Million Year Old Fire Pit

This is hard evidence that the use of fire came early and was the enabling tool more than any other that then drove the domestication of humanity.  This domestication led to the changeover of our face and jaws and plausibly the increase in our brain size.

As important, fire opened up a wide range of new plant foods that became abundant in the diet.  It likely drove the transition to a more plant based diet as enough then could be consumed without a bulky body.  Recall that a bear in the spring eats a marine sedge which only releases twenty percent food value.  Most wild plants are just as parsimonious when eaten raw.

With fire, the stew pot soon took over.  Toxic roots became viable starch and tough gamy meat broke down enough to eat easily.  We eat that way today.

Usually unspoken though is that fire immediately enhanced tool making itself with the invention of the fire hardened spear which has been in use continuously ever since to this day.  This was a vast improvement over the previous throwing stone.  Unfortunately, it fails to leave a trace in the archeological record.

Hot Find! Humans Used Fire 1 Million Years Ago

Charles Choi, LiveScience Contributor

Date: 02 April 2012 Time: 03:01 PM ET

Researchers found evidence of human fire use in South Africa's Wonderwerk Cave (shown here), a massive cavern located near the edge of the Kalahari Desert.
CREDIT: M. Chazan 

http://www.livescience.com/19425-earliest-human-fire.html

Ash and charred bone, the earliest known evidence of controlled use of fire, reveal that human ancestors may have used fire a million years ago, a discovery that researchers say will shed light on this major turning point in human evolution.

Scientists analyzed material from Wonderwerk Cave in South Africa, a massive cavern located near the edge of the Kalahari Desert. Previous excavations there had uncovered an extensive record of human occupation.

Microscopic analysis revealed clear evidence of burning, such as plant ash and charred bone fragments. These materials were apparently burned in the cave, as opposed to being carried in there by wind or water, and were found alongside stone tools in a layer dating back about 1 million years. Surface fracturing of ironstone, the kind expected from fires, was also seen.

Micrograph of burned bone on a paleosurface at Wonderwerk Cave in South Africa.
CREDIT: Image courtesy of P. Goldberg.

Although modern humans are the only human species alive today, originating about 200,000 years ago, other human species once roamed the Earth, such as Homo erectus, which arose about 1.9 million years ago.

"The analysis pushes the timing for the human use of fire back by 300,000 years, suggesting that human ancestors as early as Homo erectus may have begun using fire as part of their way of life," said researcher Michael Chazan, a paleolithic archaeologist at the University of Toronto and director of the university's archaeology center.

The research team's analysis suggests that materials in the cave were not heated above about 1,300 degrees Fahrenheit (700 degrees Celsius). This is consistent with preliminary findings that grasses, brushes and leaves were burned for these fires — such fuel would not have been capable of hotter flames.

Fire would have helped early humans stay warm and keep nighttime predators at bay, and enabled cooking, which would have made food more digestible. In addition, "socializing around a campfire might actually be an essential aspect of what makes us human," Chazan said. "The control of fire would have been a major turning point in human evolution."

Harvard anthropologist Richard Wrangham has speculated that controlled fires and cooked meat even influenced human brain evolution. He suggests that humans were cooking their prey as far back as the first appearance of Homo erectus 1.9 million years ago, just when humans were experiencing major brain expansion, and proposes that cooking allowed our ancestors to evolve larger, more calorie-hungry brains and bodies, and smaller guts suited for more easily digested cooked food.

"It's possible we may find evidence of fire use as early as Wrangham has suggested," Chazan told LiveScience.

Future research will analyze both earlier and later materials from this site to see how fire use might have developed over time.

"We're opening the question of how fire fit into the life of early humans and how that might have changed over time," Chazan said.

The scientists detailed their findings online April 2 in the journal Proceedings of the National Academy of Sciences.