The earliest dispersal of the genus Homo: Homo erectus and contemporaries Oct. 14, 2008
Introduction • The Pleistocene • Early (or Lower) 1.8 - 0.78 Mya • Middle - 0.78 - 0.125 • Late (or Upper) - 0.125 - 0.01 • ~ 2 Mya hominins disperse outside Africa • Widely distributed in space and time • Morphological variation in geographical groups • All hominins outside Africa belong to the genus Homo
Many generic names prior to Modern Evolutionary Synthesis Africanthropus, Anthropus, Archanthropus, Atlanthroprus, Cyphanthropus, Euranthropus, Hemianthropus, Palaeanthropus, Palaeoanthropus, Pithecanthropus, Praehomo, Protanthropus, Pseudohomo, Maueranthropus, Meganthropus, Nipponanthropus, Notoanthropus & Sinanthropus = Homo
A new kind of hominid • Discoveries of Homo erectus began in the late 19th century, e.g. E. Dubois in Java (Pithecanthropus); then later in the early 20th century in China (Sinanthropus). • Homo erectus in East Africa by 1.8 Mya • Homo erectus (Asia) or Homo ergaster (Africa) • Grade - A grouping of organisms sharing a similar adaptive pattern. It is not necessarily based on closeness of evolutionary relationship, but does contrast organisms in a useful way. • Clade - A monophyletic grouping of organisms that all share a common ancestor. • Adaptive shift (including diet, body size and habitat) has taken place.
Morphology of Homo erectus • Brain size – Range750 to 1,250 cc (900 average) • Body size – limb proportions like that of modern humans but skeletal-muscular features are more robust • Cranial shape – thick cranial bones, large browridge, projecting nuchal torus, sagittal keeling, broad cranial base • Dentition – similar to modern humans but posterior teeth larger
East Africa • Olduvai, Tanzania – OH 9, 1.4 Mya • East Turkana, Kenya – KNM-ER 3733, 1.8 Mya • West Turkana, Kenya – KNM-WT 15000, 1.6 Mya • Bouri, Ethiopia – Cranium displays features of Homo erectus fossils from Africa and East Asia, 1 Mya
Nariokotome or Turkana Boy • KNM-WT 15000
Who were the Earliest African Emigrants? • Dmanisi, Georgia – ~ 1.75 Mya • Why disperse from Africa? • Traveling with food source? • Increase in population size led to the need for more space and resources?
Dmanisi Hominins • Oldest and best preserved hominin fossils found outside Africa; 1.75 Mya. • Low braincase, wide base, brain size 650-780 cc, thickening along sagittal midline • Less robust, short stature thinner browridge, projecting lower face, large upper canine • Many stone tools, Oldowan or Mode 1
Historical overview of Homo erectus discoveries • Distributed across Africa and Eurasia • ~ 1.8 Mya to as late as 50,000-25,000 in Pacific Southeast Asia • Java – along the Solo river near Trinil Dutch anatomist Dubois found a skullcap and later a femur in 1891. Other important sites - Sangiran and Ngandong • Peking (Beijing) – at Zhoukoudian (Middle Pleistocene, ~400 Ka) many fossil specimens (cranial and postcranial) and stone tools studied by Black and Weidenreich in the 1920s and 1930s
Homo erectus from Indonesia Sangiran 17 NG 6 Perhaps surviving in Southeast Asia until as recently as 25-50 Ka?
Homo erectus from China Cultural remains at Zhoukoudian • Fire? • Hunting? Or scavenging? probably both • Many stone tools • Cannibalism? • Hunters or the Hunted?
Other Chinese sites • Lantian 650 Ka • Yunxian 350 Ka • Hexian 1.15 Ma
Summary of East African Homoerectus/ergaster • African Homo erectus fossils aren’t as robust as East Asian Homo erectus • One or more species? • Considerable variation in size and morphological features, both cranial and postcranial
North Africa and Europe • Algeria 700 Ka and Morocco 500 Ka • Ceprano, Italy 800-900 Ka
Technological and population trends in Homo erectus • Technological trends – 1.4 Mya Acheulian or Mode 2 replaces the Oldowan or Mode 1 • Population trends – increase in group and population size coupled with wider geographical distribution
Interpretations of Homo erectus: Continuing uncertainties • One or more species? • Grade or Clade? • What preceded early Homo? • Ancestor of modern humans? • Cognitive developments? • Why emigrate from Africa? • How many dispersals and how many species?
Stw53 KNM-ER 1813
Hunting or scavenging? Probably both.