1. The Evolution of Humans

2. The Evolution of Humans An Evolutionary Play in Five Acts
Act one: The Cro Magnons and the Neanderthals
Act two: The Great Leap Forward
Act three: Early Homo
An interlude
Act four: The Australopithecines
Act five: The First Steps

3. The Evolution of Humans
The Ecological Theatre
The Stage: East Africa...

4. The Evolution of Humans

5. The Evolution of Humans
The Ecological Theatre
The Stage: East Africa
The Setting: A time of unrest...

6. The Evolution of Humans
The Ecological Theatre
The Stage: East Africa
The Setting: A time of unrest...
Geologically…
The rift zone - uplifts, rifting, volcanoes (an "aulacogen")

7. The Evolution of Humans

8. The Evolution of Humans

9. The Evolution of Humans
Is 7 million years enough?

10. The Evolution of Humans
The Ecological Theatre
The Stage: East Africa
The Setting: A time of unrest...
Geologically…
The rift zone - uplifts, rifting, volcanoes
Climatically…
A series of glaciations
Global climate change
Changes in sea level

11. The Evolution of Humans
Act one: The Cro Magnons and the Neanderthals

12. The Evolution of Humans
What about the Neanderthals?
had been in Europe and the middle east for about years, through several periods of glaciation
presumably evolved separately from homo sapiens, from homo erectus ancestors, in africa at least 250,000 ya

13. The Evolution of Humans
What about the Cro Magnons?

14. The Evolution of Humans The Neanderthals and the Cro Magnons…
Climate change?
Hybridization?
Ecological competition?
“Conquest”?

15. The Evolution of Humans
What about the Cro Magnons?
The cro magnons are BMH - complex tools, large population sizes, social systems, clothing, ornaments, trade…

16. The Evolution of Humans
art, music, rituals, burying the dead, language

17. The Evolution of Humans Act two: The Great Leap Forward

18. The Evolution of Humans Act two: The Great Leap Forward
Homo sapiens sapiens (behaviorally modern humans) appeared sometime between 160 tya and 40 tya
Fossils from East Africa have been described as a new subspecies Homo sapiens idaltu, and dated about 160 tya…
The development of behaviorally modern humans is sometimes referred to as the “Great Leap Forward”...
idaltu was not “behaviorally modern” by any stretch of the imagination, but skull fragments show signs of being handled and altered after death - not cannibalism, so perhaps ritual associated with burial.

19. The Evolution of Humans The Great Leap Forward reasons for the Great Leap Forward…

21. The Evolution of Humans The Great Leap Forward
Due to evolution of a mechanism that allows speech and language?
Characterized by the appearance of...
Use of symbols...
Complex tools...
Innovations in hunting techniques and strategies...
Increased population size, development of social systems...
Houses, boats, long distance trade, ornaments
Art, music, rituals...
eventually…
metallurgy
agriculture
cities, complex social organization, warfare…

22. The Evolution of Humans Act three, scene one: Early Homo
Homo heidelbergensis

23. The Evolution of Humans Act three, scene one: Early Homo
Homo heidelbergensis ( tya)
formerly referred to as “archaic” H. sapiens)
their skeletal characteristics are intermediate between H. erectus and H. sapiens
Homo heidelbergensis appeared first in Africa, then later in Europe and western Asia.
Homo heidelbergensis is thought to be ancestral to Homo neanderthalensis (250 tya - 30 tya) and to Homo sapiens (at least 195 tya - present)

24. The Evolution of Humans Act three, scene one: Early Homo
Homo erectus (1.9 mya mya)
first described in 1891, before the existence of the australopithecines was known
Variously known as Java Man, Peking Man, Turkana Boy…

25. The Evolution of Humans “Peking Man”

26. The Evolution of Humans “Turkana boy”

27. The Evolution of Humans Act three, scene one: Early Homo
Recent interpretations of Homo erectus include two other species (Homo ergaster and Homo antecesor) within Homo erectus
In this view, Homo erectus is a widespread and geographically variable species

28. The Evolution of Humans Act three, scene two: Early Homo
Actors include Kenyanthropus platyops (about 3.5 mya), Homo habilis ( mya), and Homo erectus (1.9 mya tya)
The simple interpretation ignores Kenyanthropus, places Australopithecus afarensis as ancestral to Homo habilis (giving Lucy the honor of being the ancestor of the genus Homo), and places Homo habilis as ancestral to Homo erectus.
A more complex interpretation recognizes Kenyanthropus as having features more like Homo erectus, and places it as ancestral to Homo erectus, leaving Homo habilis as a sterile side branch.

29. The Evolution of Humans

30. The Evolution of Humans
Kenyanthropus platyops and Homo habilis

31. The Evolution of Humans
The interlude…
Morphological
Ecological

32. The Evolution of Humans
Morphological trends during the evolution of hominids:
Morphological features associated with bipedalism:
Foramen magnum directed downward
Pelvis is shorter, flatter, and broader
Pelvic canal expands
Acetabula point downward
Legs longer, arms shorter

33. The Evolution of Humans
Pertinent morphological trends during the evolution of hominids:
Other trends...
Body size increases
Cranial capacity increases
Australopithecus afarensis: 400 ml
Australopithecus africanus: 440 ml
Homo habilis: 600 ml
Homo erectus: 850 ml
Homo heidelbergensis: 1200 ml
Homo sapiens: 1350 ml
Homo neanderthalensis:

34. The Evolution of Humans
Ecological and behavioral trends during the evolution of hominids:
Habitat changes from forest to savanna, associated with changing climate in east Africa, but…
Geological and climate change is complex and does not always correspond to changes in hominids
Social organization - probably small social groups
Development of tool use (in Homo habilis and Homo erectus)
Domestication of fire (probably in Homo erectus)

35. The Evolution of Humans Act four: The Australopithecines:
Australopithecus plays a central role in the phylogeny of hominids. This was the first genus to branch into several species.
The earliest member of this genus is Australopithecus anamensis (4.0 mya).
The immediate descendant of Australopithecus anamensis is Australopithecus afarensis ( mya).
Of the australopithecines, Australopithecus afarensis ("Lucy") is the most famous and best known paleontologically.

36. The Evolution of Humans

37. The Evolution of Humans Act four: The Australopithecines:
Australopithecus afarensis is thought to be ancestral to A. africanus (2.5 mya).
After A. afarensis and A. africanus, several species appear, including a group of 3 to 5 species that are now called the “robust australopithecines” and placed in the genus Paranthropus.

38. The Evolution of Humans Act four: The Australopithecines

39. The Evolution of Humans Act five: The First Steps
A linear sequence of species leads from the divergence from chimps about 7 mya to the appearance of Australopithecus about 4 mya
Sahelanthropus tchadensis (7 mya)
Orrorin tugenensis (6 mya)
Ardipithecus kadabba (5.2+ mya)
Ardipithecus ramidus (4.4+ mya)
These actors exhibit a progression of characteristics that indicate they are part of the main line of hominid evolution
Were they bipedal?

40. The Evolution of Humans
Sahelanthropus
tchadensis