1) Humans diverged from chimpanzees around 6-8 million years ago. While chimps are our closest living relatives, sharing 95% of our DNA, structural differences evolved between humans and apes that allowed humans to walk upright. 2) As humans evolved, our skeletons developed features adapted for bipedalism, such as a more rigid, S-shaped backbone for support and balance, broader chests, and longer necks. Our shoulders also broadened and the shoulder blades moved to the back. 3) The hands of humans became more refined for grasping tools, with an opposable thumb and precision grip, whereas ape hands are adapted for climbing and brachiation with longer

1. Humans vs apes
• Chimps are our closest living
relatives, sharing about 95% of
our DNA.
• So what are the differences
between us and the apes?

2. Chimpanzee-human
divergence
Chimpanzees Humans
6-8
million
years
Hominids or hominins

3. Homonins and Homonids
• Homonin
– A living or fossil
species of the human
lineage.
• Homonid
– The group containing
humans and African
apes (Gorilla,
Chimpanzee and
Bonobo)

4. Class Slides Set 15B
The Upper Body

5. brachiation
and
erect walking
resulted in a number of
structural differences

6. Understanding Physical Anthropology and Archaeology, 9th ed., p. 121
Skeleton of a brachiator (gibbon)

7. 1) THE CHEST IS BROAD AND NARROW IN HUMANS AND
FLATTENED FROM FRONT TO BACK (IN APES THE CHEST IS
FLATTENED AT THE SIDES
2) HUMANS HAVE LONGER COLLAR BONES
3)IN HUMANS THE SHOULDER BLADES LIE ON THE BACK
OF THE CHEST (IN QUADRUPEDS THEY’RE ON THE SIDES
OF THE CHEST
The upper body . . .

9. Human skeleton (Homo sapiens) – bipedal hominid.
Understanding Physical Anthropology and Archaeology, 9th ed., p. 429

10. Spine has become more
massive and rigid, with
fewer vertebrae –
stronger and able to
support an upright torso.

12. Humans developed
an
S-curved backbone
(rather than one
with a simple
curve/arch)
This provides
support and
balance.

14. Human vertebral column (lateral view).
Understanding Physical Anthropology and Archaeology, 9th ed., p. 243

15. Chest has become wider
and more barrel-like

16. Modern human skeleton
Understanding Physical Anthropology and Archaeology, 9th ed., p. 429

18. Shoulders have
broadened

19. Human skeleton (Homo sapiens) – bipedal hominid.
Understanding Physical Anthropology and Archaeology, 9th ed., p. 429

20. Relatively longer necks
have developed

21. Understanding Physical Anthropology and Archaeology, 8th ed., p. 223
Modern human skeleton

22. Humankind Emerging, 7th ed., p. 190

23. The arms and hands . . .

24. The forelimbs of apes
have become
strengthened and
elongated
(relative to the length of the body)

26. Humankind Emerging, 7th ed., p. 240
Homo habilis

27. Understanding Physical Anthropology and Archaeology, 8th ed., p. 223
Modern human skeleton

28. Humankind Emerging, 7th ed., p. 113
Gorilla

30. Hands
become more hand-like . . .

32. Humankind Emerging, 7th ed., p. 174+

33. Power grip –
(“prehensility”)
a grip involving all fingers of the
hand equally, as in grasping a
baseball

35. Precision grip –
(“opposability”)
a grip that involves
opposing the tip of the
thumb to the tips of the
other fingers

39. Hand anatomy.
Understanding Physical Anthropology and Archaeology, 9th ed., p. 435

41. Primate (Macaque) hand
Understanding Physical Anthropology and Archaeology, 8th ed., p. 121

45. The Primates, Time-Life (1974) p. 126
Two-year-old Baboon

48. The Skull
Continue on to Set # 16A