The control of fire by early humans was a turning point in human cultural evolution that allowed for humans to proliferate due to the incorporation of cooked proteins and carbohydrates, expansion of human activity into the night hours, and protection from predators.[1]
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The earliest evidence of human usage of fire comes from various archaeological sites in East Africa, such as Chesowanja near Lake Baringo, Koobi Fora, and Olorgesailie in Kenya. The evidence at Chesowanja consists of red clay sherds dated to be 1.42 million years (Ma) Before Present (BP).[2] Reheating on the sherds found at the site show that the clay must have been heated to 400°C to harden.
At Koobi Fora, sites FxJjzoE and FxJj50 show evidence of control of fire by Homo erectus at 1.5 Ma BP, with the reddening of sediment that can only come from heating at 200—400°C.[2] A hearth-like depression exists at a site in Olorgesailie, Kenya. Some microscopic charcoal was found, but it could have resulted from a natural brush fire.[2]
In Gadeb, Ethiopia, fragments of welded tuff that appeared to have been burned were found in Locality 8E, but re-firing of the rocks may have occurred due to local volcanic activity.[2] These have been found amongst H. erectus created Acheulean artifacts.
In the Middle Awash River Valley, cone-shaped depressions of reddish clay were found that could be created by temperatures of 200°C. These features are thought to be burned tree stumps such that they would have fire away from their habitation site.[2] Burnt stones are also found in the Awash Valley, but volcanic welded tuff is also found in the area.
The earliest definitive evidence of human control of fire was found at Swartkrans, South Africa. Several burnt bones were found among Acheulean tools, bone tools, and bones with hominid-inflicted cut marks.[2] This site also shows some of the earliest evidence of carnivory in H. erectus. The Cave of Hearths in South Africa has burned deposits dated from 0.2 to 0.7 Ma BP, as do various other sites such as Montagu Cave (0.058 to 0.2 Ma BP) and at the Klasies River Mouth (0.12 to 0.13 Ma BP).[2]
The strongest evidence comes from Kalambo Falls in Zambia where several artifacts related to the use of fire by humans had been recovered including charred logs, charcoal, reddened areas, carbonized grass stems and plants, and wooden implements which may have been hardened by fire. The site was dated through radiocarbon dating to be at 61,000 BP and 110,000 BP through amino acid racemization.[2]
Fire was used to heat treat silcrete stones to increase their workability before they were knapped into tools by Stillbay culture.[3][4][5] This research identifies this not only with Stillbay sites that date back to 72,000 BP but sites that could be as old as 164,000 BP.[3]
A more recently discovered site at Bnot Ya'akov Bridge, Israel, shows H. erectus or H. ergaster fires made between 790 and 690 ka BP.[6] At Qesem Cave 12 km east of Tel-Aviv evidence exists of the regular use of fire from before 382,000 BP to around 200,000 BP at the end of Lower Pleistocene. The large quantities of burnt bone and moderately heated soil lumps suggest butchering and prey-defleshing took place near fireplaces.[7]
In Xihoudu in Shanxi Province, there is evidence of burning by the black, gray, and grayish-green discoloration of mammalian bones. Another site in China is Yuanmou in Yunnan Province, where blackened mammal bones have been found.[2]
At Trinil, Java, similar blackened bone and charcoal deposits have been found among H. erectus fossils.
At Zhoukoudian in China, evidence of fire is as old as 500,000 to 1.5 million BP.[8] Fire in Zhoukoudian is suggested by the presence of burned bones, burned chipped-stone artifacts, charcoal, ash, and hearths alongside H. erectus fossils in Layer 10 at Locality 1.[2][9] This evidence comes from Locality 1 at Zhoukoudian where several bones were found to be uniformly black to grey. The extracts from the bones were determined to be characteristic of burned bone rather than manganese staining. These residues also showed IR spectra for oxides, and a bone that was turquoise was reproduced in the laboratory by heating some of the other bones found in Layer 10. At the site, the same effect may have been due to natural heating, as the effect was produced on white, yellow, and black bones.[9] Layer 10 itself is described as ash with biologically produced silicon, aluminum, iron, and potassium, but wood ash remnants such as siliceous aggregates are missing. Among these are possible hearths "represented by finely laminated silt and clay interbedded with reddish-brown and yellow brown fragments of organic matter, locally mixed with limestone fragments and dark brown finely laminated silt, clay and organic matter."[9] The site itself does not show that fires were made in Zhoukoudian, but the association of blackened bones with stone artifacts at least shows that humans did control fire at the time of the habitation of the Zhoukoudian cave.
