1. The Evolution of Primates
Chapter 22

2. Learning Objective 1
What structural adaptations do primates have for life in treetops?

3. Primates (1) Placental mammals Five grasping digits
evolved from arboreal shrewlike mammals
Five grasping digits
including opposable thumb or toe

4. Five Grasping Digits

5. (a) Lemur (Eulemur mongoz)
Hand
Foot
Figure 22.1: Right hands and feet of selected primates.
(Figures not drawn to scale.) (Adapted from A. H. Schultz, The Life of Primates, Weidenfeld & Nicholson, London, 1969.)
(a) Lemur (Eulemur mongoz)
Fig. 22-1a, p. 467

6. (b) Tarsier (Tarsius spectrum)
Hand
Foot
Figure 22.1: Right hands and feet of selected primates.
(Figures not drawn to scale.) (Adapted from A. H. Schultz, The Life of Primates, Weidenfeld & Nicholson, London, 1969.)
(b) Tarsier (Tarsius spectrum)
Fig. 22-1b, p. 467

7. (c) Woolly spider monkey (Brachyteles arachnoides)
Hand
Foot
Figure 22.1: Right hands and feet of selected primates.
(Figures not drawn to scale.) (Adapted from A. H. Schultz, The Life of Primates, Weidenfeld & Nicholson, London, 1969.)
(c) Woolly spider monkey
(Brachyteles arachnoides)
Fig. 22-1c, p. 467

8. (d) Gorilla (Gorilla gorilla)
Hand
Foot
Figure 22.1: Right hands and feet of selected primates.
(Figures not drawn to scale.) (Adapted from A. H. Schultz, The Life of Primates, Weidenfeld & Nicholson, London, 1969.)
(d) Gorilla (Gorilla gorilla)
Fig. 22-1d, p. 467

9. Primates (2) Long, slender limbs Eyes located in front of head
move freely at hips and shoulders
Eyes located in front of head

10. Learning Objective 2 What are the three suborders of primates?
Give representative examples of each

11. Suborders of Primates Prosimii Tarsiiformes Anthropoidea (anthropoids)
lemurs, galagos, and lorises
Tarsiiformes
tarsiers
Anthropoidea (anthropoids)
monkeys, apes, and humans

12. Primate Evolution

13. Suborder Tarsiiformes Common primate ancestor
Suborder Prosimii
Suborder Tarsiiformes
Suborder Anthropoidea
Hominoids (Anthropoids)
Gorillas
Humans
Gibbons
New World monkeys
Old World monkeys
Lemurs
Tarsiers
Orangutans
Chimpanzees 3 2 1
Figure 22.2: Primate evolution.
This branching diagram, called a cladogram, shows evolutionary relationships among living primates, based on current scientific evidence. The nodes (circles) represent branch points where a species splits into two or more lineages. ●1 The divergence of orangutans from the ape/hominid line occurred some 12 mya to 16 mya. ●2 Gorillas separated from the chimpanzee/hominid line an estimated 8 mya, and ●3 the hominid (human) lineage diverged from that of chimpanzees about 6 mya. (Figures not drawn to scale.)
Common hominoid ancestor
Common anthropoid ancestor
Common primate ancestor
Fig. 22-2, p. 468

14. KEY CONCEPTS
Humans are classified in the order Primates, along with lemurs, tarsiers, monkeys, and apes
This classification is based on close evolutionary ties

15. Learn more about primate evolution by clicking on the figure in ThomsonNOW.

16. Learning Objective 3
What is the difference between anthropoids, hominoids, and hominids?

17. Anthropoids Include monkeys, apes, and humans Branched into 2 groups:
New World monkeys
Old World monkeys

18. New World and Old World Monkeys

19. Hominoids Include apes and humans 4 modern genera of apes:
arose from Old World monkey lineage
4 modern genera of apes:
gibbons
orangutans
gorillas
chimpanzees

20. Ape Evolution

21. (a) Fossils of Aegyptopithecus, a fairly primitive anthropoid, were discovered in Egypt.
Figure 22.5: Ape evolution.
(Figures not drawn to scale.)
(c) Dryopithecus, a more advanced ape, may have been ancestral to modern hominoids.
Fig. 22-5a/c, p. 470

22. Apes

23. Figure 22.6: Apes.
Fig. 22-6a, p. 471

24. Figure 22.6: Apes.
Fig. 22-6b, p. 471

25. Figure 22.6: Apes.
Fig. 22-6c, p. 471

26. Figure 22.6: Apes.
Fig. 22-6d, p. 471

27. Hominids
Humans and their ancestors

28. KEY CONCEPTS
The study of living primates provides clues to help scientists reconstruct the adaptations and lifestyles of early primates, some of which were ancestors of humans

29. Learning Objective 4
What are the skeletal and skull differences between apes and hominids?

30. Hominid Skeletons
Adaptations for standing erect and walking on two feet
complex curvature of the spine
short, broad pelvis
foramen magnum at base of skull
first toe aligned with other toes

31. Gorilla and Human Skeletons

32. Shorter, broader pelvis (front view)
Simply curved spine
Foramen magnum at the center base of skull
Complex curvature of human spine
Foramen magnum at the center rear of skull
Tall, narrow
pelvis (front view)
Shorter, broader pelvis (front view)
Figure 22.7: Gorilla and human skeletons.
When gorilla and human skeletons are compared, the skeletal adaptations for bipedalism in humans become apparent.
First toe not aligned with others
First toe not opposable, and all toes aligned
Gorilla skeleton
Human skeleton
Fig. 22-7, p. 472

