1. Chapter 10 Hominid Origins
The Bipedal Adaptation
Early Hominids in the Plio-Pleistocene
The East African Rift Valley
The Earliest East African Hominids
Australopithecus from East Africa
Early Homo

2. Chapter 10 Hominid Origins
Central Africa
South African Sites
Interpretations: What Does It All Mean
Continuing Uncertainties
Putting It All Together
Interpreting the Interpretations

3. The Bipedal Adaptation
Efficient bipedalism among primates is found only among hominids.
All the major structural changes required for bipedalism are seen in early hominids from East and South Africa.
Some researchers believe these early humans also spent considerable time in the trees.

4. The East African Rift Valley
Valley associated with mountain building, faulting and volcanic activity over several million years.
Early sediments were thrown to the surface where they were discovered.
Volanic sediments make it possible to date the sites.
Dating provides information about the chronology of early human evolution.

5. Earliest Traces of East African Hominids
Tugen Hills - Discovered in 2000, the form has been dubbed “Millennium Man”.
Middle Awash - Early fossils first described in Dating places the fossils in the late Miocene.

6. Ardipithecus from Aramis
Dated at 4.4 million years old, oldest collection of hominids discovered.
The remains provide anatomical evidence of bipedalism.
Excavators suggested they be assigned to a new genus and species, Ardipithecus ramidus.

7. Astralopithecus From East Africa
Dating from 4.2 to 1.4 m.y.a. these are included in the genus Australopithecus.
Fossilized hominid footprints were found in an ancient volcanic bed.
Despite agreement that they were bipedal, some researchers feel they were not bipedal in the same way as modern humans.

8. Australopithecus afarensis from Laetoli and Hadar
Several hundred specimens representing 60 to 100 individuals have been removed.
More primitive than other australopithecine fossils from South or East Africa:
Teeth - canines are large and pointed
Small brain

9. Early Homo
The earliest appearance of Homo may be as ancient as the robust australopithecines.
Leakey named these specimens Homo habilis ("handy man")
H. habilis differs from Australopithecus in cranial cavity and dental proportions.

10. Steps in Interpreting Fossil Sites
Selecting and surveying sites.
Excavating and recovering fossil hominids.
Designating individual finds with specimen numbers for clear reference.
Cleaning, preparing, studying and describing fossils.

11. Steps in Interpreting Fossil Sites
Comparing with other fossil material.
Comparing fossil variation with known ranges of variation.
Assigning taxonomic names to fossil material.

12. Subsets of Fossil Data Set I. Basal hominids (6.0-4.4 m.y.a.)
Set II. Early primitive Australopithecus ( m.y.a.)
Set III. Later, more derived Australopithecus ( m.y.a.)
Set IV Early Homo ( m.y.a.)