A lot of important things happened at the start of the Pleistocene, just after 2 m.y.a. Homohabilis gave rise to Homoerectus, a definite member of the genus Homo, exhibiting a larger brain, thicker enamel, and a reduction in sexual dimorphism. Homo erectus was essentially human below the neck. The rise of erectus also saw a doubling in brain size, a dramatic geographic expansion of the genus, and major changes in technology. For the first time, human fossil material was found outside of Africa, documenting the expansion of population and occupation of new habitats. The handaxe was invented and became the hallmark of the Lower Paleolithic.

This chapter covers some of the major finds from this period including early work on the island of Java by the Dutch surgeon Dubois and the finds of Pithecanthropus and the discoveries of Homo erectus at Zhoukoudian in China. Also discussed are the new finds from Atapuerca, one of the most exciting early human fossil sites — and the earliest in Europe. The chapter returns to Africa using Kalambo Falls and Olorgesailie as examples of the Acheulean in this region and the remarkable finds of plant remains at Kalambo.

The chapter also discusses the Pleistocene and the Paleolithic as hallmarks of this important time in human evolution. The Pleistocene is covered as a cold crucible in which much of our evolution took place. Pleistocene mammals are the subject of a block in the chapter to document both the richness of the fauna and the substantial changes in the environment that were taking place. This chapter introduces archaeological chronology with the Stone Age and Paleolithic and spends some time with the hand ax as the hallmark of the Lower Paleolithic.