Brain Size

1. Brain Size Homo Sapien Skulls  1. Australopithecus afarensis 2. Australopithecus africanus 3. Homo habilis 4. Homo erectus 5. Homo Neandertalensis Cranial capacities 700 cm3 to 1250 cm3 Brain size closely linked with overall body size H. erectus is larger-bodied than early Homo sample but relative brain size is about the same Relative brain size of H. erectus is considerably less encephalized than later members of genus Homo

2. Cranial Shape Thick cranial bone, large browridges (supraorbital tori), and projecting nuchal torus Braincase long and low, with little forehead development Cranium wider at base, compared with earlier and later species Sagittal keel, a small ridge from front to back along the sagittal suture, reflects bone buttressing in a very robust skull, rather than a specific function

3. Homo Erectus findsAfrica, Asia, Indonesia, Europe

4. Homo erectus from Africa • Homo erectus evolved first in Africa, supported by evidence of: • Earlier hominins prior to the appearance of H. erectus occurring in Africa. • 1.8 mya fossils at East Turkana, in Kenya, and not long after at other sites in East Africa. • Though, 1.75 mya populations in southeastern Europe; 1.6 mya populations in Indonesia, suggesting quick migrations

5. TURKANA BOYa.k.a. Nariokotome Skeleton WT 15000 In 1984, Kamoya Kimeu discovered a small piece of skull on the west side of Lake Turkana at the site known as Nariokotome. The excavations produced the most complete H. erectus skeleton ever found Facial bones, a pelvis, and most of the limb bones, ribs, and vertebrae.

6. TURKANA BOYNariokotome Skeleton • The Nariokotome skeleton is dated to about 1.6 mya. • The skeleton is that of a boy about 12 years of age with an estimated height of 5 feet 3 inches.

7. Olduvai Gorge • Find by Louis Leakey in 1960, includes well-preserved cranial vault with small part of upper face. • Dated at 1.4 mya, the cranial capacity is the largest of all the African H. erectus specimens. • The browridge is the largest known for any hominin, but the walls of the braincase are thin. • Similar to East African H. erectus specimens; differs from thickcranial bones in Asian H. erectus.

8. Gona Evidence Ethiopia find dated to appx. 1.3 mya Female pelvis with very wide birth canal, indicating large-brained infants in utero Perhaps newborn H. erectus with a brain that was comparable to typical modern human baby Suggests, when compared with Nariokotome pelvis, considerable sexual dimorphism in skeletal anatomy is linked to reproduction and body size

9. Daka Evidence Middle Awash of Ethiopia find dated to appx. 1 mya Complete cranium more like Asian H. erectus than most earlier East African remains discussed Discounts argument that East African fossils are different species than Asian H. erectus

11. The Earliest African Emigrants Why they left is a mystery A greater range of physical variation in specimens outside of Africa at about 1.8 mya Into Java, Indonesia by 1.6 mya Equates to less than 200,000 years to travel from East Africa to Southeast Asia

12. The Dmanisi Hominins The discovery of the Dmanisi materials in the Republic of Georgia began in the early 1990s. The most informative specimens are four well-preserved crania, with one recently discovered being almost complete. The remains are the best-preserved hominins of this age found anywhere outside of Africa.

13. The Dmanisi Hominins The most complete specimen has a less robust and thinner browridge, a projecting lower face, and a large upper canine. All three Dmanisi crania have small cranial capacities. A number of stone tools, similar to Olduwan industry from Africa, have been recovered at Dmanisi. Remains from four individuals allows comparisons with H. erectus from other areas

14. Dmanisi Diagnostic Characteristics Estimated height ranging from ca 4 feet 9 inches to 5 feet 5 inches, smaller than full H. erectus specimens from East Africa or Asia Body proportions, however, similar to H. erectus (and H. sapiens) and different from earlier hominins

15. Possibilities Raised by the Dmansi Discoveries First hominins to leave Africa were small-bodied early form of H. erectus, with smaller brains than later forms and carrying a typical African Oldowan stone tool culture These hominins had none of the adaptations hypothesized to be essential to hominin migration: tall and relative large brains Perhaps two migrations out of Africa at the time: small-brained, short-statured Dmanisi hominins and large, robust body build of H. erectus populations of Java and China

16. Homo Erectus from Indonesia • Six sites in eastern Java, dating from 1.6 mya to 1 mya, during the Early to Middle Pleistocene. • The Ngandong individuals date from 27,000 ya. • Homo erectus Soloiensus (“Solo man”) formerly classified as Homo Sapiens

17. Homo erectus from China 40 male and female adults and children near Beijing, at Zhoukoudian, excavated beginning in 1920’s. 14 skullcaps, other cranial pieces, more than 100 isolated teeth, and scattering of postcranial remains Formerly called “Peking Man” or Homo erectus Pekinensis

18. European specimens • Atapuerca region in northern Spain, 1.2 mya • partial jaw with few teeth;closely resembles Dmanisi fossils; simple flake tools and animal bones • Gran Dolina, dated to appx 850,000-780,000 ya • Assigning the fossils to a particular species is problematic, based on the fragmentary nature of the remains • Spanish paleoanthropologists place these hominins into a species called Homo antecessor

19. Homo erectus Timeline