The earliest dispersal of the genus Homo: Homo erectus and

contemporariesOct. 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

• Bouri Skull from Ethiopia, ~1 Myr

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

Sangiran 17NG 6

Homo erectus from Indonesia

Perhaps surviving in Southeast Asia until as recently as 25-50 Ka?

Cultural remains at Zhoukoudian• Fire?

• Hunting? Or scavenging? probably both

• Many stone tools

• Cannibalism?

• Hunters or the Hunted?

Homo erectus from China

Other Chinese sites

• Lantian 650 Ka • Yunxian 350 Ka • Hexian 1.15 Ma

Summary of East African Homo erectus/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

Oldowan

Acheulian

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.