Archaeologists have also recorded how primitive forms of humans spread out of Africa into Asia about 1.8 million years ago, then into Europe about 900,000 years ago.The first physically modern humans, Homo sapiens sapiens, appeared in tropical Africa between 200,000 and 150,000 years agodates determined by molecular biologists and archaeologists working together.Archaeology became established as a formal discipline in the 19th and early 20th centuries.

radiocarbon dating can be used to directly date-31radiocarbon dating can be used to directly date-19

The earliest subjects of archaeological study date from the origins of humanity.

These include fossil remains believed to be of human ancestors who lived 3.5 million to 4.5 million years ago.

For the most part, the only things that survive are durable items such as potsherds (small fragments of pottery), tools or buildings of stone, bones, and teeth (which survive because they are covered with hard enamel).

Because many items disintegrate over time, archaeologists get an incomplete view of the past that they must fill in with other kinds of information and educated reasoning.

On rare occasions, however, delicate objects have been preserved.

For example, fabrics and flowers were found in the celebrated tomb of Tutankhamun, an Egyptian pharaoh who was buried in 1323 BC.Archaeologists have documented that the development of agriculture took place about 10,000 years ago.Early domesticationthe planting and harvesting of plants and the breeding and herding of animalsis evident in such places as the ancient settlement of Jericho in Jordan and in Tehuacn Valley in Mexico.With its focus on the ancient past, archaeology somewhat resembles paleontologythe study of fossils of long-extinct animals, such as dinosaurs.However, archaeology is distinct from paleontology and studies only past human life.The earliest archaeological sites include those at Hadar, Ethiopia; Olduvai Gorge and Laetoli, Tanzania; East Turkana, Kenya; and elsewhere in East Africa.