1. Chapter 9
The Earliest Dispersal of the Genus Homo: Homo erectus and Contemporaries

3. Left: Homo Erectus (1mya) Center: Australopithicus afarensis (2
Left: Homo Erectus (1mya) Center: Australopithicus afarensis (2.5mya) Right: Homo Neandertalensis (100,000-32,000ya)

5. Homo erectus
Discoveries from East Africa have established Homo erectus by 1.8 m.y.a.
Some researchers see anatomical differences between the African and Asian discoveries.
They place African fossils into the Homo ergaster species.
Analyses show that H. erectus/ergaster represents closely related species and possibly geographical varieties of a single species

6. BECOMING HUMAN PART II
NOVA

7. First Dispersal of the Hominins
Close to 2 million years ago, hominins expanded out of Africa into other areas of the Old World.
Since the early hominin fossils have been found only in Africa, it seems that hominins were restricted to this continent for as long as 5 million years.

8. First Dispersal of the Hominins
After 2 mya, there’s less diversity in these hominins than in their pre-australopith and australopith predecessors.
There is universal agreement that the hominins found outside of Africa are members of genus Homo.
Homo erectus is the species for which there is the most evidence.

9. Homo erectus – A New Kind of Hominin
The first hominin to expand into new regions of the Old World.
As a species, H. erectus existed over 1 million years.
We can understand its success as a hominid species based on behavioral capacities (i.e.) more elaborate tool use) and physical changes (i.e. larger).

10. Grade
H.erectus hominins represent a different grade of evolution than their African predecessors.
Grade refers to a grouping of organisms sharing a similar adaptive pattern.
Grade implies nothing directly about shared ancestry, but implies general adaptive aspects of a group of animals

11. Morphology of Homo erectus
Living in different environments over much of the Old World, H. erectus populations shared several common physical traits including…

12. Body Size
Adult weight >100 lbs, average adult height of ca. 5 feet 6 inches
Sexually dimorphic, weight and height varied according to sex
Increased robusticity (heavily built body) that dominated hominin evolution until anatomically modern H. sapiens

13. Brain Size Cranial capacities 700 cm3 to 1250 cm3
Homo Sapien
Skulls
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
 1. Australopithecus afarensis  
2. Australopithecus africanus  
3. Homo habilis  
4. Homo erectus
5. Homo Neandertalensis

14. 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

15. Homo Erectus finds Africa, Asia, Indonesia, Europe

16. 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

17. TURKANA BOY a.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.

18. TURKANA BOY Nariokotome 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.

19. 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 thick cranial bones in Asian H. erectus.

20. 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

21. 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

23. 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

24. 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.

25. 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

26. 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