33. Human Skeleton Human skull lacks pronounced supraorbital ridge
flatter than ape skulls in front
has a pronounced chin
larger brain than apes
jaw structure with teeth arranged in U shape

34. Human Skull

35. Supraorbital ridge Incisors Rectangular shape Fig. 22-8a, p. 473
Figure 22.8: Gorilla and human heads.
Incisors
Rectangular shape
Fig. 22-8a, p. 473

36. Incisors U-shape Fig. 22-8b, p. 473
Figure 22.8: Gorilla and human heads.
Incisors
U-shape
Fig. 22-8b, p. 473

37. KEY CONCEPTS
The human brain did not begin to enlarge to its present size and complexity until long after human ancestors had evolved bipedal locomotion

38. Learn more about monkey, gorilla, and human skeletons by clicking on the figure in ThomsonNOW.

39. Learning Objective 5
Describe the following early hominids: Sahelanthropus, Orrorin, Ardipithecus ramidus, and Australopithecus anamensis, A. afarensis, and A. africanus

40. Sahelanthropus Hominid Evolution began in Africa Sahelanthropus
6 to 7 million years ago
Sahelanthropus
small brain
face and teeth had many characteristics of larger brained human ancestors

41. Orrorin Early hominid Orrorin about 6 mya
probably walked upright and was bipedal
based on fossil leg bones

42. Australopithecines (1)
Include
Ardipithecus and Australopithecus species
Australopithecus species
bipedal (a hominid feature)

43. Australopithecines (2)
Ardipithecus ramidus
about 5.8 mya to 5.2 mya
Australopithecus anamensis
Australopithecus afarensis
Australopithecus africanus

44. Genus Homo
Genus Australopithecus contains the immediate ancestors of genus Homo

45. Possible Evolutionary Relationships

46. Millions of years ago (mya)
H. sapiens
H. neanderthalensis
Archaic H. sapiens
H. erectus
A. boisei
A. robustus
H. ergaster
H. habilis
A. aethiopicus ?
Millions of years ago (mya)
A. africanus
A. afarensis
Figure 22.9: One interpretation of human evolution.
This figure does not include hominid fossils earlier than Ardipithecus. Dashed lines show possible evolutionary relationships.
A. anamensis
A. ramidus
Ardipithecus
Australopithecus
Homo
Fig. 22-9, p. 473

47. Millions of years ago (mya)
H. sapiens
H. neanderthalensis
Archaic H. sapiens
H. erectus
H. ergaster
H. habilis
Homo
A. boisei
A. robustus
A. aethiopicus
A. africanus
A. afarensis
A. anamensis
Australopithecus ?
Millions of years ago (mya)
Figure 22.9: One interpretation of human evolution.
This figure does not include hominid fossils earlier than Ardipithecus. Dashed lines show possible evolutionary relationships.
A. ramidus
Ardipithecus
Stepped Art
Fig. 22-9, p. 473

48. Learning Objective 6
Distinguish among the following members of genus Homo: H. habilis, H. ergaster, H. erectus, H. neanderthalensis, and H. sapiens

49. Homo habilis
Earliest known hominid with some human features lacking in australopithecines
including slightly larger brain
H. habilis fashioned crude tools from stone

50. Homo erectus (1) Larger brain than H. habilis
made more sophisticated tools
may have worn clothing, built fires, lived in caves or shelters

51. Pronounced supraorbital ridge
Receding forehead
Figure 22.10: Homo erectus skull from China.
The reconstructed parts are white. Note the receding forehead, pronounced supraorbital ridge, and projecting face and jaws.
Projecting face/jaws
Fig , p. 475

52. Homo erectus (2) Fossils may actually be 2 species Homo ergaster
earlier African species
gave rise to archaic H. sapiens
H. erectus
later Asian offshoot
may be evolutionary dead end

53. Archaic Homo sapiens
Regionally diverse descendants of H. erectus or H. ergaster
in Africa, Asia, and Europe
about 400,000 to 200,000 years ago
Brains about same size as our brains
skulls retained some ancestral characters
rich and varied cultures

54. Neandertals 230,000 to 30,000 years ago Short, sturdy builds
receding chins and foreheads
heavy supraorbital ridges and jawbones
large front teeth
nasal cavities with triangular bony projections

55. Neandertal Tools

56. Homo sapiens Anatomically modern humans
in Africa about 195,000 years ago
Only members of genus Homo remaining
about 30,000 years ago

57. Cro-Magnons
Ancient Homo sapiens in Europe

58. KEY CONCEPTS
Fossil evidence indicates that the earliest hominids (human ancestors) evolved in Africa and shared many features with their apelike ancestors

59. Learn more about Homo skulls by clicking on the figure in ThomsonNOW.

60. Learning Objective 7
Discuss the origin of modern humans

61. Origin of Modern Humans (1)
Out-of-Africa Hypothesis
Modern H. sapiens arose in Africa
migrated to Europe and Asia
displaced more primitive humans living there
Supported by recent fossil discoveries and molecular data

62. Origin of Modern Humans (2)
Multiregional hypothesis
Modern humans originated as separately evolving populations of H. erectus in Africa, Asia, and Europe
Populations occasionally interbred, preventing complete reproductive isolation

63. KEY CONCEPTS
Human culture began when human ancestors started making stone tools

64. Learning Objective 8
What is the impact of human culture on the biosphere?

65. Human Impacts Large human brain size
transmission of knowledge from one generation to the next
2 significant advances in human culture
development of agriculture
Industrial Revolution