Control of fire by early humans

A reconstruction of Homo erectus, the earliest human species that is known to have controlled fire

The control of fire by early humans was a turning point in the cultural aspect of human evolution that allowed humans to cook food and obtain warmth and protection. Making fire also allowed the expansion of human activity into the colder hours of the night, and provided protection from predators and insects.^[1]

Incontrovertible evidence of widespread control of fire dates to approximately 125,000 years ago and later.^[2] Evidence for the controlled use of fire by Homo erectus beginning some 400,000 years ago has wide scholarly support, while claims regarding earlier evidence are mostly dismissed as inconclusive or sketchy.^[3]

Claims for the earliest definitive evidence of control of fire by a member of Homo range from 0.2 to 1.7 million years ago (Mya).^[4]

Lower Paleolithic evidence

All evidence of control of fire during the Lower Paleolithic is uncertain and has at best limited scholarly support. In fact, definitive evidence of controlled use of fire is one of the factors characteristic of the transition from the Lower to the Middle Paleolithic in the period of 400,000 to 200,000 BP.

East African sites, such as Chesowanja near Lake Baringo, Koobi Fora, and Olorgesailie in Kenya, show some possible evidence that fire was utilized by early humans. At Chesowanja, archaeologists found red clay sherds dated to be 1.42 Mya.^[4] Reheating on these sherds show that the clay must have been heated to 400 °C (752 °F) to harden. At Koobi Fora, sites FxJjzoE and FxJj50 show evidence of control of fire by Homo erectus at 1.5 Mya, with the reddening of sediment that can only come from heating at 200–400 °C (392–752 °F).^[4] 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.^[4] 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.^[4] 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 have been created by temperatures of 200 °C (392 °F). These features are thought to be burned tree stumps such that they would have fire away from their habitation site.^[4] Burnt stones are also found in the Awash Valley, but volcanic welded tuff is also found in the area.

A site at Bnot Ya'akov Bridge, Israel, has been claimed to show that H. erectus or H. ergaster made fires between 790,000 and 690,000 BP.^[5]

In Xihoudu in Shanxi Province, China, there is evidence of burning by the black, gray, and grayish-green discoloration of mammalian bones found at the site. Another site in China is Yuanmou in Yunnan Province, where blackened mammal bones were found in 1985 and dated to 1.7 Ma BP.^[4]

At Trinil, Java, similar blackened bone and charcoal deposits have been found among H. erectus fossils, dated from 500,000 to 830,000 BP.^[4]

Middle Paleolithic evidence

Africa

The earliest definitive evidence of human control of fire was found at Swartkrans, South Africa.^[6] Several burnt bones were found among Acheulean tools, bone tools, and bones with hominid-inflicted cut marks.^[4] 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 200,000 to 700,000 BP, as do various other sites such as Montagu Cave (58,000 to 200,000 BP) and at the Klasies River Mouth (120,000 to 130,000 BP).^[4]

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.^[4]

Fire was used to heat treat silcrete stones to increase their workability before they were knapped into tools by Stillbay culture.^[7][8][9] 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.^[7]

Asia

Zhoukoudian Caves, a World Heritage Site and an early site of human use of fire in China

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.^[10]

At Zhoukoudian in China, evidence of fire is as early as 230,000 to 460,000 BP.^[2] 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.^[4][11] 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.^[11] 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."^[11] 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.

Europe

Multiple sites in Europe have also shown evidence of use of fire by later versions of H. erectus. The oldest has been found in England at the site of Beeches Pit; Uranium series dating and TL dating place the use of fire at 415,000 BP.^[12] At Vértesszőlős, Hungary, where evidence of burned bones, but no charcoal, had been found, dating from c. 350,000 years ago. At Torralba and Ambrona, Spain, show charcoal and wood, Acheulean stone tools dated 300,000 to 500,000 BP.^[4]

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 200,000 BP.^[4]

Changes to behavior

An important change in the behavior of humans was brought about by the control of fire and its accompanying light.^[13] Activity was no longer restricted to the daylight hours. In addition, some mammals and biting insects avoid fire and smoke.^[1][4] Fire also led to improved nutrition by cooked proteins.^[1][11][14]

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.^[15][16][17] Wrangham has also suggested that eating cooked food is more "natural" for the human digestive system, because he thinks that the human digestive system may have evolved to deal with cooked foods, and that cooking explains the increase in hominid brain sizes, smaller digestive tract, smaller teeth and jaws and decrease in sexual dimorphism that occurred roughly 1.8 million years ago. He also argues that raw meat and vegetables could not have provided the necessary calories to support the normal hunter–gatherer lifestyle.^[18][19]

