Paleolithic

The Paleolithic or Palaeolithic (c. 3.3 million – c. 11,700 years ago) (/ˌpeɪlioʊˈlɪθɪk, ˌpæli-/ ^ⓘ PAY-lee-oh-LITH-ik, PAL-ee-), also called the Old Stone Age (from Ancient Greek παλαιός (palaiós) 'old' and λίθος (líthos) 'stone'), is a period in human prehistory that is distinguished by the original development of stone tools, and which represents almost the entire period of human prehistoric technology. It extends from the earliest known use of stone tools by hominins, c. 3.3 million years ago, to the end of the Pleistocene, c. 11,650 cal BP.^[1]

The Paleolithic Age in Europe preceded the Mesolithic Age, although the date of the transition varies geographically by several thousand years. During the Paleolithic Age, hominins grouped together in small societies such as bands and subsisted by gathering plants, fishing, and hunting or scavenging wild animals.^[2] The Paleolithic Age is characterized by the use of knapped stone tools,^{[not verified in body]} although at the time humans also used wood and bone tools. Other organic commodities were adapted for use as tools, including leather and vegetable fibers; however, due to rapid decomposition, these have not survived to any great degree.

About 50,000 years ago, a marked increase in the diversity of artifacts occurred. In Africa, bone artifacts and the first art appear in the archaeological record. The first evidence of human fishing is also noted, from artifacts in places such as Blombos Cave in South Africa. Archaeologists classify artifacts of the last 50,000 years into many different categories, such as projectile points, engraving tools, sharp knife blades, and drilling and piercing tools.

Humankind gradually evolved from early members of the genus Homo—such as Homo habilis, who used simple stone tools—into anatomically modern humans as well as behaviourally modern humans by the Upper Paleolithic.^[3] During the end of the Paleolithic Age, specifically the Middle or Upper Paleolithic Age, humans began to produce the earliest works of art and to engage in religious or spiritual behavior such as burial and ritual.^{[4][page needed][5][need quotation to verify]} Conditions during the Paleolithic Age went through a set of glacial and interglacial periods in which the climate periodically fluctuated between warm and cool temperatures.

By c. 50,000 – c. 40,000 BP, the first humans set foot in Australia. By c. 45,000 BP, humans lived at 61°N latitude in Europe.^[6] By c. 30,000 BP, Japan was reached, and by c. 27,000 BP humans were present in Siberia, above the Arctic Circle.^[6] By the end of the Upper Paleolithic Age humans had crossed Beringia and expanded throughout the Americas continents.^[7][8]

The term "Palaeolithic" was coined by archaeologist John Lubbock in 1865.^[9] It derives from Greek: παλαιός, palaios, "old"; and λίθος, lithos, "stone", meaning "old age of the stone" or "Old Stone Age".

The Paleolithic overlaps with the Pleistocene epoch of geologic time. Both ended 12,000 years ago although the Pleistocene started 2.6 million years ago, 700,000 years after the Paleolithic's start.^[10] This epoch experienced important geographic and climatic changes that affected human societies.

During the preceding Pliocene, continents had continued to drift from possibly as far as 250 km (160 mi) from their present locations to positions only 70 km (43 mi) from their current location. South America became linked to North America through the Isthmus of Panama, bringing a nearly complete end to South America's distinctive marsupial fauna. The formation of the isthmus had major consequences on global temperatures, because warm equatorial ocean currents were cut off, and the cold Arctic and Antarctic waters lowered temperatures in the now-isolated Atlantic Ocean.

Most of Central America formed during the Pliocene to connect the continents of North and South America, allowing fauna from these continents to leave their native habitats and colonize new areas.^[11] Africa's collision with Asia created the Mediterranean, cutting off the remnants of the Tethys Ocean. During the Pleistocene, the continents were essentially at their modern positions; the tectonic plates on which they sit have probably moved at most 100 km (62 mi) from each other since the beginning of the period.^[12]

Climates during the Pliocene became cooler and drier, and seasonal, similar to modern climates. Ice sheets grew on Antarctica. The formation of an Arctic ice cap around 3 million years ago is signaled by an abrupt shift in oxygen isotope ratios and ice-rafted cobbles in the North Atlantic and North Pacific Ocean beds.^[13] Mid-latitude glaciation probably began before the end of the epoch. The global cooling that occurred during the Pliocene may have spurred on the disappearance of forests and the spread of grasslands and savannas.^[11]

The Pleistocene climate was characterized by repeated glacial cycles during which continental glaciers pushed to the 40th parallel in some places. Four major glacial events have been identified, as well as many minor intervening events. A major event is a general glacial excursion, termed a "glacial". Glacials are separated by "interglacials". During a glacial, the glacier experiences minor advances and retreats. The minor excursion is a "stadial"; times between stadials are "interstadials". Each glacial advance tied up huge volumes of water in continental ice sheets 1,500–3,000 m (4,900–9,800 ft) deep, resulting in temporary sea level drops of 100 m (330 ft) or more over the entire surface of the Earth. During interglacial times, drowned coastlines were common, mitigated by isostatic or other emergent motion of some regions.

