recovered fossil bones of a primitive primate no bigger than a human thumb. The animal, named Eosimias, lived 45 million years ago. Many scientists believe that Eosimias is an example of a transitional animal in the evolution of prosimians to anthropoids
 The origin of anthropoids has proven to be difficult to pin down. A single anthropoid fossil has been found that may come from the Eocene Epoch, but conclusive fossil evidence of anthropoids does not appear until the Oligocene Epoch, which began 38 million years ago. These early anthropoids belonged to a lineage that led to the catarrhine primates - the Old World monkeys, apes, and humans. The platyrrhine primates, which include all New World monkeys, are presumed to have diverged from the Old World monkeys during the Eocene Epoch. They evolved in isolation on what was then the island continent of South America. Genetic analysis shows that New World monkeys clearly share a common ancestry with the catarrhines, which means that they must have reached the island continent from the Old World. Exactly how they did this is unclear. One possibility is that they floated across from Africa on logs or rafts of vegetation, journeying across an Atlantic Ocean that was much narrower than it is today
 Of all primate groups, the apes and the direct ancestors of humans have been the most intensively studied. One key question concerns when the two groups diverged. Based on the comparisons of genes and the structure of body parts, scientists think that the line leading to the orangutan diverged from the one leading to humans about 12 million years ago. The ancestral line leading to chimpanzees did not diverge until more recently, probably between 5 and 7 million years ago. This evidence strongly suggests that chimpanzees are our closest living relatives.  Apes and monkeys also play an important role in the field of medical research. Because their body systems work very much like our own, new vaccines and new forms of surgery are sometimes tried on apes and monkeys before they are approved for use on humans. Species that are most often used in this way include chimpanzees, baboons, and rhesus monkeys. This kind of animal experimentation has undoubtedly contributed to human welfare, but the medical use of primates is an increasingly controversial area, particularly when it involves animals captured in the wild.
 The species most under threats are those that have been affected by deforestation. This has been particularly severe in Madagascar, the only home of the lemurs, and it is also taking place at a rapid rate in Southeast Asia, threatening gibbons and orangutans. The almost total destruction of Brazil's Atlantic rainforest has proved catastrophic for several species, including the lion tamarins, which are found only in this habitat. Primates are also threatened by collection for the pet trade and by hunting. Illegal hunting is the chief threat facing the mountain gorilla, a rare African subspecies that lives in the politically volatile border region straddling Uganda, Rwanda, and the Democratic Republic of the Congo.
 In the face of these threats, urgent action is currently underway to protect many of these endangered species. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) currently forbids the export of many primates, although not all countries have chosen to follow this law. More direct methods of species preservation include habitat protection and captive breeding programs. In some cases - for example, the lion tamarin - these programs have met with considerable success. However, without the preservation of extensive and suitable natural habitats, many primate species are destined for extinction.
 Our closest living relative are three surviving species of great apes: the gorilla, the common chimpanzee, And the pygmy chimpanzee (also known as bonobo0). Their confinement to Africa, along with abundant fossil evidence, strongly suggests that they also played the earliest stages of human evolution out in Africa, human history, as something separate from the history of animals, occurring about seven million years ago (estimates range from five to nine million years ago). Around that time, a population of African apes broke off into several populations, of which one preceded to evolve into modern gorillas, a second into the two modern chimps, and the third into humans. The gorilla line apparently split slightly before the split between the chimp and the human lines.
 The primate, is the order of mammals that includes humans, apes, which are the closest living relatives to humans, monkeys, and some less familiar mammals, such as tarsiers, lorises, and lemurs. Humans and other primates share a common evolutionary descent. Consequently, primates have always fascinated scientists because their physical features, social organization, behavioural patterns, and fossil remains provide clues about our earliest human ancestors.
 Primates evolved from tree-dwelling ancestors. Although some species, such as humans, have since taken to the ground, all primates’ share features that are related to their tree-climbing ancestry. These include arms and legs that can move more freely than those of most other mammals, flexible fingers and toes, forward-facing eyes that can judge distances accurately - a vital aid when moving about high above the ground - and large brains.
 Primates live in a wide range of habitats but are restricted by their need for warmth. Most primates live in tropical jungles or dry forests, but some live in dry grasslands, and others have settled in cold, mountainous regions of China and Japan. The world's most northerly primate, the Japanese macaque, has learned to bathe in hot springs to survive through the winter snows. In parts of the tropics, monkeys can be seen within a few miles of busy city centres, but despite this adaptability, most of the world’s primates retain a close dependence on trees. Apart from humans, baboons are the only primates that have fully made the transition to life out in the open, and even they instinctively climb to safety if danger threatens.
 Some primates, especially the smaller species, are active only at night, or nocturnal, while others are diurnal, active during the day. Most primate species - particularly monkeys - are highly sociable animals, sometimes living in troops of more than 100 members. Smaller primates, especially nocturnal ones, tend to be solitary and secretive.
 Primates range in size from quite small to quite large. The world's largest species, the lowland gorilla at 200 kg. (400 lb.) is more than 6,000 times the weight of the smallest primate, the pygmy mouse lemur from Madagascar. Measuring only 20 cm. (8 in.) from nose to tail, and weighing about 30 g. (1 oz.), this tiny animal was first identified about two centuries ago, but was later assumed to be extinct until its rediscovery in 1993.
 There are about 235 species of primates. Scientists use more than one way to classify primates, and one system divides the order into two overall groups, or suborders: the prosimians and the anthropoids.
 The prosimians, or "primitive primates," make up the smaller of these two groups, with about 60 species, and include lemurs, Pontos, galagos, lorises, and, in some classification systems, tarsiers. Lemurs are only found on the islands of Madagascar and Comoros, where they have flourished in isolation for millions of years. Pontos and galagos are found in Africa, while lorises and tarsiers are found in southeast Asia. Typical prosimians are small to medium-sized mammals with long whiskers, pointed muzzles, and well-developed senses of smell and hearing. Most prosimians are nocturnal, although in Madagascar some larger lemurs are active by day.
 In the past, tree shrews were often classified as primates, but their place in mammal classification has been the subject of much debate. Today, based on reproductive patterns and on new fossil evidence, most zoologists classify them in an order of their own, the Scandentia.
 The remainder of the world's primates makes up the anthropoid, or “humanlike” suborder, which contains about 175 species. This group consists of humans, apes, and monkeys. Most anthropoids, apart from baboons, have flat faces and a poor sense of smell. With a few exceptions, anthropoids are usually active during the day, and they find their food mainly by sight.
 Apes are found only in Africa and Asia. They have no tails, and their arms are longer than their legs. Monkeys from Central and South America, known as New World monkeys, have broad noses and nostrils that open sideways. They are called platyrrhine, which means broad-nosed. Monkeys from Africa and Asia, known as Old World monkeys, have narrow noses and nostrils that face downward - a characteristic also seen in apes and humans. Old World Monkeys are called catarrhine, which means downward-nosed.
 During evolution, primates have kept several physical features that most other mammals have lost. One of these is the clavicle, or collarbone. In primates, the clavicle forms an important part of the shoulder joint. It helps to stabilize the shoulder, permitting a primate to support its weight by hanging from its arms alone - something that few other mammals can do. Some primates, particularly gibbons and the siamang, use this ability to move through the trees from one branch to another by swinging from arm to arm. This type of locomotion is called the brachiation.
