Archeologists and Paleoanthropologists rely on four kinds of evidence to learn about the past: Artifacts Ecofacts Fossils Features Together they provide a detailed story about human life long ago.

Anything made or modified by humans is an artifact. Most of the artifacts that archeologists look for and examine to reconstruct what was daily life like long ago are accumulated garbage of daily life – This is called archaeological records.

The most common artifacts from the past are stone tools, which archeologists call Lithics Humans first starting stone tools more than 2.5 million years ago. Used for almost every purpose.

Another common artifact is ceramic (pots and other items of baked clay). Humans started making ceramics about 10,000 years ago. Because they are both fragile and relatively easy to make, ceramics show up frequently in the garbage that makes up the archeological record.

Wood and bone artifacts are common as well. Used to make hide-working, cooking, hunting and even butchering tools. Unlike stone tools they tend not to survive well in the archeological record.

Ecofacts are natural objects that have been used or affected by humans. For example: bones from animals that people have eaten. These bones are somewhat like artifacts, but they haven’t been made or modified by humans.

Rare but particularly informative about human biological evolution. A fossil may be an impression of an insect or leaf on a muddy surface that is now a stone.

Sometimes it is consist of the actual hardened remains of an animal’s skeletal structure. When an animal dies, the organic matter that made up its body begins to deteriorate. The teeth and skeletal structure are composed largely of inorganic mineral salts, and soon they are all that remains.

We don’t have fossil remains of everything that lived in the past, and sometimes we only have fragments from one or few individuals. Robert Martin established that the earth has probably seen 6,000 primate species. Remains of only 3% of these species have been found.

Features are a kind of artifact, but archaeologist distinguished them from other artifacts because they cannot be easily removed from an archaeological site. Hearths are good example, when humans build a fire on bare ground the soil becomes heated and is changes. When archaeologists find a hearth, they find an area of hard, reddish soil often surrounded by charcoal and ash.

The most common features are called pits. Pits are simply holes dug by humans that are later filled with garbage or eroded soil. Living floors are another common type of features. These are the places where humans lived and worked.

A large or very deep area of such debris is called a midden. Midden are often the remains of garbage dumps or areas repeatedly used over long periods of time, such as caves. Buildings are a common feature on archaeological sites.

Evidence of the past is all around us, but finding them is not always easy. Archaeologists and paleoanthropologists usually restrict their search to what is called sites. Sites are know or suspected locations of human activities in the past that contain a record of that activity.

Sites are created when the remnants of human activity are covered or buried by some natural process. The most dramatic one is volcanic activity. The records of human behavior or humans themselves can be totally buried within seconds. The most impressive example of this must be Pompeii – an entire city that was buried in the eruption of Mount Vesuvius in A.D. 79. Today archaeologists are digging out the city and finding the remains of ancient life just as it was left in the moments before the eruption.

Less dramatic means of burring the record of human behavior are the natural processes of dirt accumulation and erosion. Wind and water-borne soil and debris can cover a site either quickly (as in a flood) or over a long period of time. The processes through which soils are built up can also bury artifacts in a way that allows archaeologists to uncover them later.

Since good locations to live and work in are often reused by humans, many sites contain the remains of numerous human occupations. Stratified: each layer, or stratum, of human occupation is separated like a layer in a cake.

Not only do stratified sites allow the archaeologist or paleoanthropologists to distinguish the sequence of site occupations, but the strata themselves provide a way to know the relative ages of the occupations – earlier occupations will always be below later ones.

The very processes that create sites can often damage or destroy them. Wind and water for example. Harold Dibble and his colleagues, for example, have argued that the Lower Paleolithic site of Cagny-L’Epinette in France does not actually contain locations where Lower Paleolithic people lived and worked. What looks like locations of human activities were created by water running across the site and accumulating artifacts in low-lying places. The study of the processes of site disturbance and destruction is called Taphonomy.

There is no single methods of finding sites, and indeed many sites are found by happenstance. Archaeologists and paleoanthropologists employ one of two basic methods: Pedestrian Survey: Walking around and looking for sites. Remote sensing: Much more high-tech way of finding sites.

A number of techniques are used to enhance the effectiveness of pedestrian survey. Use of sampling and systematic surveying methods to reduce the area to be covered by foot. By focusing their search on places humans are likely to have occupied.

Archaeologists find archaeological deposited by sensing their presence from a remote location, usually the current surface of the ground beneath which the archaeological deposits are buried. Most remove sensing techniques are borrowed from exploration geology, and are the same ones geologists use to find mineral or oil deposit.

Only one way to recover artifacts and fossils –excavation. Excavation is a complex process with two goals: 1.To find every scrap of evidence. 2.To record the horizontal and vertical location of that evidence with precision.

Few sites can even be fully excavated. The cost involved would be tremendous, and most archeologists feel it is important to leave some archeological deposits undisturbed for future archaeologists using new techniques. As a result archaeologists usually use some method of sampling.

Sampling however requires that archaeologists carefully plan where excavations will be conducted so that all areas of the site have an equal likelihood of being examined.

To date, no one has figured out a way to recover artifacts and fossils without destroying the site in the process. For this reason most excavation by professional archaeologists today is done only when a site is threatened with destruction.