1. How Did Humans Evolve?
Some Early Primate Adaptations for Life in Trees Were Inherited by Humans
The Oldest Hominid Fossils Are from Africa
The Earliest Australopithecines Could Stand and Walk Upright
Several Species of Australopithecus Emerged in Africa
The Genus Homo Diverged from the Australopithecines 2.5 Million Years Ago

2. The Evolution of Homo Was Accompanied by Advances in Tool Technology
Neanderthals Had Large Brains and Excellent Tools
Modern Humans Emerged Only 150,000 Years Ago
Several Waves of Hominids Emigrated from Africa

3. The Evolutionary Origin of Large Brains May Be Related to Meat Consumption
The Evolutionary Origin of Human Behavior Is Highly Speculative
The Cultural Evolution of Humans Now Far Outpaces Biological Evolution

4. Primates Primates include tarsiers, lemurs, monkeys, apes, and humans
Figure 17-12, p. 332 illustrates representative primates…

5. Figure: 17-12
Title:
Representative primates
Caption:
The (a) tarsier, (b) lemur, and (c) lion-tail macaque monkey all have relatively flat faces, with forward-looking eyes providing binocular vision. All also have color vision and grasping hands. These features, retained from the earliest primates, are shared by humans.

6. Figure: part a
Title:
Representative primates part a
Caption:
The (a) tarsier, (b) lemur, and (c) lion-tail macaque monkey all have relatively flat faces, with forward-looking eyes providing binocular vision. All also have color vision and grasping hands. These features, retained from the earliest primates, are shared by humans.

7. Figure: part b
Title:
Representative primates part b
Caption:
The (a) tarsier, (b) lemur, and (c) lion-tail macaque monkey all have relatively flat faces, with forward-looking eyes providing binocular vision. All also have color vision and grasping hands. These features, retained from the earliest primates, are shared by humans.

8. Figure: part c
Title:
Representative primates part c
Caption:
The (a) tarsier, (b) lemur, and (c) lion-tail macaque monkey all have relatively flat faces, with forward-looking eyes providing binocular vision. All also have color vision and grasping hands. These features, retained from the earliest primates, are shared by humans.

9. Early Primates Were Adapted for Life in Trees
Some of these adaptations were inherited by humans
Large, forward-facing eyes with overlapping fields of view (allowed accurate depth perception)
Color vision
Grasping hands
Enlarged brain (facilitated hand-eye coordination and complex social interactions)

10. The Oldest Hominid Fossils Are from Africa
Hominids include humans and extinct humanlike primates
The oldest known hominid fossils are between 6 and 7 million years old

11. The Oldest Hominid Fossils Are from Africa
Sahelanthropus tchadensis lived more than 6 million years ago
Exhibits human-like and ape-like characteristics
See Figure 17-13, p. 333…

12. Figure: 17-13
Title:
The earliest hominid
Caption:
This nearly complete skull of Sahelanthropus tchadensis, which is more than 6 million years old, is the oldest hominid fossil yet found.

13. The Oldest Hominid Fossils Are from Africa
Ardipithecus ramidus and Orrorin tugenensis lived between 4 million and 6 million years ago
Knowledge of these earliest hominids is limited - few specimens have been found

14. The Oldest Hominid Fossils Are from Africa
The first well-known hominid line, the australopithecines, arose about 4 million years ago
See Figure 17-14, p. 334…

15. Figure: 17-14
Title:
A possible evolutionary tree for humans
Caption:
This hypothetical family tree shows facial reconstructions of representative specimens. Although many paleontologists consider this to the most likely human family tree, there are several alternative interpretations of the known hominid fossils. Fossils of the earliest hominids are scarce and fragmentary, so the evolutionary relationship of these species to later hominids remains unknown.

