Today, archaeologists and other scientists have ways of preserving such fragile artifacts.
Archaeologists now make detailed maps that identify the location of every artifact they find at an archaeological site. By analyzing this evidence, they can usually tell what activities took place at different locations within the site. Chips of flint stone might suggest the workplace of a toolmaker. Piles of shells or gnawed bones may show a prehistoric garbage pit.
Archaeologists work with experts in many fields of science. Archaeologists studying very ancient sites need to find out how old an artifact is. For help determining the age of objects, they turn to geologists, or experts on earth science. Geologists can date the age of rocks found in and around an archaeological site.
Other scientists, such as botanists and zoologists—experts on plants and on animals—examine seeds and animal bones to learn about the diets of our ancestors. Experts on climate can help archaeologists determine what conditions our ancestors faced on the plains of Africa or in ice-covered parts of Europe.
Biologists analyze fragments of human bone to determine the person's gender or age. In recent decades, advances in genetics, or the study of heredity and inherited characteristics, have provided new evidence about early people, such as their migration, or movement, across the world.
“Lucy” was discovered in Ethiopia in 1974. Scientists date the skeleton to at least 3 million years ago. It was the first time archaeologists had enough of one skeleton to reconstruct and view an actual hominid.
Today, archaeologists use many modern technologies to study and interpret their findings. Computers are used to store and sort data or to develop accurate site maps. Aerial photography can reveal patterns of how people used the land. Chemists and physicists have developed techniques that measure radioactivity, which allows them to determine the age of objects.
Why is it that the farther down an archaeologist digs, the more he or she can find out about the past?
Since the 1870s, scholars have worked to learn about the ancestors of modern humans. They have examined fossils, or remains of ancient life preserved in ancient rock. Fossils might include footprints, impressions of leaves, bones, or even skeletons.
Prehistoric groups did not have cities, countries, organized central governments, or complex inventions, so clues about them were hard to find. Before the 1950s, anthropologists knew little about early humans and their ancestors. However, archaeologists in East Africa started uncovering ancient footprints, bones, and tools. With these first key discoveries, scholars began to form a picture of life during prehistory.
In the 1930s, anthropologists Mary Leakey and Louis Leakey started searching for clues to the human past in a deep canyon in Tanzania called Olduvai Gorge(OHL duh vy). Geologists have dated the bottom layers of Olduvai Gorge to an age of 1.7 to 2.1 million years.
As the Leakeys searched the sides of the gorge, they found very ancient tools chipped from stone. Although these tools looked simple, with jagged edges and rough surfaces, they showed that whoever had made them had learned to develop technologies to help them survive.
Technology refers to the skills and tools people use to meet their basic needs and wants. More recent stone tools proved more sophisticated—both smooth and polished—but the older ones were exciting to the Leakeys. They felt there must be evidence of the makers of those tools in Olduvai Gorge as well.
In 1959, after more than two decades of searching, Mary Leakey found pieces of bone embedded in ancient rock at Olduvai Gorge.