Ancient History/Human Evolution/Human Origins
Examining Human Origins
The study of the deep past can be divided roughly into two sections: history, and prehistory. History assumes that the culture or people being studied had writing of some sort -- that they kept records of what they bought and sold, what they ate, what they saved, what they spent, and what they believed. Writing is one of the most important inventions of humans, and cultures that have writing are forever changed by it. Yet writing did not exist in some places until very recently, and even the oldest writing in the world is no more than 6500 years old.
By contrast, prehistory is the name we give to every part of human culture and experience that happened before the invention of writing. Most of the planet Earth had some form of writing by 1950 CE, which meant that in some places, prehistory lasted into the twentieth century. By contrast, prehistory extends back in time at least to 100,000 years ago. Prehistory may extend even farther than that, to one million years or even three million years! There is far more prehistory than history, and yet we know more about the last six thousand years than we do about the previous million.
Yet everything we know today about prehistory is as a result of the investigations of scientists. Many different scientists are working together in order to uncover the mysteries of prehistory. These scientists come in many types: paleoanthropologists, archaeologists, physical and cultural anthropologists, zoologists, chemists, botanists, physicists, historians and dedicated amateurs. It is difficult and under-appreciated work, but it is necessary if our understanding of the past is to advance.
Reconstructors of the Past
In order to understand prehistory, we first have to understand what these scientists are doing, and how they are doing it.
How do these different professions help us understand prehistory? How can we reconstruct the past without having any writing from that time period? In fact, each type of scientist mentioned has a specific role to play in understanding the past. Archaeologists and paleoanthropologists often have first-contact responsibilities when it comes to prehistory. Paleoanthropologists are scientists who look for and study old bones. When they find such bones, a paleoanthropologist can often learn many things about the animal it came from. Bones from an animal's limbs reveal whether an animal walked on two legs or four legs, whether it swam in the water or flew. A piece of a skull can reveal the size and shape of the animal's brain. Pieces of vertebrae can tell a scientist whether the animal walked upright or hunched over. Some bones even reveal what diseases an animal had. In the case of exploring human origins, old bones may reveal how long humanity has walked on the Earth, and what we have done in the world.
Paleoanthropologists combine the methods of paleontologists and biological anthropologists into one comprehensive study. Paleontology is the study of fossil evidence of ancient creatures, and biological anthropology is the inter-disciplinary study of physical changes in humans. Therefore, a paleoanthropologist is a scientist who studies fossil evidence of ancient human beings. Paleoanthropologists have played a major role in discovering what we know about evolution today.
Although fossils are a major piece of the puzzle, the theory of human evolution was built with the help of several other anthropological fields, all closely tied to paleoanthropology. For example, human behavioral ecology is the study of ancient human behavior and how it changed over time. Similar to archaeology, this field revealed how humans have adapted to changing environments and advanced technologically through the stone age. In addition, fields such as paleopathology, the study of ancient diseases, and osteology, the study of bones, have taken the findings of paleoanthropologists to new levels and provided more insight into the lives of ancient people.
Archaeologists do a slightly different task in the study of prehistory. Where paleoanthropologists study old human bones, archaeologists study ancient dwelling or burial places. Wherever people live, they often leave things behind when they move: pottery, an earring, food, tools, or garbage. Sometimes they leave the whole house behind. Where paleoanthropologists study bones, archaeologists study the remains of houses and shelters and camps where people lived. In addition, archaeologists sometimes study grave-sites, where people are buried, to examine the things the dead person's relatives left behind.
Archaeologists work through the study not only of objects, but their relationships to one another. When first excavating a site, an archaeologist will lay down a grid over the earth, usually constructed of stakes in the ground, and cords. The grid divides the land beneath it into many small squares of equal size. Once digging begins, a good archaeologist records what she or he finds, and where. The grid helps define what else a given object was found near. Thus, if a gold bracelet is found near the skeleton of a woman, the archaeologist may assume that the woman and the bracelet were buried at the same time. On the other hand, a bronze sword in the ground forty feet away and ten feet deeper probably was not buried at the same time as the woman or the bracelet.
Other professions perform supporting roles to archaeologists and paleoanthropologists. Chemists can do tests on the chemical composition of objects from ancient sites. Flint and obsidian, two types of stone used in prehistoric tools, have specific chemical signatures depending on where they come from, and obsidian from a volcano in eastern Turkey has a different signature than a volcano in Japan or in Spain or Italy. If an archaeologist in Morocco finds a hunter buried with a flint spear made with Iranian flint, she knows that either the hunter traveled a very long way before he died, or that the hunter had dealings with traders from far away. Chemists can also do Carbon Dating studies, in which organic material like bone, antler or wood is subjected to a chemical test. The test reveals the approximate age at which the organic thing died, and is usually accurate to within a century or two.
Zoologists, Botanists and Physicists
Zoologists and botanists help explore prehistory by studying the remains of animals and plants. Botanists can count seeds found at an archaeological site, and note the different kinds of seeds and nuts present. This reveals the landscape in which early humans lived. Perhaps the plants were suited to warmer or colder climates, or maybe they are extinct. Perhaps the plants had medicinal uses, or make food taste better. The archaeologist can sometimes tell if the seeds were being stored for eating or for planting, simply by knowing how many of a given kind are being stored. Zoologists can study animal bones to determine if the animal was domesticated or not. Knife marks on the bone reveal whether the animal was killed in order to be eaten. Small amounts of wool at a site can reveal whether or not a prehistoric culture sheared their animals to make thread and cloth.
Some physicists can do a similar test to radiocarbon dating called Potassium-Argon dating. This technology can get the date of an object wrong by more than a thousand years -- but it can also give the rough ages for objects that are hundreds of thousands of years older than radiocarbon can detect. Additionally, physicists have designed and built a number of technologies useful to archaeologists, including a side-scan ground-penetrating radar, that can find buildings and archaeological sites without digging them up.
Anthropologists are scientists who study human culture and behavior patterns. They contribute to the study of prehistory by examining the tools, clothing and equipment left behind at archaeological sites, and determine how that equipment was made and what it was used for. Physical anthropologists study human bones for signs of disease or malnutrition, and work with botanists and zoologists to reconstruct the diets of failed hunters. Cultural anthropologists study how ancient cultures made things, and what they thought and believed, based on the objects those cultures created and then abandoned.
Once all these scientists have done their jobs and learned what they can from the objects left behind by our most distant ancestors, they issue a report on their findings. A historian then takes the reports of many archaeologists, and tries to construct a coherent narrative or story of what was happening in the world or in a region of the world during the time period covered by these archaeological sites.
Amateurs and Volunteers
None of these jobs, from the historian to the paleoanthropologist, would be possible without the interest and excitement of dedicated and interested amateurs. Amateurs may not have much scientific training, but they can do the digging at archaeological sites, and sort bones and record information from a site on the grid. They can contribute to non-profit organizations that fund studies of prehistory, and they can read up on archeology and report the results to their friends. Amateurs can use their heads, hearts, eyes, ears and mouths to understand the past, just like anyone else, and they can transmit the excitement of studying the past to others.