16. The Australopithecines
The earliest australopithecines possessed knee joints that permitted bipedal (upright, two-legged) locomotion
4 million year old fossilized footprints confirm that early australopithecines sometimes walked upright

17. The Australopithecines
An upright stance was significant in the evolution of hominids because it freed their hands from use in walking

18. The Australopithecines
Several species of Australopithecus have been identified from fossils
Australopithecus anamensis
Australopithecus afarensis – believed to have given rise to:
A. africanus
A. robustus
A. boisei
All australopithecines were extinct by 1.2 million years ago

19. The Genus Homo
The genus Homo diverged from the australopithecine line 2.5 million years ago
See Figure 17-14, p. 334 for a possible evolutionary tree for humans…

20. Figure: 17-14
Title:
A possible evolutionary tree for humans
Caption:
This hypothetical family tree shows facial reconstructions of representative specimens. Although many paleontologists consider this to the most likely human family tree, there are several alternative interpretations of the known hominid fossils. Fossils of the earliest hominids are scarce and fragmentary, so the evolutionary relationship of these species to later hominids remains unknown.

21. The Genus Homo Homo habilis appeared 2.5 million years ago
Bodies and brains were larger than australopithicenes
Retained apelike long arms and short legs

22. The Genus Homo Homo ergaster appeared 2 million years ago
Limb proportions were more like those of modern humans

23. The Genus Homo
Homo ergaster is believed by many to be the common ancestor of:
H. erectus (first hominid species to leave Africa approximately 1.8 million years ago)
H. heidelbergensis
Some migrated to Europe and gave rise to H. neanderthalensis
Those remaining in Africa gave rise to H. sapiens (modern man)

24. Advances in Tool Technology
Hominid evolution is closely tied to the development of tools
Homo habilis produced fairly crude chopping tools that were unchipped on one end to hold in the hand
See Figure 17-15(a), p. 336 to observe an example of a hand axe…

25. Homo habilis Copyright © 2005 Pearson Prentice Hall, Inc.
Figure: part a
Title:
Representative hominid tools part a Homo habilis
Caption:
(a) Homo habilis produced only fairly crude chopping tools called hand axes, usually unchipped on one end to hold in the hand.
Copyright © 2005 Pearson Prentice Hall, Inc.

26. Advances in Tool Technology
Homo ergaster produced finer tools that were typically sharp all the way around the stone
Some of these may have been tied to spears
See Figure 17-15(b), p. 336 to observe examples of H. ergaster tools…

27. Homo ergaster Figure: 17-15 part b Title:
Representative hominid tools part b Homo ergaster
Caption:
(b) Homo ergaster manufactured much finer tools. The tools were typically sharp all the way around the stone; at least some of these blades were probably tied to spears rather than held in the hand.

28. Advances in Tool Technology
Homo neanderthalensis produced exceptionally fine tools with extremely sharp edges made by flaking off tiny bits of stone
See Figure 17-15(c), p. 336 to observe examples of H. neanderthalensis tools…

29. Homo neanderthalensis
Figure: part c
Title:
Representative hominid tools part c Homo Neanderthal
Caption:
(c) Neanderthal tools were works of art, with extremely sharp edges made by flaking off tiny bits of stone. In comparing these weapons, note the progressive increase in the number of flakes taken off the blades and the corresponding decrease in flake size. Smaller, more numerous flakes produce a sharper blade and suggest either more insight into tool making, more patience, finer control of hand movements, or perhaps all three.

30. The Neanderthals
Neanderthals lived in Europe from 150,000 to 30,000 years ago
They were heavily muscled, had brains slightly larger than modern humans, walked fully erect, and constructed finely crafted stone tools

31. The Neanderthals
Neanderthals were once believed to be a variety of H. sapiens; however, molecular evidence indicates that Neanderthals are a separate species

32. Modern Humans Homo sapiens appeared in Africa about 150,000 years ago
European and Middle Eastern H. sapiens appeared about 90,000 years ago and were known as Cro-Magnons

33. Cro-Magnons
Cro-Magnons had domed heads, smooth brows, and prominent chins
30,000-year-old Cro-Magnon artifacts include:
Bone flutes
Ivory sculptures
Evidence of elaborate burial ceremonies
See Figure 17-16, p. 337…

34. Figure: 17-16
Title:
Paleolithic burial
Caption:
This 24,000-year-old grave shows evidence that Cro-Magnon people ritualistically buried their dead. The body was covered with a dye known as red ocher, then buried wearing a headdress made of snail shells and with a flint tool in its hand.