 During evolution, many mammals have gradually lost limb bones as they have adapted to different ways of life: horses, for example, have lost all but a single toe on each foot. Nearly all primates, by contrast, have retained a full set of five fingers and toes, and usually these digits have become increasingly flexible as time has gone through. In the aye-aye, a prosimian from Madagascar, the third finger on each hand is long and thin with a special claw at the end. Aye-ayes use these bony fingers to extract insect grubs from bark.
 Evolution has affected the thumbs and big toes of primates. In most mammals, these digits bend in the same plane as the other fingers and toes. However, in many primates, the thumbs or big toes are opposable, meaning that they are set apart in a way that permits them to meet the other digits at the tips to form a circle. This enables primates to grip branches, and equally importantly, pick up and handle small objects. Instead of having claws, most primates have flat nails that cover soft, sensitive fingertips—another adaptation that helps primates to manipulate objects with great dexterity.
 Tails are absent in humans and apes, but in most monkeys and prosimians, the tail plays a special role in maintaining balance during movement through the treetops. Many New World monkeys have prehensile tails, which can be wrapped around branches, gripping them like an extra hand or foot.
 Primate skulls show several distinctive features. One of these is the position of the eyes, which in most species is on the front of the skull looking forward, rather than on the side of the skull looking to the side as in many other mammals. The two forward-facing eyes have overlapping fields of view, which give primates stereoscopic vision. Stereoscopic vision permits accurate perception of distance, which is helpful for handling food or swinging from branch to branch high above the ground. Another distinctive feature of primate skulls, in anthropoids particularly, is the large domed cranium that protects the brain. The inside surface of this dome clearly shows the outline of an unusually large brain - one of the most remarkable characteristics of this group. The shapes of anthropoid brains are different from other mammals: The portion of which the distributive contribution whereby the brain is enwrapped to the visual modalities is especially large, while the compensable portion of attribution to smell is comparatively small.
 The primate order includes a handful of species that live entirely on meat (carnivores) and a few that are strict vegetarians (herbivores), but it is composed chiefly of animals that have varied diets (omnivores). The carnivorous primates are the four species of tarsiers, which live in Southeast Asia. Using their long back legs, these pocket-sized nocturnal hunters leap on their prey, pinning it down with their hands and then killing it with their needle-sharp teeth. Tarsiers primarily eat insects but will also eat lizards, bats, and snakes.
 Other prosimians, such as galagos and mouse lemurs, also hunt for insects, but they supplement their diet with different kinds of food, including lizards, bird eggs, fruit, and plant sap. This opportunistic approach to feeding is seen in most of monkeys and in chimpanzees. Several species of monkeys, and chimpanzees, but not the other apes, have been known to attack and eat other monkeys. Baboons, the most adept hunters on the ground, often eat meat and sometimes manage to kill small antelope.
 Most apes and monkeys eat a range of plant-based foods, but a few specialize in eating leaves. South American howler monkeys and African colobus monkeys eat the leaves of many different trees, but the proboscis monkey on the island of Borneo is more selective, surviving largely on the leaves of mangroves. These leaf-eating monkeys have modified digestive systems, similar to cows, which enable them to break down food that few other monkeys can digest. Other apes and monkeys eat mostly fruit, while some marmosets and lemurs depend on tree gum and sap.
 Compared with many other mammals, primates have  few young, and their offspring take a long time to develop. The gestational period, the time between conception and birth, is remarkably long compared with other mammals of similar size. A tarsier, for example, gives birth to a single young after a gestational period of nearly six months. By contrast, a similarly sized rodent will often give birth to six or more young after the gestational period lasting just three weeks. Most primates usually give birth to a single baby, although some species, such as dwarf lemurs, usually have twins or triplets.
 Once the young are born, the period of parental feeding and protection can be even more drawn out. In small prosimians the young are often weaned after about five weeks, but in apes they are often fed on their mother's milk for three or four years, and they may continue to rely on her protection for six or more years. This long childhood - which reaches its extreme in humans - is a crucial feature of a primate's life because it enables complex patterns of behaviour to be passed on by learning.
 Some primates have fixed breeding seasons, but many can breed anytime of the year. In many species, females signal that they are in estrus - receptive and ready to mate - by releasing special scents. In other species, females develop conspicuous swelling around their genitals to signal their readiness for mating. Such swelling is especially noticeable in chimpanzees. While most copulation occurs when the females are receptive, in some species, such as humans and pygmy chimpanzees, copulation frequently occurs even if the female is not in estrus.
 Primates display a wide range of mating behaviours. Solitary primates, such as aye-ayes and orangutans, have simple reproductive behaviour. Within the territory that each male control, his imperative territorial rights are in assess of several females live, each with their own territory. The male mates with any females within his territory that are receptive. Other species, such as gibbons, form small family groups consisting of a monogamous pair and they’re young. Gorillas form harems, in which one adult male life with several adult females and they’re young. Among social primates, breeding can be complicated by the presence of many adults. Males may cooperate in defending their troop's territory, but they often fight each other for the chance to mate. In some species, only the dominant male mates with the females in the group. Chimpanzee females mate promiscuously with several adult males, although they usually pair up with one high-ranking male during the final few days of estrus, spending all of their time together and mating together exclusively.
 Primates have the most highly developed brains in the animal kingdom, rivalled only by those of dolphins, whales, and possibly elephants. Anthropoid primates in particular are intelligent and inquisitive animals that are quick to learn new patterns of behaviour. This resourcefulness enables them to exploit a wide range of foods and may help them to escape attacks by predators.
 Many zoologists believe that primates' large brains initially evolved in response to their tree-dwelling habits and their way of feeding. Anthropoid primates, which have the largest brains, live in a visual world, relying on sight to move about and to find and manipulate food. Unlike smell or hearing, vision generates a large amount of complex sensory information that has to be processed and stored. In primate brains, these operations are carried out by part of the brain called the cerebral cortex, which evolved into such a large structure that the rest of the brain is hidden beneath it. Some unrelated mammals, such as squirrels, also live in trees, but they have less-developed eyesight and much smaller brains.
 Increased brainpower has had important effects on the way primates live. It has helped them to move about and find food and enabled them to develop special skills. One of the most remarkable of these is Toolmaking, seen in chimpanzees and, to a far greater extent, in humans. Toolmaking, as opposed to simple tool use, involves a preconceived image of what the finished tool should look like - something that is only possible with an advanced brain.
 The intelligence of primates is also evident in their social behaviour. For species that live in groups, daily life involves countless interactions with relatives, allies, and rivals. Mutual cleaning and grooming of the fur, which removes parasites, helps to reinforce relationships, while threats
- sometimes followed by combat - maintain the hierarchy of dominance that permeates typical primate troops.
 Primates use a variety of methods to communicate. In solitary prosimians, when animals are not within sight of each other, communication is often accomplished by using scents. Such animals use urine, faeces, or special scent glands to mark territory or to show a readiness to mate. In social anthropoids, visual and vocal signals are much more important. Most monkeys and apes speak with a complex array of facial expressions, some of which are similar to the facial expressions used by humans.
