Q.We take for granted the use of heat and fire to destroy contaminants in our food. How did it come to pass that that early man decided to “cook” his food? What necessitated it?

A: No one knows when people first cooked food and controlled fire. Many experts believe fire was tamed in tropical Africa about 1.8 million years ago, but the date may actually be much later, perhaps nearer 600,000 years ago. We simply do not know.

Fire was probably tamed as a result of a lightning strike or some other accident. People then carried it in brands until they learned how to ignite it by rubbing soft and hard sticks together or by using a fire drill rubbed between the hands. Cooking food was obviously a byproduct of domestication, and it occurred quite naturally—perhaps when meat got burned in a fire and smelled good. Of course, this had the effect of destroying contaminants.

I don’t think anything necessitated cooking food. I think it simply happened as a logical extension of the domestication of fire, which was vital both for protection and as a hunting weapon.

Q: Why were the Maya so interested in astronomy?

A: The Maya used astronomy for two purposes. The first was to track the passage of the seasons of the agricultural year and the passing of the summer and winter solstices. Based on their observations of the Sun, the Maya constructed a calendar of 365 days.

The second way the Maya used astronomy was to track the ceremonial year, in which every day had intricate symbolic meaning. The Maya ceremonial year comprised 260 days. The Maya combined the agricultural year and the ceremonial year in a pair of interlocking calendars. Each day received two designations, one from the solar calendar and one from the ceremonial calendar.

The Maya image of the heavens was fundamental to their cosmology. They even used astronomy to dedicate buildings and to orient them toward planets and the cardinal directions.

Q: Who made the large stone megaliths on Easter Island and why?

A: The large stone statues on Easter Island are thought to be depictions of ancestral figures. Their style is Polynesian, and they were constructed for only a relatively short period of time, from about 800 to 1600. The task of carving and erecting many hundreds of these figures, some reaching 12 m (40 ft) in height, ultimately required more resources than the island could support. Large stone monuments called ahus are burial platforms, which were constructed to support rows of the figures.

Q: What is the earliest known use of money?

A: The first coinage appeared in Anatolia—the Asian part of modern-day Turkey—in about 600 bc. Money evolved from of the use of tokens as items of exchange by caravan merchants in southwestern Asia. It developed from a desire for standardized units of exchange of fixed value, and it soon spread widely through the Greek and Mediterranean worlds.

Q: Where did the Neandertals come from?

A: The classic squat and beetle-browed Neandertals of central and western Europe were the descendants of much earlier European settlers. These ancient settlers appear to have been Homo erectus, an archaic (premodern) human form that first evolved about 2 million years ago. Homo erectus migrated to Europe 600,000 or more years ago, and the Neandertals evolved from them over many millennia.

Q: How did Neandertals survive cold winters in ancient Europe?

A: Contrary to popular belief, Neandertals were not primitive brutes; they were exceptionally versatile hunters and gatherers. They had a relatively simple toolkit—composed of stone knives, scrapers, hand axes, cleavers, and other basic tools—but they appear to have made use of animal skins and fire to keep themselves warm.

With their stocky build and short limbs, Neandertals were well adapted to cold climates. In winter they took refuge in sheltered valleys and caves, but during the warmer months they ventured far and wide. Neandertals never settled in the bitterly cold areas of northern Europe and Eurasia close to the ice sheets of the late Ice Age. Such settlement didn’t occur until modern humans developed the needle and sewn, layered clothing for use in frigid environments.

Q: Why do some scientists believe Neandertals and modern humans interbred?

A: We know that in Europe Neandertals and modern humans coexisted for perhaps 10,000 years. In parts of Europe, archaeologists have uncovered artifacts and fossils of the same age belonging to each group. However, new genetic tests on Neandertal bones suggest that the two human forms were too incompatible to breed. By 30,000 years ago modern humans lived alone throughout Europe, and Neandertals had vanished, apparently driven into extinction by their more successful competitors.

Q: I’m interested in learning more about Dr. Meave Leakey’s recent find and the possibility of a new type of hominid. How does this find change what we currently believe?

A: Meave Leakey’s new hominid has been named Kenyapithecus platyops, “the flat-faced man of Kenya.” It was found near Lake Turkana in northern Kenya in the late 1990s and is thought to date from about 3.5 million years ago.

The find is very interesting because the fossil’s anatomical features are very different from Australopithecus afarensis, the well-known ancestral human found by Don Johanson in the 1970s. The new find has tiny teeth, a distinctive jaw structure, and a relatively modern face, all of which sets it apart from A. afarensis. This is why the Leakey team gave it the name of a new genus—to allow the intellectual elbowroom for scientists to deal with the increasing diversity of hominids in East Africa about 3 million years ago.

The Kenyan with a flat face is a fascinating but not unexpected discovery. It would have been naive of us to think that there were only a few hominid forms in East Africa at that critical time when the first humans were evolving. It only goes to show how diverse our early roots were—something which has been suspected for a long time and only now proven. But the relationship between K. platyops and A. afarensis will remain a mystery until more finds are made.

Q: How do archaeologists remove fossilized bone that is embedded in stone?

A: They carefully chip away at the stone with chisels, small hammers, dental picks, and brushes—a process that can take many months. Removing the stone without damaging the fossilized bone requires infinite patience.

Q: When did cultivation of plants begin in the Americas?

A: Agriculture in the Americas is very old. Cultivation of maize, which came from a native grass called teosinte, began in what is now south central Mexico at least 5,000 years ago, probably earlier. It may have been domesticated elsewhere as well at about the same time. Native Americans in eastern North America were experimenting with the cultivation of squash and indigenous grasses by 4000 bc, but maize did not arrive there until about ad 900. The potato was domesticated in the highland Andes of South America at least 4,000 years ago, probably considerably earlier. In what is now Peru, cultivated beans, including the lima bean, made their appearance by 7000 bc.

Q: Are there any peoples of the world who remain unaffected by modern influences?

A: There were half a century ago, but there probably aren’t today. It is possible, though increasingly unlikely, that small populations of isolated peoples still survive in remote parts of New Guinea or the Amazon Basin.

Q: What is the importance of the Rosetta Stone?

A: The Rosetta Stone, which bears an inscription in three languages, provided the key to deciphering ancient Egyptian hieroglyphics. The inscription is a proclamation by pharaoh Ptolemy V on the occasion of his coronation at Memphis, the ancient capital of Egypt, on March 27, 196 bc, decreeing measures aimed at securing the support of the indigenous population. The decree leaves those who read or heard it in no doubt of the divinity of the pharaoh: “Since King Ptolemy, the ever-living, beloved of Ptah, the god Manifest and Beneficent, born of King Ptolemy and Queen Arsinoe, Father-loving gods, has conferred many benefits on the temples and those who dwell in them and on all the subjects in his kingdom, being a god born of a god and goddess…” The Rosetta Stone was found in 1799 by a French officer, who was helping to build a fortification in the town of that name in the Egyptian Delta. French scholar Jean François Champollion deciphered the stone in 1822.