35. Cro-Magnons
Unlike their predecessors, Cro-Magnons created remarkable cave paintings that made use of sophisticated artistic techniques
See Figure 17-17, p. 337…

36. Figure: 17-17
Title:
The art of Cro-Magnon people
Caption:
Cave paintings by Cro-Magnons have been remarkably preserved by the relatively constant underground conditions of a cave in Lascaux, France.

37. Cro-Magnons and Neanderthals Lived Side by Side
Cro-Magnons coexisted with Neanderthals in Europe and the Middle East for as many as 50,000 years
It is not known why the Neanderthals became extinct

38. Several Waves of Hominids Emigrated from Africa
Two hypotheses have been proposed for the evolution of Homo sapiens
“African replacement” hypothesis
“Multiregional origin” hypothesis

39. “African Replacement” Hypothesis
Members of the genus Homo made repeated long-distance migrations out of Africa beginning 1.8 million years ago
H. sapiens emerged from Africa about 150,000 years ago and spread across the Near East, Europe, and Asia

40. “African Replacement” Hypothesis
The dispersing H. sapiens populations replaced all other hominids
See Figure 17-18(a), p. 339…

41. African Replacement Hypothesis
The spread of Homo
erectus began at least
1.8 million years ago
Homo sapiens' expansion
began around 100,000
years ago
Figure: part a
Title:
Competing hypotheses for the evolution of Homo sapiens part a
Caption:
(a) The "African replacement" hypothesis suggests that H. sapiens evolved in Africa, then migrated throughout the Near East, Europe, and Asia, displacing the other hominid species that were present in those regions.

42. “Multiregional Origin” Hypothesis
H. erectus emerged from Africa 1.8 million years ago and spread across the Near East, Europe, and Asia
Continued migrations and interbreeding occurred among widespread H. erectus populations

43. “Multiregional Origin” Hypothesis
Regional populations of H. erectus evolved into H. sapiens
See Figure 17-18(b), p. 339…

44. Multiregional Hypothesis
Regional populations
of Homo erectus
evolved into
Homo sapiens while
intermingling with
one another
Figure: part b
Title:
Competing hypotheses for the evolution of Homo sapiens part b
Caption:
(b) The "multiregional" hypothesis suggests that populations of H. sapiens evolved in many regions simultaneously from the already widespread populations of H. erectus. Question Paleontologists recently discovered fossil hominids with features characteristic of modern humans in 160,000-year-old sediments in Africa. Which hypothesis does this new evidence support?

45. The Evolutionary Origin of Large Brains
Highly developed brains may have evolved in response to increasingly complex social interactions, such as the cooperative hunting of large game

46. The Evolutionary Origin of Large Brains
If the distribution of this group-hunted meat was best accomplished by individuals with large brains, then natural selection may have favored such individuals

47. The Cultural Evolution of Humans
Human evolution has come to be dominated by cultural evolution, the transmission of learned behaviors from generation to generation

48. The Cultural Evolution of Humans
The evolutionary success of humans is the result of cultural evolution and a series of technological revolutions
The development of tools
The agricultural revolution
The industrial revolution

49. The Cultural Evolution of Humans
Human cultural evolution and the accompanying increases in human population have resulted in humans becoming an important agent of natural selection with respect to other life forms

50. The Cultural Evolution of Humans
In the words of Stephen Jay Gould, “We may not be suited for our role as stewards of life’s continuity on Earth, but here we are”