Other anthropologists oppose Wrangham,^[20] stating that archeological evidence suggests that cooking fires began in earnest only 250,000 BP, when ancient hearths, earth ovens, burnt animal bones, and flint appear across Europe and the Middle East. Two million years ago, the only sign of fire is burnt earth with human remains, which most other anthropologists consider to be mere coincidence rather than evidence of intentional fire.^[21] The mainstream view among anthropologists is that the increases in human brain-size occurred well before the advent of cooking, due to a shift away from the consumption of nuts and berries to the consumption of meat.^[22][23]

Changes to diet

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.^[24] Instead, the consumption of plants would be limited to parts 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.^[24]

The teeth of H. erectus over time showed gradual shrinking, suggesting that later members of the species transitioned from eating crunchier foods such as crisp root vegetables to softer foods such as meat and various cooked foods.^[25][26] The evidence of cooking of meat comes from burned and blackened animal bones found at various archaeological sites.^[27]

Wrangham suggested that by cooking meat, it acted as a form of "pre-digestion", allowing less caloric intake to be spent on digesting the tougher proteins such as collagen and the tougher carboyhydrates. The digestive tract shrunk, allowing more calories to be given to the growing brain of H. erectus.^[28] Other scientists disagree with Wrangham's assumption. Neurobiologist John Allman believes that cooking did not affect the brain development of H. erectus, but rather contributed to the development of the brain in Neanderthals and early modern humans. Paleoanthropologist C. Loring Brace agrees with Allman's theory that cooking did not affect H. erectus development, stating that he has only found evidence of earth-oven cookware from the past 200,000 years, which does not correlate with the earliest known use of fire from 800,000 years ago. Carel van Schaik believes that cooking did contribute to human evolution, but it was not the only factor that lead to the increased brain power of modern hominids. Rather, as Leslie Aiello suggests, the changes came in groups; increased consumption of meat, the smaller digestive system, cooking, and upright walking all contributed to the growth of the brain.^[28]

Dental anthropologist Peter Lucas suggests that the advent of cooking and preparing it by making food easier to chew led to the issues of malocclusion in modern humans and a steady decrease in the size of teeth. Because the food was made smaller, but not less tough, the human jaw shrank too much to adequately fit all of the teeth.^[29]

