ENVIRONMENTAL DYNAMICS OF EARLY PLEISTOCENE HUMAN EVOLUTION IN EAST ASIA

Research in the East African rift valley has drawn attention to strong environmental variability associated with Plio-Pleistocene hominin populations and its potential role in driving evolutionary change. Although habitat instability was influenced by global climate dynamics, environmental change caused by local tectonic events leads to the question whether the rift valley was atypical of the environmental and evolutionary settings of early hominin populations elsewhere. After East Africa, East Asia provides the next longest, continuous record of early human evolution, spanning approximately the past 1.7 million years. Recent research in the Nihewan Basin gives magnetostratigraphic and chronological context indicating the persistence of early human toolmakers in northeast Asia, coincident with several wide climatic shifts over a period of at least 400,000 years during the early Pleistocene (Zhu et al. 2001). Excavations in mid-Pleistocene deposits of the Bose Basin, southern China, have focused on red laterized sediments long considered to be indicative of a stable Pleistocene habitat. This research has uncovered large cutting tools, similar to Acheulean handaxes of Africa, made by populations that likely colonized a markedly disturbed landscape following tektite deposition and forest burning 803,000 years ago (Hou et al. 2000; Potts et al. 2000). Although the tempo of change differed from that of volcanically-disturbed environments of East Africa, East Asian temperate and subtropical zones also underwent strong climatic fluctuation and episodic, drastic environmental change to which early hominin populations were apparently able to successfully adapt. Detailed comparison of early human adaptability to East African and East Asian environmental dynamics will eventually help evaluate the evolutionary history of hominin populations in these two regions. References: Hou Y., et al., 2000, Science 287, 1622; Potts, R., et al., 2000, Science 289, 507a; Zhu R., et al., 2001, Nature 413, 413.