1. Biological Anthropology
The Early Hominids

2. Hominid Species Ardipithecus ramidus Homo habilis Homo erectus
Australopithecus afarensis
Australopithecus africanus
Australopithecus boisei
Australopithecus robustus
Homo habilis
Homo erectus
Homo sapiens

3. Ardipithecus ramidus
A revolutionary find Why “revolutionary”? Let’s see what we know before her…

4. Australopithecus afarensis
1973 – “Johanson’s knee”
First suggestion of bipedalism

5. Figure 11.13
The knees of A. afarensis are more like the knees of modern humans than the knees of chimpanzees. Consider the lower end of the femur, where it forms one side of the knee joint. In chimpanzees, this joint forms a right angle with the long axis of the femur. In humans and australopithecines, the knee joint forms an oblique angle, causing the femur to slant inward toward the centerline of the body. This slant causes the knee to be carried closer to the body’s centerline, which increases the efficiency of bipedal walking.

6. Australopithecus afarensis
1974 – “Lucy”
47 out of 207 bones

7. Australopithecus afarensis
1975 – “First Family”
Over 200 fragments from at least 13 individuals

8. Australopithecus afarensis
1978 – Laetoli footprints
3.6 my BP (K/Ar)
Clear bipedalism
Divergent big toe

9. Australopithecus afarensis
Fully bipedal, but…
Arms longer than legs
Divergent big toe (?)
3.5 – 4.0 ft tall

10. Figure 11.08
Here, Lucy’s skeleton stands beside the skeleton of a modern human female. The parts of the skeleton that have been discovered are shaded. Lucy was shorter than modern females and had relatively long arms and a relatively small brain.

11. Figure 06.06

12. Australopithecus afarensis
Cranial capacity: cc

13. Australopithecus afarensis
Rounded dental arcade (not parabolic)
app. 33% have large canine with diastema
Simian shelf present

14. Figure 11.10a
The teeth and jaws of A. afarensis have several features that are intermediate between those of apes and modern humans. (a) The dental arcade is less U-shaped than in chimpanzees, but less parabolic than in modern humans.

15. Australopithecus afarensis
Ca. 4-3 my BP
Found only in East Africa
No known culture

16. Australopithecus africanus
First find made in 1924 by quarryman M. de Bruyn
Cleaned and identified by Raymond Dart

17. Australopithecus africanus
Dental evidence indicated a juvenile age
“Taung child”

18. Australopithecus africanus
Finds in Southern and Eastern Africa
Dates between app my BP

19. A. africanus: bipedalism
Full biped
Pelvis smaller & upright
Parallel toes
Developed arch in foot

20. A. africanus: dentition
No large canines
No diastema
Simian shelf
V-shape jaw

21. A. africanus: cranial capacity
400 – 600 cc

22. Osteodontokeratic culture
osteo = bone
donto = teeth
keratic = hair, horn
Postulated by Raymond Dart as early culture of Australopithecus africanus
May be the culture of all Australopithecus species

23. Australopithecus boisei Australopithecus robustus
Two very different types of hominids

24. Where were they found? boisei East Africa (Olduvai!) robustus
South Africa

25. What are their dates? boisei ca. 2.5 – 1.0 my BP robustus

26. Cranial capacity
boisei
mean ca. 510 cc
robustus
mean ca. 510 cc

27. Bipedalism
Human-like bipedalism
Smaller in stature

28. dentition Huge jaw Small incisors & canines Large premolars & molars
Parabolic dental arcade
Simian shelf

29. Chewing apparatus
Sagittal crest
No diastema

30. “Dietary Hypothesis” suggests two groups
Gracile
A. afarensis
A. africanus
Robust
A. boisei
A. robustus

33. Dietary Hypothesis
Graciles
Omnivorous diet
Robusts
High fiber diet

34. Figure 05.34a

35. “Ardi” Ardipithecus ramidus
a 4.4 million year old relative?

36. Found in Eastern Africa
First fossils discovered in 1992
Includes a partial skeleton
And remains of at least 35 other individuals

37. An unexpected mix of traits…

38. Ardipithecus locomotion
hands and arms indicate she could climb like a chimp, but walked on her palms (not knuckles)
Chimp skeleton
A. afarensis skeleton
rigid feet are more like an Old World monkey’s than an apes
Ardi
legs and pelvis
indicate that she could move on two legs like a biped

39. Ardipithecus cranial capacity
300 – 350 cc
reconstruction based on CT scans of fossil fragments

40. Ardipithecus dentition
Modern human
Modern chimp
Ardi’s canines are blunt – like a humans
A move away from multi-male, multi-female mating patterns?

41. Ardipithecus dentition
Modern human
Modern chimp
The wear patterns and isotope analysis of teeth suggest a varied vegetarian diet

42. Why is Ardi so “revolutionary”?
Our earliest ancestor may not have looked like a modern chimp
Ardi undermines the “savanna hypothesis”