 Primates also talk with a repertoire of sounds. These range from the soft clicks and grunts of the colobus to the songs of the gibbon and the roaring of the howler monkey, which can sometimes be heard more than 3 km. (2 mi.) away. Far-carrying calls are used in courtship, both to keep group members from getting separated and to mark and maintain feeding territories. Some primate utterances convey more precise messages, often denoting specific kinds of danger. In the wild, researchers have observed that chimpanzees run through as much as 34 different calls, and evidence suggests that they can pass on information-such as the location of food-using this form of communication.
 Comparatively, little in effect is known about the origins of primates compared with many other groups of mammals, because primates have left relatively few fossil remains. The chief reason for the scarcity of fossils is that forests, the primary home for most early primates, do not create good conditions for fossilization. Instead of being buried by sediment, the bodies of early primates were more likely to have been eaten by scavengers and their bones dispersed.
 The earliest fossils of primates discovered dates from the end of the Cretaceous Period, about 65 million years ago. These early fossils include specimens of a species called Notharctus, which resembles today's lemurs and had a long pointed snout. The ancestors of another prosimian group, the tarsiers, are known from fossils that date from the early Eocene Epoch, about 50 million years ago. In 1996 researchers in China recovered fossil bones of a primitive primate no bigger than a human thumb. The animal, named Eosimias, existed in as much as 45 million years ago. Many scientists believe that Eosimias is an example of a transitional animal in the evolution of prosimians to anthropoids.
 The origin of anthropoids has been difficult to pin down. A single anthropoid fossil has been found that may come from the Eocene Epoch, but conclusive fossil evidence of anthropoids does not appear until the Oligocene Epoch, which began 38 million years ago. These early anthropoids belonged to a lineage that led to the catarrhine primates - the Old World monkeys, apes, and humans. The platyrrhine primates, which include all New World monkeys, are presumed to have diverged from the Old World monkeys during the Eocene Epoch. They evolved in isolation on what was then the island continent of South America. Genetic analysis shows that New World monkeys clearly have the same ancestry with the catarrhines, which means that they must have reached the island continent from the Old World. Exactly how they did this is unclear. One possibility is that they floated across from Africa on logs or rafts of vegetation, journeying across an Atlantic Ocean that was much narrower than it is today.
 Of all primate groups, the apes are the direct ancestors of humans that bring on the most provocative of studies. One distinguishing query that finds of its vexation is that of two groups diverging. Based on the comparisons of genes and the structure of body parts, scientists think that the line leading to the orangutan diverged from the one leading to humans about 12 million years ago. The ancestral line leading to chimpanzees did not diverge until more recently, probably between five and seven million years ago. This evidence strongly suggests that chimpanzees are our closest living relatives.
 The word primate means "the first.” When it was originally coined more than two centuries ago, it conveyed the widely held idea that primates were superior to all other mammals. This notion has since been discarded, but nonhuman primates still generate great interest because of their humanlike characteristics.
 In scientific research, much of this interest has focussed on primate behaviour and its correspondence with human behaviour. Attempts have been made to train chimpanzees and orangutans to mimic human speech, but differences in anatomy make it very difficult for apes to produce recognizable words. A more revealing series of experiments has involved training chimpanzees, and later gorillas, to understand words and to respond using American Sign Language. In the late 1960s, a chimp named Washoe learned more than 130 signs. In the 1970s and 1980s, a gorilla named Koko learned to use more than 500 signs and to recognize an additional 500 signs. One outcome of these long-running experiments was that the chimps or gorillas occasionally produced new combinations of signs, suggesting that the animals were not simply repeating tricks that they had learned. More recently, chimps have been trained to talk with humans by using coloured shapes or computer keyboards. They too have shown an ability to associate abstract symbols with objects and ideas - the underlying basis of language.
 Apes and monkeys also play an important role in the field of medical research. Because their body systems work very much like our own, new vaccines and new forms of surgery are sometimes tried on apes and monkeys before they are approved for use on humans. Species that are most often used in this way include chimpanzees, baboons, and rhesus monkeys. This kind of animal experimentation has undoubtedly contributed to human welfare, but the medical use of primates is an increasingly controversial area, particularly when it involves animals captured in the wild.
 According to figures published by the World Conservation Union (IUCN), more than 110 species of primates - nearly half the world's total - are currently under threat of extinction. This makes the primates among the most vulnerable animals on earth.
 The species most under threats are those affected by deforestation. This has been particularly severe in Madagascar, the only home of the lemurs, and it is also taking place at a rapid rate in Southeast Asia, threatening gibbons and orangutans. The almost total destruction of Brazil's Atlantic rainforest has proved catastrophic for several species, including the lion tamarins, which are found only in this habitat. Primates are also threatened by collection for the pet trade and by hunting. Illegal hunting is the chief threat facing the mountain gorilla, a rare African subspecies that lives in the politically volatile border region straddling Uganda, Rwanda, and the Democratic Republic of the Congo.
 In the face of these threats, urgent action is currently underway to protect many of these endangered species. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) currently forbids the export of many primates, although not all countries have chosen to follow this law. More direct methods of species preservation include habitat protection and captive breeding programs. Sometimes - for example, the lion tamarin—these programs have met with considerable success. However, without the preservation of extensive and suitable natural habitats, many primate species are destined for extinction.
 Humans as primates, have themselves of a physical and genetic similarities showing that the modern human species, Homo sapiens, has a one and the same close relationship to another group of primate species, the apes. Humans and the so-called great apes (large apes) of Africa - chimpanzees (including bonobos, or so-called pygmy chimpanzees) and gorillas - have the same ancestor that lived sometime between eight million and six million years ago. The earliest humans evolved in Africa, and much of human evolution occurred on that continent. The fossils of early humans who lived between six million and two million years ago come entirely from Africa.
  Humans and great apes of Africa have the same ancestor that lived between eight million and five million years ago. Most scientists distinguish among 12 to 19 different species of early humans. Scientists do not all agree, however, about how the species are related or which ones simply died out. Many early human species - probably most of them - left no descendants. Scientists also debate over how to identify and classify particular species of early humans, and about what factors influenced the evolution and extinction of each species.
 The tree of Human Evolution Fossil evidence shows that the first humans evolved from ape ancestors at least six million years ago. Many species of humans followed, but only some left descendants on the branch leading to The Homo sapiens. In this slide show, white skulls represent species that lived during the period shown; gray skulls represent extinct human species.
 Early humans first migrated out of Africa into Asia probably between two million and 1.7 million years ago. They entered Europe much  later, generally within the past one million years. Species of modern humans populated many parts of the world much later. For instance, people first came to Australia probably within the past 60,000 years, and to the Americas within the past 35,000 years. The beginnings of agriculture and the rise of the first civilizations occurred within the past 10,000 years.
 The scientific study of human evolution is called Paleoanthropology. Paleoanthropology is a subfield of anthropology, the study of human culture, society, and biology. Paleoanthropologists search for the roots of human physical traits and behaviour. They seek to discover how evolution has shaped the potentials, tendencies, and limitations of all people. For many people, Paleoanthropology is an exciting scientific field because it illuminates the origins of the defining traits of the human species, and the fundamental connections between humans and other living organisms on Earth. Scientists have abundant evidence of human evolution from fossils, artifacts, and genetic studies. However, some people find the concept of human evolution troubling because it can seem to conflict with religious and other traditional beliefs about how people, other living things, and the world developed. Yet many people have come to reconcile such beliefs with the scientific evidence.