Multiple sites in Europe have also shown evidence of use of fire by H. erectus. The oldest has been found in Vértesszőlős, Hungary, where evidence of burned bones but no charcoal had been found. At Torralba and Ambrona, Spain, show charcoal and wood, Acheulean stone tools dated 0.3 to 0.5 Ma BP.[2]
At Saint-Estève-Janson in France, there is evidence of five hearths and reddened earth in the Escale Cave. These hearths have been dated to 200 ka BP.[2]
The mean evidence states that widespread control of fire began 125,000 BP.[8]
An important change in the behavior of humans was brought about by the control of fire and its accompanying light.[10] Activity was no longer restricted to the daylight hours. In addition, some mammals and biting insects avoid fire and smoke.[1][2] Fire also led to improved nutrition by cooked proteins.[1][9][11]
Richard Wrangham of Harvard University argues that cooking of plant foods may have triggered brain expansion by allowing complex carbohydrates in starchy foods to become more digestible and in effect allow humans to absorb more calories.[12][13][14]
Because of the indigestible components of plants such as raw cellulose and starch, certain parts of the plant such as stems, mature leaves, enlarged roots, and tubers would not have been part of the hominid diet prior to the advent of fire.[15] Instead, the diet consisted of the parts of the plants that were made of simpler sugars and carbohydrates such as seeds, flowers, and fleshy fruits. The incorporation of toxins into the seeds and similar carbohydrate sources also affected the diet, as cyanogenic glycosides such as those found in linseed, cassava, and manioc are made non-toxic through cooking.[15] The teeth of H. erectus and the wear on the teeth reflect the consumption of foods such as tough meats and crisp root vegetables.[16][17]
The cooking of meat, as evident from burned and blackened mammal bones, makes the meats easier to eat and easier to attain the nutrition from proteins by making the meat itself easier to digest.[18][19] The amount of energy needed to digest cooked meat is less than raw meat, and cooking gelatinizes collagen and other connective tissues as well, "opens up tightly woven carbohydrate molecules for easier absorption."[19] Cooking also kills parasites and food poisoning bacteria.
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. Anthropologists believe that H. erectus was the first human species to control fire.]] When humans first learned how to control fire this was an important step in their evolution. Humans could now eat cooked proteins and carbohydrates. They could also work longer into the night hours. Finally, fire gave a protection against predators.[1]
Contents |
The earliest evidence of humans using fire comes from many archaeological sites in East Africa, like Chesowanja near Lake Baringo, Koobi Fora, and Olorgesailie in Kenya. The evidence at Chesowanja consists of red clay shards dated to be 1.42 million years (Ma) Before Present (BP).[2] Reheating on the shards found at the site show that the clay must have been heated to 400°C to harden.
At Koobi Fora, sites show evidence of control of fire by Homo erectus at 1.5 Ma BP, with the reddening of sediment that can only come from heating at 200—400°C.[2] A hearth-like depression exists at a site in Olorgesailie, Kenya. Some very tiny charcoal was found, but it could have resulted from a natural brush fire.[2]
In Gadeb, Ethiopia, fragments of welded tuff that seemed to have been burned were found in Locality 8E, but re-firing of the rocks may have happened because of local volcanic activity.[2] These have been found among H. erectus created Acheulean artifacts.
In the Middle Awash River Valley, cone-shaped depressions of reddish clay were found that could be made by temperatures of 200°C. These features are thought to be burned tree stumps such that they would have fire away from their habitation site.[2] Burnt stones are also found in the "Awash Valley", but volcanic welded tuff is also found in the area.
The earliest definitive evidence of human control of fire was found at Swartkrans, South Africa. Many burnt bones were found among Acheulean tools, bone tools, and bones with hominid-inflicted cut marks.[2] This site also shows some of the earliest evidence of carnivory in H. erectus. The Cave of Hearths in South Africa has burned deposits dated from 0.2 to 0.7 Ma BP, as do many other places such as Montagu Cave (0.058 to 0.2 Ma BP) and at the Klasies River Mouth (0.12 to 0.13 Ma BP).[2]
The most powerful evidence comes from Kalambo Falls in Zambia where many things related to the use of fire by humans had been recovered like charred wood, charcoal, reddened areas, carbonized grass stems and plants, and wooden implements which may have been hardened by fire. The place was dated through radiocarbon dating to be at 61,000 BP and 110,000 BP through amino acid racemization.[2]
Fire was used to heat silcrete stones to increase their works before they were knapped into tools by Stillbay culture.[3][4][5] This clue shows this not only with Stillbay sites that date back to 72,000 BP but sites that could be as old as 164,000 BP.[3]
An important change in the behavior of humans occurred because of their control of fire and its accompanying light.[6] Activity was no longer restricted to the daylight hours. Some mammals and biting insects avoid fire and smoke.[1][2] Fire also led to better nutrition though cooked proteins.[1][7][8]
Richard Wrangham of Harvard University argues that cooking of plant foods may have triggered brain expansion, because it made complex carbohydrates in starchy foods easier to digest. This made humans absorb more calories.[9][10][11]
Stahl thought that because some parts of plants, like raw cellulose and starch are hard to digest in uncooked form, they would likely not be a part of the hominid diet before fire could be controlled.[12] These parts include stems, mature leaves, enlarged roots, and tubers. Instead, the diet consisted of the parts of the plants that were made of simpler sugars and carbohydrates such as seeds, flowers, and fleshy fruits. Another problem was that certain sees and carbohydrate sources are toxic. Cyanogenic glycosides, which can be found in linseed, cassava, and manioc, amongst others, are made non-toxic through cooking.[12] The teeth of H. erectus and the wear on the teeth reflect the consumption of foods such as tough meats and crisp root vegetables.[13][14]
The cooking of meat, as evident from burned and blackened mammal bones, makes the meats easier to eat. It is also easier to get the nutrition from proteins because the meat itself is easier to digest.[15][16] The amount of energy needed to digest cooked meat is less than that needed for raw meat, and cooking gelatinizes collagen and other connective tissues as well, it "opens up tightly woven carbohydrate molecules for easier absorption."[16] Cooking also kills parasites and food poisoning bacteria.
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