The effects of glaciation were global. Antarctica was ice-bound throughout the Pleistocene and the preceding Pliocene. The Andes were covered in the south by the Patagonian ice cap. There were glaciers in New Zealand and Tasmania. The decaying glaciers of Mount Kenya, Mount Kilimanjaro, and the Ruwenzori Range in east and central Africa were larger. Glaciers existed in the mountains of Ethiopia and to the west in the Atlas Mountains. In the northern hemisphere, many glaciers fused into one. The Cordilleran Ice Sheet covered the North American northwest; the Laurentide covered the east. The Fenno-Scandian ice sheet covered northern Europe, including Great Britain; the Alpine ice sheet covered the Alps. Scattered domes stretched across Siberia and the Arctic shelf. The northern seas were frozen. During the late Upper Paleolithic (Latest Pleistocene) c. 18,000 BP, the Beringia land bridge between Asia and North America was blocked by ice,^[12] which may have prevented early Paleo-Indians such as the Clovis culture from directly crossing Beringia to reach the Americas.

According to Mark Lynas (through collected data), the Pleistocene's overall climate could be characterized as a continuous El Niño with trade winds in the south Pacific weakening or heading east, warm air rising near Peru, warm water spreading from the west Pacific and the Indian Ocean to the east Pacific, and other El Niño markers.^[14]

The Paleolithic is often held to finish at the end of the ice age (the end of the Pleistocene epoch), and Earth's climate became warmer. This may have caused or contributed to the extinction of the Pleistocene megafauna, although it is also possible that the late Pleistocene extinctions were (at least in part) caused by other factors such as disease and overhunting by humans.^[15][16] New research suggests that the extinction of the woolly mammoth may have been caused by the combined effect of climatic change and human hunting.^[16] Scientists suggest that climate change during the end of the Pleistocene caused the mammoths' habitat to shrink, resulting in a drop in population. The small populations were then hunted out by Paleolithic humans.^[16] The global warming that occurred during the end of the Pleistocene and the beginning of the Holocene may have made it easier for humans to reach mammoth habitats that were previously frozen and inaccessible.^[16] Small populations of woolly mammoths survived on isolated Arctic islands, Saint Paul Island and Wrangel Island, until c. 3700 BP and c. 1700 BP respectively. The Wrangel Island population became extinct around the same time the island was settled by prehistoric humans.^[17] There is no evidence of prehistoric human presence on Saint Paul island (though early human settlements dating as far back as 6500 BP were found on the nearby Aleutian Islands).^[18]

Nearly all of our knowledge of Paleolithic people and way of life comes from archaeology and ethnographic comparisons to modern hunter-gatherer cultures such as the !Kung San who live similarly to their Paleolithic predecessors.^[21] The economy of a typical Paleolithic society was a hunter-gatherer economy.^[22] Humans hunted wild animals for meat and gathered food, firewood, and materials for their tools, clothes, or shelters.^[22]

The population density was very low, around only 0.4 inhabitants per square kilometre (1/sq mi).^[2] This was most likely due to low body fat, infanticide, high levels of physical activity among women,^[23] late weaning of infants, and a nomadic lifestyle.^[2] In addition, even a large area of land could not support many people without being actively farmed – food was difficult to come by and so groups were prevented from growing too large by the amount of food they could gather. Like contemporary hunter-gatherers, Paleolithic humans enjoyed an abundance of leisure time unparalleled in both Neolithic farming societies and modern industrial societies.^[22][24] At the end of the Paleolithic, specifically the Middle or Upper Paleolithic, people began to produce works of art such as cave paintings, rock art and jewellery and began to engage in religious behavior such as burials and rituals.^[25]

At the beginning of the Paleolithic, hominins were found primarily in eastern Africa, east of the Great Rift Valley. Most known hominin fossils dating earlier than one million years before present are found in this area, particularly in Kenya, Tanzania, and Ethiopia.

By c. 2,000,000 – c. 1,500,000 BP, groups of hominins began leaving Africa, settling southern Europe and Asia. The South Caucasus was occupied by c. 1,700,000 BP, and northern China was reached by c. 1,660,000 BP. By the end of the Lower Paleolithic, members of the hominin family were living in what is now China, western Indonesia, and, in Europe, around the Mediterranean and as far north as England, France, southern Germany, and Bulgaria. Their further northward expansion may have been limited by the lack of control of fire: studies of cave settlements in Europe indicate no regular use of fire prior to c. 400,000 – c. 300,000 BP.^[26]

East Asian fossils from this period are typically placed in the genus Homo erectus. Very little fossil evidence is available at known Lower Paleolithic sites in Europe, but it is believed that hominins who inhabited these sites were likewise Homo erectus. There is no evidence of hominins in America, Australia, or almost anywhere in Oceania during this time period.