 Modern and Early Humans have undergone major anatomical changes during evolution. This illustration depicts Australopithecus afarensis, the earliest of the three species, the Homo erectus, an intermediate species, whereby the Homo sapiens, a modern human, and Homo’s ergaster. The modern humans are much taller than A. afarensis and have flatter faces and a considerable brawny brain. Modern humans have a larger brain than H. erectus and almost flat face beneath the front of the braincase.
 All species of organisms originate through the process of biological evolution. In this process, new species arise from a series of natural changes. In animals that reproduce sexually, including humans, the term species refers to a conjunctive organization into groups whose adult members regularly interbreed, resulting in fertile offsprings that are, offsprings themselves capable of reproducing. Scientists classify each species with a unique, but two-part scientific names. In this system, modern humans are classified as Homo sapiens.
 The mechanism for evolutionary change resides in genes—the basic units of heredity. Genes affect how the body and behaviour of an organism develop during its life. The information contained in genes can change - a process known as mutation. The way particular genes are expressed - how they affect the body or behaviour of an organism - can also change. Over time, genetic change can alter a species’s overall way of life, such as what it eats, how it grows, and where it can live.
 Genetic changes can improve the ability of organisms to survive, reproduce, and, in animals, raise offspring. This process is called adaptation. Parents pass adaptive genetic changes to their offspring, and ultimately these changes become common throughout a population - a group of organisms of the same species that share a particular local habitat. Many factors can favour new adaptations, but changes in the environment often play a role. Ancestral human species adapted to new environments as their genes changed, altering their anatomy (physical body structure), physiology (bodily functions, such as digestion), and behaviour. Over long periods, evolution dramatically transformed humans and their ways of life.
 Geneticists estimate that the human line began to diverge from that of the African apes between eight million and five million years ago (paleontologists have dated the earliest human fossils to at least six million years ago). This figure comes from comparing differences in the genetic makeup of humans and apes, and then calculating how long it probably took for those differences to develop. Using similar techniques and comparing the genetic variations among human populations around the world, scientists have calculated that all people may share common genetic ancestors that lived sometime between 290,000 and 130,000 years ago.
 Humans belong to the scientific order named Primates, a group of more than 230 species of mammals that also includes lemurs, lorises, tarsiers, monkeys, and apes. Modern humans, early humans, and other species of primates all have many similarities plus some important differences. Knowledge of these similarities and differences helps scientists to understand the roots of many human traits, and the significance of each step in human evolution.
 All primates, including humans, share at least part of a set of common characteristics that distinguish them from other mammals. Many of these characteristics evolved as adaptations for life in the trees, the environment in which earlier primates evolved. These include more reliance on sight than smell; overlapping fields of vision, allowing stereoscopic (three-dimensional) sight; limbs and hands adapted for clinging on, leaping from, and swinging on tree trunks and branches; the ability to grasp and manipulate small objects (using fingers with nails instead of claws); large brains in relation to body size; and complex social lives.
 The scientific classification of primates reflects evolutionary relationships between individual species and groups of species. Strepsirhini (meaning ‘turned-nosed’) primates - of which the living representatives include lemurs, lorises, and other groups of species all commonly known as prosimians - evolved earliest and are the most primitive forms of primates. The earliest monkeys and apes undergo an evolution from transmissiblel haplorhine (meaning ‘simple-nosed’) primates, of which the most primitive living representative is the tarsier. Humans evolved from ape ancestors.
 Tarsiers have traditionally been grouped with prosimians, but many scientists now recognize that tarsiers, monkeys, and apes share some distinct traits, and group the three together. Monkeys, apes, and humans - who share many traits not found in other primates -together make up the suborder Anthropoidea. Apes and humans collectively carry out the superfamily of the Hominoidea, a grouping that emphasizes the close relationship among the species of these two groups.
 Paleoanthropologists Donald C. Johanson of the Cleveland Museum of Natural History and Tim D. White of the University of California, Berkeley, announced that in January the discovery of the most ancient Hominid (humanlike) species yet uncovered, which they have named Australopithecus afarensis. The fossils on which they base this claim are about three million to four million years old and were found during the 1970's at two widely separated localities in East Africa. The majority were collected at Hadar, a remote region of the Afar Depression of Ethiopia, by Johanson; the others were uncovered in northern Tanzania at Laetolil, 30 miles south of Olduvai Gorge, by anthropologist Mary Leakey. The Hadar material consists of bones from at least 35 individuals and includes the best preserved australopithecine skeleton yet found. Nicknamed "Lucy" by Johanson, this skeleton is about 40 percent complete and is evidently of a female who stood about 3.5-4 feet tall and lived some three million years ago. The Laetolil fossils, closer to four million years old, are astonishingly similar in many ways to the Hadar material. Because of the remarkable completeness and good preservation of both fossil collections, we are afforded a previously unavailable glimpse of early human evolution. Analysis suggests that these creatures had rather small brains, no larger than those of the gorilla, but the leg and pelvic bones clearly indicate that A. afarensis walked on two legs like humans. In these respects the newly described fossils do not differ substantially from previously described australopithecine species, which date from about 1.5 million to 2.5 million years ago. All previously recognized hominids, however, show larger cheek teeth (molars) and smaller front teeth (incisors and canines) than the apes. A. afarensis, in contrast, shows very broad incisors and large, projecting canines, to some degree more like those of an apes. The appearance of such primitive dental characteristics in an australopithecine has profound implications for evolutionary history. The most widely held theory states that the evolutionary lines leading to modern humans and apes diverged some 12 million to 15 million years ago, when apes from which humans are descended moved out of the trees and began to exploit the resources of open grasslands for food. This change in habitats is thought to have produced the characteristic humanlike denotation, which is more efficient at chewing tough food, such as seeds, roots, and tubers, than is the denotation of the apes. Fossil teeth and jaws of a human type characterize a creature called Ramapithecus, which lived around ten million years ago and is generally considered a human ancestor. However, the primitive, more primordial apes of A. afarensis have now cast doubt on the status of Ramapithecus as an ancestral hominid and made unclear the ultimate reason for the differentiation of human ancestors from the apes.
 Researchers in South Africa having discovered what they believe are the oldest and best-preserved skulls and skeletons of one of humanity's earliest ancestors, according to a report published in the December 9, 1998, publication of The South African Journal of Science. Paleontologists said the fossilized remains would exceedingly be every bit as two million years older than the oldest previously known complete hominid skeletons. The new finding is expected to reveal much about the anatomy and evolution of early humans, and may rank among the most important breakthroughs in Paleoanthropology (the archaeological study of early human evolution).“It is one of many key elements from ape to man,” said Ronald J. Clarke, a paleoanthropologists at the University of Witwatersrand in Johannesburg, South Africa, who led the team that made the discovery. The skeleton was discovered in the fossil-rich vicinitized near the Sterkfontein Caves, near Krugersdorp in northeastern South Africa. The skeleton is of a small, adult hominid who was about 1.2-m (4-ft) tall and weighed about 32 k. (70 lb.). Clarke's team dated the bones at 3.2 million to 3.6 million years old.