See also

Fire portal

• Hunting hypothesis
• Savanna theory

References

1. ^ ^{a b c} Price, David. "Energy and Human Evolution". http://www.dieoff.org/page137.htm. Retrieved 2007-11-12. 
2. ^ ^{a b} "First Control of Fire by Human Beings--How Early?". http://www.beyondveg.com/nicholson-w/hb/hb-interview2c.shtml. Retrieved 2007-11-12. 
3. ^ Price, David. "Energy and Human Evolution". http://www.dieoff.org/page137.htm. Retrieved 2007-11-12. "Fire was used by Homo erectus in northern China more than 400,000 years ago, and there is sketchy evidence suggesting that it may have been used long before that (Gowlett, 1984, pp. 181-82)" 
4. ^ ^{a b c d e f g h i j k l m n o} James, Steven R. (February 1989). "Hominid Use of Fire in the Lower and Middle Pleistocene: A Review of the Evidence". Current Anthropology (University of Chicago Press) 30 (1): 1–26. doi:10.1086/203705. 
5. ^ Rincon, Paul (April 29, 2004). "Early human fire skills revealed". BBC News. http://news.bbc.co.uk/2/hi/science/nature/3670017.stm. Retrieved 2007-11-12. 
6. ^ Renfrew and Bahn (2004). Archaeology: Theories, Methods and Practice (Fourth Edition). Thames and Hudson. Page 341.
7. ^ ^{a b} Brown KS, Marean CW, Herries AI, Jacobs Z, Tribolo C, Braun D, Roberts DL, Meyer MC, Bernatchez J. (2009). Fire As an Engineering Tool of Early Modern Humans. Science, 325: 859-862. doi:10.1126/science.1175028
8. ^ Webb J. Domanski M. (2009). Fire and Stone. Science, 325: 820-821. doi:10.1126/science.1178014
9. ^ Callaway. E. (13 August 2009) Earliest fired knives improved stone age tool kit New Scientist, online
10. ^ Karkanas P, Shahack-Gross R, Ayalon A, et al. (August 2007). "Evidence for habitual use of fire at the end of the Lower Paleolithic: site-formation processes at Qesem Cave, Israel". J. Hum. Evol. 53 (2): 197–212. doi:10.1016/j.jhevol.2007.04.002. PMID 17572475. http://www.tau.ac.il/humanities/archaeology/info/ran_barkai/HabitualUseofFireJHE2007.pdf. 
11. ^ ^{a b c d} Weiner, S.; Q. Xu, P. Goldberg, J. Liu, O. Bar-Yosef (1998). "Evidence for the Use of Fire at Zhoukoudian, China". Science 281 (5374): 251–253. doi:10.1126/science.281.5374.251. PMID 9657718. 
12. ^ Preece, R. C. (2006). "Humans in the Hoxnian: habitat, context and fire use at Beeches Pit, West Stow, Suffolk, UK". Journal of Quaternary Science (Wiley): 485–496. 
13. ^ Stone, Linda; Paul F. Lurquin, Luigi Luca Cavalli-Sforza (2007). Genes, Culture, And Human Evolution: A Synthesis. Blackwell Publishing. p. 33. 
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17. ^ Lambert, Craig (May–June 2004). "The Way We Eat Now". Harvard Magazine. http://harvardmagazine.com/2004/05/the-way-we-eat-now.html. 
18. ^ Clement, Brian (2006). "The Cooking Enigma". In Ungar, Peter S.. Evolution of the Human Diet: The Known, the Unknown, and the Unknowable. Oxford, USA: Oxford University Press. pp. 308–23. ISBN 0195183460. 
19. ^ Wrangham, R; Conklin-Brittain, N (2003). "'Cooking as a biological trait'.". Comparative biochemistry and physiology. Part A, Molecular & integrative physiology 136 (1): 35–46. doi:10.1016/S1095-6433(03)00020-5. PMID 14527628. http://artsci.wustl.edu/~hpontzer/Courses/Wrangham&Conklin-Britain2003CBP%20Cooking%20as%20a%20Biological%20Trait.pdf. 
20. ^ Pennisi, Elizabeth (March 26, 1999). "Human evolution: Did Cooked Tubers Spur the Evolution of Big Brains?". Science 283 (5410): 2004–2005. doi:10.1126/science.283.5410.2004. PMID 10206901. http://cogweb.ucla.edu/Abstracts/Pennisi_99.html. 
21. ^ Gorman, RM (2008). "Cooking up bigger brains.". Scientific American 298 (1): 102, 104–5. doi:10.1038/scientificamerican0108-102. http://www.sciam.com/article.cfm?id=cooking-up-bigger-brains. 
22. ^ "Meat-eating was essential for human evolution, says UC Berkeley anthropologist specializing in diet". June 14, 1999. http://berkeley.edu/news/media/releases/99legacy/6-14-1999a.html. Retrieved 2010-12-06. 
23. ^ Mann, Neil (August 15, 2007). "Meat in the human diet: An anthropological perspective". Nutrition & Dietetics 64 (Supplement s4): 102–107. doi:10.1111/j.1747-0080.2007.00194.x. 
24. ^ ^{a b} Stahl, Ann Brower (April 1984). "Hominid Dietary Selection Before Fire". Current Anthropology (University of Chicago Press) 25 (2): 151–168. doi:10.1086/203106. 
25. ^ Viegas, Jennifer (November 22, 2005). "Homo erectus ate crunchy food". News in Science (abc.net.au). http://www.abc.net.au/science/articles/2005/11/22/1514032.htm. Retrieved 2007-11-12. 
26. ^ "Early Human Evolution: Homo ergaster and erectus". http://anthro.palomar.edu/homo/homo_2.htm. Retrieved 2007-11-12. 
27. ^ "What evidence is there that Homo erectus used fire? Why did they use it?". http://www.digonsite.com/drdig/earlyman/33.html. Retrieved 2007-11-12. 
28. ^ ^{a b} Gibbons, Ann (June 15, 2007). "Food for Thought" (pdf). Science 316 (5831): 1558. doi:10.1126/science.316.5831.1558. PMID 17569838. http://www.sciencemag.org/cgi/reprint/316/5831/1558.pdf. Retrieved 2007-11-12. 
29. ^ Pickrell, John (2005-02-19). "Human 'dental chaos' linked to evolution of cooking". http://www.newscientist.com/article/dn7035-human-dental-chaos-linked-to-evolution-of-cooking.html. Retrieved 2011-10-07. 

Further reading

• Goudsblom, J (1992): Fire and Civilization, Allen Lane.