Fates of these early colonists, and their relationships to modern humans, are still subject to debate. According to current archaeological and genetic models, there were at least two notable expansion events subsequent to peopling of Eurasia c. 2,000,000 – c. 1,500,000 BP. Around 500,000 BP a group of early humans, frequently called Homo heidelbergensis, came to Europe from Africa and eventually evolved into Homo neanderthalensis (Neanderthals). In the Middle Paleolithic, Neanderthals were present in the region now occupied by Poland.

Both Homo erectus and Homo neanderthalensis became extinct by the start of the Upper Paleolithic. Descended from Homo sapiens, the anatomically modern Homo sapiens sapiens emerged in eastern Africa c. 300,000 BP, left Africa around 50,000 BP, and expanded throughout the planet. Multiple hominid groups coexisted for some time in certain locations. Homo neanderthalensis were still found in parts of Eurasia c. 40,000 BP years, and engaged in an unknown degree of interbreeding with Homo sapiens sapiens. DNA studies also suggest an unknown degree of interbreeding between Homo sapiens sapiens and Homo sapiens denisova.^[27]

Hominin fossils not belonging either to Homo neanderthalensis or to Homo sapiens species, found in the Altai Mountains and Indonesia, were radiocarbon dated to c. 30,000 – c. 40,000 BP and c. 17,000 BP respectively.

For the duration of the Paleolithic, human populations remained low, especially outside the equatorial region. The entire population of Europe between 16,000 and 11,000 BP likely averaged some 30,000 individuals, and between 40,000 and 16,000 BP, it was even lower at 4,000–6,000 individuals.^[28] However, remains of thousands of butchered animals and tools made by Palaeolithic humans were found in Lapa do Picareiro, a cave in Portugal, dating back between 41,000 and 38,000 years ago.^[29]

Some researchers have noted that science, limited in that age to some early ideas about astronomy (or cosmology),^{[citation needed]} had limited impact on Paleolithic technology. Making fire was widespread knowledge, and it was possible without an understanding of chemical processes. These types of practical skills are sometimes called crafts. Religion, superstitution or appeals to the supernatural may have played a part in the cultural explanations of phenomena like combustion.^[30]

Paleolithic humans made tools of stone, bone (primarily of deer), and wood.^[22] The early Paleolithic hominins, Australopithecus, were the first users of stone tools. Excavations in Gona, Ethiopia, have produced thousands of artifacts, and through radioisotopic dating and magnetostratigraphy the sites can be firmly dated to 2.6 million years ago. Evidence shows these early hominins intentionally selected raw stone with good flaking qualities and chose appropriately sized stones for their needs to produce sharp-edged tools for cutting.^[31]

The earliest Paleolithic stone tool industry, the Oldowan, began around 2.6 million years ago.^[32][33] It produced tools such as choppers, burins, and stitching awls. It was completely replaced around 250,000 years ago by the more complex Acheulean industry, which was first conceived by Homo ergaster around 1.8–1.65 million years ago.^[34] The Acheulean implements completely vanish from the archaeological record around 100,000 years ago and were replaced by more complex Middle Paleolithic tool kits such as the Mousterian and the Aterian industries.^[35]

Lower Paleolithic humans used a variety of stone tools, including hand axes and choppers. Although they appear to have used hand axes often, there is disagreement about their use. Interpretations range from cutting and chopping tools, to digging implements, to flaking cores, to the use in traps, and as a purely ritual significance, perhaps in courting behavior. William H. Calvin has suggested that some hand axes could have served as "killer frisbees" meant to be thrown at a herd of animals at a waterhole so as to stun one of them. There are no indications of hafting, and some artifacts are far too large for that. Thus, a thrown hand axe would not usually have penetrated deeply enough to cause very serious injuries. Nevertheless, it could have been an effective weapon for defense against predators. Choppers and scrapers were likely used for skinning and butchering scavenged animals and sharp-ended sticks were often obtained for digging up edible roots. Presumably, early humans used wooden spears as early as 5 million years ago to hunt small animals, much as their relatives, chimpanzees, have been observed to do in Senegal, Africa.^[36] Lower Paleolithic humans constructed shelters, such as the possible wood hut at Terra Amata.

Fire was used by the Lower Paleolithic hominins Homo erectus and Homo ergaster as early as 300,000 to 1.5 million years ago and possibly even earlier by the early Lower Paleolithic (Oldowan) hominin Homo habilis or by robust Australopithecines such as Paranthropus.^[2] However, the use of fire only became common in the societies of the following Middle Stone Age and Middle Paleolithic.^[1] Use of fire reduced mortality rates and provided protection against predators.^[37] Early h