 The bones are believed to belong to a species of australopithecine, an early hominid that had human and apelike features. However, most of the bones remain embedded in rock within the cave.  Paleontologists may be accredited for being as far as possible and study of anatomical skeletons until it is removed, a process that Clarke said could take a year or longer. Clarke made the discovery after unexpectedly finding four hominid foot bones in a box of unsorted fossils at the university in 1994.  Another search of boxes in a university storage room in May 1997 revealed more foot and lower leg bones. To Clarke's astonishment, all of the bones appeared to belong to the same hominid.
 Clarke's initial discovery, announced in 1995, added new evidence to a longstanding debate among anthropologists about the path of early hominid development. Clarke and several of his colleagues argued that the bones of the specimen, dubbed Little Foot, reflected a transition from four-legged tree dwellers to two-legged creatures capable of walking upright. In particular, Clarke said the specimen's humanlike ankles and grasping, an apelike big toe suggested that the creature was a capable tree climber who could easily walk on two legs. Other anthropologists dismissed the idea, however, asserting that humans evolved from plains-dwelling hominids and did not live in trees.
 After finding additional bones in 1997, Clarke believed that the rest of the skeleton might be present in Sterkfontein's Silberberg Grotto, where the bones had been originally excavated. Within days of searching, his assistants discovered a piece of fossilized bone protruding from the cave wall that perfectly matched one of Clarke's fossil fragments. Although the excavation is at a preliminary stage, Clarke said the remainder of the skeleton might be present and intact, laying face downward in limestone.
 Before Clarke's find, the most comprehensive australopithecine skeleton was an Australopithecus afarensis specimen known as Lucy, discovered by anthropologist Donald Johanson in Ethiopia in 1974 and dated at 3.2 million years old. Lucy, however, is only about 40 percent complete. The oldest known complete hominid skeleton was a species of Homo erectus found in Kenya and dated at 1.5 million years old.
 The new discovery is considered extraordinary because the fossil record of early hominids is so fragmentary. Paleontologists have had to piece together knowledge about ancient human species by using bone fragments derived from many individuals, making generalizations about anatomy difficult. Once the bones have been chipped from the grotto rock, scientists will examine the hips and legs to determine whether or not the creature could easily climb trees. In addition, they hope skeletal features will give them clues about the specimen's sex and how these early hominids lived, including their likely diet and possible foraging behaviours.
 Scientists also believe the skeleton's intact skull could shed light on another key puzzle of early human evolution: the relation between a brain size and upright locomotion. Many experts believe that it was the ability to walk on two legs - rather than brain size or use of tools - that set the human lineage apart from all other primates
 Another mystery scientists will explore is whether the fossils represent either an example of Australopithecus afarensis (like Lucy), of a southern African hominid species, known as Australopithecus africanus, or possibly a new species together. If the species is unrelated to Lucy and is older, then it could force anthropologists to reconsider their views about hominid evolution in Africa. Because of Lucy's age, many scientists now believe that A. afarensis is a common ancestor to all succeeding australopithecine species.
 Nevertheless, some paleontologists cautioned that the age of the new find had not yet been conclusively established and could be only about two million year’s old. The most accurate forms of dating require the presence of volcanic ash, which contains radioactive elements that decay in a predicable manner. No such material was present in the cave.
 To date the skeleton, Clarke and his team finds distinctive animal fossils near the hominid remains. The age of these animal fossils had already been determined at other datable sites. This technique is not foolproof, however, because movements in the rock layers could make fossils from animals that did not coexist appear next to each other, experts said.
 Yet, Spanish paleoanthropologists recently described the fossil remains of several human ancestors from the last Ice Age that were found at a cave site in northern Spain. Did their findings identify a distinct human ancestral species, as the Spaniards suggested? The debate over the paths of human evolution continued as new findings about Human ancestors came of  Spanish paleoanthropologists, and  have added to the complexity of theories about early humans in Europe with their recent description of the fossil remains of several Ice Age human ancestors found in northern Spain. The researchers suggested that these early humans, who lived more than 780,000 years ago, may have been a separate species that preceded both modern humans and the now-extinct early humans known as Neanderthals.
 The researchers said that among the fossils were the facial bones of a boy showing both primitive and modern features and identifying these human ancestors as a distinct species. They suggested the name Homo’s antecessor for the proposed new species. Spanish paleoanthropologists José Bermúdez de Castro of the National Museum of Natural Sciences in Madrid, Spain, and his colleagues described the fossils in the May 30, 1997, issues of the Journal Science.
 Although anthropologists agreed that the fossil find was very important, most were not ready to accept the ancient humans as representing a new species. Anthropologists pointed out that not only are the dental and facial bones of a boy scant evidence on which to identify a new species, but also there is a chance that some of the boy's features were in an intermediate stage that would have changed when the boy reached adulthood. The Spanish researchers' proposed path of human evolution also was controversial, because it pushes groups of early humans off the direct line leading to modern humans, suggesting that there may have been more dead ends in human evolution than previously thought.
 The Spanish scientists first reported finding this group of fossils, the oldest remains of prehumans ever found in Europe, in August 1995. Previously the oldest known Europeans were a group of early humans sometimes classified as a separate species, Homo heidelbergensis. The earliest known specimens from this group date from roughly 500,000 years ago. Using a technique known as Paleomagnetic analysis, the Spanish researchers dated the fossil remains found recently in northern Spain to at least 780,000 years ago, in the Pleistocene Epoch.
 Paleomagnetic dating is because the direction of the earth's geomagnetic field has reversed often during the history of the world. The dates of these irregular reversals in geomagnetic polarity have been well documented. Currently the geomagnetic polarity of the earth is facing north, but less than a million years ago it faced south. Internal magnetic traces in the layers of rock that lay the groundwork for nearby fossils shown that the fossils had been buried before the earth's magnetic field last switched direction, from south to north, 780,000 years ago.
 The Spanish paleoanthropologists found more than 80 fossils representing at least six individuals, including both juveniles and adults. The fossils were found in a deep pit at a cave site known as Gran Dolina, in the Atapuerca Mountains near the city of Burgos in northern Spain.
 The picture of early human residence in Europe is unclear at best. Anthropologists agree that hominids - a family of bipedal primates that includes modern human beings and all extinct species of early humans - have their origins in Africa. The Spanish anthropologists speculated that the early humans they called Homo antecessor may have first evolved in Africa from a primitive human classified by some paleoanthropologists as Homo ergaster and by others as early Homo erectus and that Homo sapiens developed from Homo antecessor in Africa. The researchers further proposed that Homo antecessor migrated to Europe, and that Homo heidelbergensis and then Neanderthals (also called Homo sapiens neanderthals) evolved from this line.
 Under this proposed set of relationships, Homo heidelbergensis would not be a common ancestor of Homo sapiens and Neanderthals, as currently believed by many anthropologists. The Spanish anthropologists' model also pushes forward the later members of the Homo erectus, perhaps in a direct inclination away from their evolving lineage leading face-to-face to modern human beings. An early Homo erectus appeared about 1.9 million to two million years ago in Africa, and more recent examples of this early human have been found in China and Java, Indonesia. In the Spanish scientists' proposed model, Asian members of
A Homo erectus become a side path on human evolution, rather than an intermediate step between Homo ergaster and Homo heidelbergensis.
 The human family tree has usually become less linear and more complex over the past decade as anthropologists have made more discoveries.
 Archaeological study covers an extremely long span of time and a great variety of subjects. The earliest subjects of archaeological study date from the origins of humanity. These include fossil remains believed to be of human ancestors who lived 3.5 million to 4.5 million years ago. The earliest archaeological sites include those at Hadar, Ethiopia, Olduvai Gorge and Laetoli, Tanzania, East Turkana, Kenya, and in a balanced significance in East Africa. These sites contain evidence of the first appearance of bipedal (upright-walking), apelike early humans. Laetoli even reveals footprints of humans from 3.6 million years ago. Some sites also contain evidence of the earliest use of simple tools. Archaeologists have also recorded how primitive forms of humans spread out of Africa into Asia about 1.8 million years ago, then into Europe about 900,000 years ago.
 The first physically modern humans, The Homo sapiens, appeared in tropical Africa between 200,000 and 150,000 years ago - dates determined by molecular biologists and archaeologists working together. Dozens of archaeological sites throughout Asia and Europe show how people migrated from Africa and settled these two continents during the last Ice Age (100,000 to 15,000 years ago). Archaeological studies have also provided much information about the people who first arrived in the Americas more than 12,000 years ago.
 In their search for the original cradle of humanity, anthropologists have long been looking for remains of early man in all corners of the world. In this effort they have eliminated the Americas and Australia from the competition and to convey the honour of having seen man's first emergence to either Africa or Asia. Any find of early man made in these areas takes on, therefore, a particular importance. In 1953 fragments of a human skull without the face were discovered in probably late Pleistocene levels near Hopefield, 76 miles north of Capetown, Africa, close to Saldanha Bay. This Saldanha skull is very big and low, has a strongly receding forehead, tremendous bone ridges across the eyebrows, and its bones are extremely thick. All these features are typical of the most primitive types of early man. Probably the most significant fact is that this new specimen resembles very closely the famous Rhodesian Man known, from a skull found in late Pleistocene levels at Broken Hill in 1921. This Rhodesian lowbrow is one of the most puzzling finds of early man ever made, for he combines certain extremely primitive characteristics with some very modern features. He has enormous brow ridges, the heaviest ever found in any type of early man, a very strongly projecting face and unusually broad palate, a strongly receding forehead, and low cranial vaults. Still, his large skull has a brain volume within the range of recent man, and in spite of the various primitive features, he suffered from a truly modern disease: tooth decay. This plague of modern humans appears in the Neolithic, the period in which pottery was discovered and in which man began to boil his food. Every dentist will tell you that soft food is the greatest enemy of teeth, and thus the boiling of food instead of the earlier roasting caused the frequent occurrence of tooth decay in the Neolithic period. Nevertheless, the Rhodesian Man must have been an unfortunate creature indeed; for apart from the dubious honour of being the first man who needed a dentist, he suffered from mastoiditis and rheumatism, as appears from a careful inspection of his skull and his tibia. To top it all, Sir Arthur Keith, Britain's most distinguished anthropologist, suggests that this truly sick man suffered from acromegaly, a disease of overgrowth of the head, feet, and hands. Although such a diagnosis has previously been doubted on certain grounds, it is the merit of Saldanha man of really absolving his Rhodesian cousin from at least this latter verdict and saving his face  - or rather brain. Since both skulls resemble each other so closely, the large size of the skull and the enormous orbital ridges can no longer be considered as pathological features but must are typical of early man in Africa.
 Fossils suggest that he evolutionary line leading to us had achieved an upright posture by around four million years ago, then began to increase in body size and a relative brain size of around 2.5 million years ago. That protohuman generally brought into a different state of awareness the fact that Australopithecus africanus, Homo habilis and Homo erectus, their apparent evolution into each other by some chronological succession. Although the Homo erectus, the stage reached around 1.7 million years ago, was close to us modern humans in body size, its brain size, but still barely half of ours. Stone tools became common around 2.5 million years ago, but they were merely the crudest of flaked or battered stones. In zoological significance and distinctiveness, The Homo erectus was more than an ape, but still much less than a modern human.
 Since the biological regularities of living organisms display an active and intimate engagement with their environment that is categorically different from that of inorganic matter, we can conclude that they represent profound oppositions. Since organic and inorganic matter are constructs that cannot be applied simultaneously in the same situation and yet are both required for a complete description of the situation, they must be as be viewed in compliments. In that, given the lawful regularities displayed by organic and inorganic matter are different. A profound complementary relationship exists between the law of physics and that of biology. For example, a complete description in mathematical physics of all the mechanisms of a DNA molecule would not be a complete description of organic matter for an obvious reason. The quality of life associated with the known mechanism of DNA replication exists except an objectivised description. It seems likened to the seamless web of interactions under which the organism holds with its environment, only to suggest that the laws of nature have accorded for biological regularities. Additionally, as it seems agreed to the behaviours we associate with life, which are not merely those of mathematical physics. Even if we could replicate all of the fundamental mechanisms of biological life by manipulating inorganic matter in the laboratory, this problem would remain. To prove that no laws other than those of mathematical physics are involved, that if we would be obliged to create life without any interaction with an environment in which the life form sustains itself or interacts.
 Although most physical scientists probably assume that the mechanism of biological life can be completely explained following the law of mathematical physics, many phenomena associated with life cannot be explained in these terms. For example, the apparent compulsion of individual organisms to perpetuate their gene, ‘selfish’ or not, is obviously a dynamic of biological regularities that is not apparent in an isolated system. This contributive functional dynamic cannot be described as for the biochemical mechanisms of DNA or any other aspect of isolated organic matter. The specific evolutionary path followed by living organisms is unique and cannot be completely described as based on prior applications of the laws of physics.
 The more complex organisms that evolve from a symbiotic union that is sometimes called in biology texts factories or machines, but, nonetheless, a machine, as Darwin’s model for the relationship part and whole suggest, is a unity of order and not of substance, and the order that exist in a machine is external to the parts. As the biologist Paul Weiss has pointed out, however, the part-whole relationship that exists within and between cells in complex life forms is not that of a machine.
 The whole within the part that sets the boundary conditions of cells is DNA, and a complete strand of the master molecule of life exists in the nucleus of each cell. DNA evolved in an unbroken sequence from the earliest life form, and the evolution of even the most complex life forms cannot be separated from the co-evolution of microbial ancestors. DNA in the average cell codes for the production of about two thousand different enzymes, and each of these enzymes canalizes a particular chemical reaction. The boundary conditions within each cell resonate with the boundary condition of all other cells and maintain the integrity of uniqueness of whole organisms.
 Volution, in biology, defines a complex process by which the characteristics of living organisms change over many generations as traits are passed from one generation to the next. The science of evolution seeks to understand the biological forces that caused ancient organisms to develop into the tremendous and ever-changing variety of life seen on Earth today. It addresses how, over a time, various plant and animal species branch off to become entirely new species, and how different species are related through complicated family trees those span millions of years.
 Evolution provides an essential framework for studying the ongoing history of life on Earth. A central, and historically controversial, component of evolutionary theory is that all living organisms, from microscopic bacteria to plants, insects, birds, and mammals, have the same ancestor. Species that are closely related share a recent common ancestor, while distantly related species have a common ancestor further in the past. The animal most closely related to humans, for example, is the chimpanzee. The common ancestor of humans and chimpanzees is believed to have lived approximately six million to seven million years ago. On the other hand, an ancestor common to humans and reptiles that had existed of some 300 million years ago, as these common ancestors were more distantly related forms that lived even farther in the past. Evolutionary biologists attempt to figure out the history of lineages as they diverge and how differences in characteristics developed over time.
 Throughout history, philosophers, religious thinkers, and scientists have attempted to explain the history and variety of life on Earth. During the rise of modern science in western Europe in the 17th and 18th centuries, a predominant view held that God created every organism on Earth almost as it now exists. However, in that time of burgeoning interest in the study of apes and natural history, the beginnings of a modern evolutionary theory began to take shape. Early evolutionary theorists proposed that all of the life on Earth evolved gradually from simple organisms. Their knowledge of science was incomplete, however, and their theories left too many questions unanswered. Most prominent scientists of the day remained convinced that the variety of life on Earth could only result from an act of divine creation.
 In the mid-19th century a modern theory of evolution took hold, thanks to British naturalist Charles Darwin. In his book, On the Origin of Species by Means of Natural Selection, Darwin described the evolution of life as a process of natural selection. Life, he suggested, is a competitive struggle to survive, often in the face of limited resources. Living things must compete for food and space. They must evade the ravages of predators and disease while dealing with unpredictable shifts in their environment, such as changes in the climate. Darwin offered that, within a given population in a given environment, certain individuals possess characteristics that make them more likely to survive and reproduce. These individuals will pass these critical characteristics onto their offspring. The number of organisms with these traits increases as each generation passes on the advantageous combination of traits. Out matched, individuals lacking the beneficial traits gradually decrease in number. Slowly, Darwin argued, natural selection tips the balance in a population toward those with the combination of traits, or adaptations, best fitted in with their environment.
 While, On the Origin of Species were an instant sensation and best sellers, Darwin’s theories faced hostile reception by critics giving further information of those railed against his blasphemous ideas. Other critics pointed to questions left unresolved by Darwin’s careful arguments. For instance, Darwin could not explain the mechanism that caused life forms to change from generation to generation.
 Hostility gave to a considerable degree the acclaim as scientists vigorously debated, explored, and built on Darwin’s theory of natural selection. As the 20th century unfolded, scientific advances revealed the detailed mechanisms missing from Darwin’s theory. Study of the complex chemistry of all organisms unveiled the structure of genes and how they are duplicated, altered, and passed from generation to generation. New statistical methods helped explain how genes in specific populations change over generations. These new methods provided insight into how populations remain adaptable to changing environmental circumstances and broadened our understanding of the genetic structure of populations. Advances in techniques used to find out the age of fossils provided clues about when extinct organisms existed and details about the circumstances surrounding their extinction. New molecular biology techniques compare the genetic structures of different species, enabling scientists to find specific undetectable evolutionary relationships between species. Today, evolution is recognized as the cornerstone of modern biology. Uniting such diverse scientific fields as cell biology, genetics, palaeontology, and even geology and statistics, the study of evolution reveals an exquisitely complex interaction of the forces that act upon every life form on Earth.
 Natural selection is tied to traits that organisms pass from one generation to the next. In humans, these traits include hundreds of features such as eye colour, blood type, and height. Nature offers countless other examples of traits in living things, such as the pattern on a butterfly’s wings, the markings on a snail’s shell, the shape of a bird’s beak, or the colour of a flower’s petals.
 Such traits are controlled by specific bits of biochemical instructions known as genes. Genes are composed of individual segments of the long, coiled molecule called deoxyribonucleic acid (DNA). They direct the synthesis of proteins, molecular labourers that serve as the constructive edifices to all building blocks of cells, control chemical reactions, and transport materials to and from cells. Proteins are themselves composed of long chains of amino acids, and the biochemical instructions found in DNA determine the arrangement of amino acids in a chain. The specific sequence of amino acids dictates the structure and resulting function of each protein.
 All genetic traits result from different combinations of gene pairs, one gene inherited from the mother and one from the father. Each trait is thus represented by two genes, often in different forms. Different forms of the same gene are called alleles. Traits depend on very precise rules governing how genetic units are expressed through generations. According to the laws governing heredity, when a dominant allele (say, tongue rolling) and a recessive allele (no tongue rolling) combines, the trait will always be dictated by the dominant allele. The no tongue rolling trait, or any other recessive trait, will only occur in an individual introduced by those sustaining of getting hold of the two recessive alleles.
 Evolutionary change takes place in populations over many generations. Since individual organisms cannot evolve in a single lifetime, evolutionary science focuses on a population of interbreeding individuals. All populations contain some variations in traits. In humans, for example, some people are tall, some are short, and some are of medium height.
 In interbreeding populations, genes are randomly shuffled among members of the population through sexual reproduction, the process that produces genetically unique offspring. Individuals of different sexes develop specialized sex cells called gametes. In humans and other vertebrates (animals with backbones), these gametes are sperm in males and eggs in females. When males and females mate, these sex cells join in fertilization. A series of cell divisions creates individuals with a unique assembly of genes. No individual members of any population (except identical twins, which develop from a single egg) are alike in their genetic makeup. This diversity, called genetic diversity or variation, is essential to evolution. The greater a population’s genetic diversity, the more likely it is to evolve specific traits that enable it to adapt to new environmental pressures, such as climate change or disease. Expressing of some time, an expressing eventful place showing of a distinction of contrast of such pressures might drive a population with a low degree of genetic diversity to extinction.
 Sexual reproduction ensures that the genes in a population are rearranged in each generation, a process termed recombination. Although the contributive combinations of genes in individuals change with each new generation, the gene frequency, or ratio of different alleles in the entire population, remains constant if no evolutionary forces act on the population. One such force is the introduction of new genes into the genetic material of the population, or gene pool.
 When individuals move between one population and another, new genes may be introduced to populations. This phenomenon, known as gene flow, results from chance dispersal and intentional migration. Take, for example, two populations of related wildflowers, one red and one white, separated by a large tract of land. Under normal circumstances, the two groups do not interbreed because the wind does not blow hard enough to carry pollen between the populations so that pollination can occur. If in agreement that it happens of an unusually strong wind that carries pollen from the red wildflower population to the white wildflower population, the gene for red flowers may be introduced to the white population’s gene pool.
 Genes themselves are constantly being modified through a process called mutation: a change in the structure of the DNA in an individual's cells. Mutations can occur during replication, the process in which a cell splits itself into two identical copies known as daughter cells. Normally each daughter cell receives an exact copy of the DNA from the parent cell. Occasionally, however, errors occur, resulting in a change in the gene. Such a change may affect the protein that the gene produces and, ultimately, change an individual’s traits. While some mutations occur spontaneously, others are caused by factors in the environment, known as mutagens. Examples of mutagens that affect human DNA include ultraviolet light, X rays, and various chemicals.
 Whatever their cause, mutations are a rare but slow and continuous sources of new genes in a gene pool, yet mutations are neutral - that is, they have no effect. Other mutations are detrimental to life, causing the immediate death of any organism that inherits them. Once in a great while, however, a mutation gives an organism an advantageous trait. A single organism with an advantageous trait is only half of the equation, however. For evolution to occur, the forces of natural selection must distribute that trait to other members of a population.
 Natural selection sorts out the useful changes in the gene pool. When this happens, populations evolve. Beneficial new genes quickly spread through a population because members who carry them have a greater reproductive success, or evolutionary fitness, and consequently pass the beneficial genes to more offspring. Conversely, genes that are not as good for an organism are eliminated from the population, sometimes quickly and sometimes more gradually, depending on the severity of the gene, because the individuals who carry them do not survive and reproduce with individuals without the bad gene. Over several generations, the gene and most of its carriers are eliminated from the population. Severely detrimental genes may persist at very low levels in a population, however, because they can be reintroduced each generation by mutation.
 Natural selection only allows organisms to adapt to their current environment. Should environmental conditions change, new traits may prevail. Moreover, natural selection does not always favour a single version of a trait. Occasionally, multiple versions of the same trait may instill their carriers with equal evolutionary benefit. Nor does natural selection always favour change. If environmental conditions so dictate, natural selection remains unchanged by eliminating extreme versions of a particular trait from the population.
 Often, shifts in environmental conditions, such as climate change or the presence of a new disease or predator, can push a population toward one extreme for a trait. In periods of prolonged cold temperatures, for example, natural selection may favour larger animals because they are better able to withstand extreme temperatures. This mode of natural selection, known as directional selection, is evident in cheetahs. About four million years ago, cheetahs were more than twice as heavy as modern cheetahs. Still, quicker and lighter members of the population had greater reproductive success than did larger members of the population. Over time, natural selection takes to be smaller and smaller cheetahs.
 Sometimes natural selection acts to preserve the status quo by favouring the intermediate version of a characteristic instead of one of two extremes. An example of this selective force, known as stabilizing selection, was evident in a study of the birth weight of human babies published in the middle of the 20th century. It showed that babies of intermediate weight, about 3.5 kg. (8 lb.), was more likely to survive. Babies with a heftier birth weight had lower chances for survival because they were more likely to cause complications during the delivery process, and lightweight babies were often born premature or with other health problems. Babies of intermediate birth weight, then, were more likely to survive to reproductive age.
 Occasionally natural selection favours two extremes, causing alleles for intermediate forms of a trait to become less common in the gene pool. The African Mocker swallowtail butterfly has undergone this form of selection, known as disruptive selection. The Mocker swallowtail evades its predators by resembling poisonous butterflies in its ecosystem. Predators have learned to avoid these poisonous butterflies and to steer away from the look alike Mocker swallowtails. The Mocker swallowtail has a large range, and in different regions, the Mocker swallowtail looks very different, depending on which species of poisonous butterfly it mimics. In some areas the butterfly displays black markings on a white background; in others the markings float on an orange background. Since a Mocker swallowtail appears poisonous to predators, it has a greater chance of survival and therefore a higher evolutionary fitness. Mocker swallowtails that do not look poisonous have a much lower evolutionary fitness because predators quickly eat them. Disruptive selection, then, favours the extreme colour patterns of white or orange, and nothing between.
 In many species, sexual selection results in an accompaniment to the male with elaborate features. Many male birds, such as peacocks, have colourful and showy plumage. Male fiddler crabs have one greatly enlarged claw, and large skin flaps frame the face of the male frilled lizards. Exuberantly some species, males dance elaborate courtship dances designed to display the males’ virility and physical fitness.
 Many such traits are a liability to survival, making them counter to the principles of natural selection. For instance, bright colouration and elaborate courtship dances draw the attention of predators. The fiddler crab’s large claw is cumbersome, as are the frilled lizard’s skin flaps. The huge tail feathers of the male peacock give it an awkward, bumbling gait. All these features undoubtedly slow the animals, making them less capable of evading predators or securing prey. Nevertheless, the increased reproductive success these showy characteristics instill makes them worth the risk.
 Natural selection is not the only force that changes the ratio of alleles present in a population. Sometimes the frequency of particular alleles may be altered drastically by chance alone. This phenomenon, known as genetic drift, can cause the loss of an allele in a population, even if the allele leads to greater evolutionary fitness. Conversely, genetic drift can cause an allele to become fixed in a population, that is the allele can be found in every member of the population, even if the allele decreases fitness.
 Although any population can fall victim to genetic drift, small populations are more vulnerable than larger populations. Imagine a particular allele is present in 25 percent of a population of worms. If a flood occurs and randomly eliminates half the population, the laws of probability predict that approximately 25 percent of the surviving population will carry the allele. In a population of 120,000 worms, this means that about 15,000 of the surviving 60,000 worms will carry the allele. Even if, by chance, the flood claimed the lives of an additional 10 percent of the carriers, thousands of copies of the allele would remain in the population. Still, in a population of only 12 worms, the laws of probability predict that only 1.5 of the surviving six worms would carry the allele. If, by chance, the flood claimed more of the carriers of the allele than the non-carriers, the allele could be eliminated.
 The hypothetical flood created what is called a population bottleneck. It reduced the genetic variation in the smaller population such that, even if the group’s number again reached 12 members, its genetic diversity might very well be lower than the genetic diversity of the original population. All of the descendants came from just a few surviving individuals, who carried just a fraction of the alleles present in the former population. Likewise, when a few individuals leave a large population and establish a new one, they bring only a fraction of the genetic diversity of the original population with them. Any descendants of the founding members face the possibility of a drastically reduced genetic diversity. An example of this principle, known as the founder effect, is evident in the Amish community in Pennsylvania. All of the people in this community are descendants of about 200 individuals who established the community after leaving Europe in the early 1700s. One of these founders carried an unusual allele that causes a rare kind of dwarfism. As a result, in the Pennsylvania Amish community today the frequency of this rare allele is one in 14 individuals. In the general population this allele appears in one in 1,000 individuals.
 The forces of natural selection and genetic drift continuously influence and change the characteristics of a population. However, most often these forces are not sufficient to create an entirely new species. Different species arise when, for one reason or another, members of a population cease to interbreed. When something prevents populations from mating, they are said to be reproductively isolated from one another. Two reproductively isolated populations cannot randomly exchange genetic material with each other, and as a result, the groups diverge as they evolve independently of one another. In this process, called speciation, the members of each group become so different that they can no longer successfully interbreed. At this point, a new species has formed.
 Interbreeding normally continues if a time or goal holds of what might especially be a place where nothing is to stop it. Anything that hinders interbreeding is called an isolating mechanism. Geographic barriers isolate populations, leading to the formation of entirely new species in a process called allopatric speciation. Less frequently, mutations or subtle changes in behaviour prevent individuals living in close proximity from reproducing. This may lead to sympatric speciation, in which two distinct subgroups of a population cease exchanging genetic material and evolve into two or more distinct species.