1. The Story of Human Evolution
From Primates to Homo sapiens sapiens

2. The Myth of the Biggest and Bestest
“survival of the fittest”
Our cultural problem
Stephen Jay Gould
history of biological life = “proliferation of enormously varied designs subsequently restricted to a few highly successful, but imperfect, forms”
“Our world is not an optimal place fine-tuned by omnipotent forces of selection. It is a quirky mass of imperfections, working well enough (often admirably); a jury-rigged set of adaptations, built of curious parts made available by past histories in different contexts.”
ladder imagery
(what else is going on in this picture?)

3. Considering Evolution
Natural Selection:
an evolutionary process through which factors in the environment exert pressure that favors some individuals over others to reproduce the next generation of the group
this pressure acts on phenotype (genes plus environment), not genotype (DNA, genetic makeup)

4. Never exact match between phenotype
and genotype
Never exact fit between organism and
environment: dynamism
Biological plasticity of individuals

5. Old world monkeys (eg baboons), and apes.
Note: there are prosimians (eg lemurs), new world monkeys (eg spider monkey,
Old world monkeys (eg baboons), and apes.
Apes include gibbons, orangutans, chimps, bonobos, gorillas and humans. 99% of human DNA shared with chimps (study in Nature, )
Fig 8-2

6. Primate Tendencies Grasping and opposable thumbs Smell  sight
mouth  hand
brain complexity increases
parental investment increases
Sociality increases
Snarling mandrill

7. Gorilla family
gibbon
humans
chimp

8. Primate Social Behavior
Wide range of social behaviors and types of social organization for different species—a few examples follow
Male led (chimps), female led (bonobos),
Savanna baboons—highly complex multi male and female troops
Only ape that is monogamous—gibbon
Apes that display wide range of sexual behavior—bonobos

9. Overview of Hominid Evolution
Australopithecines (Lucy) 5-2 million years ago (mya)
Gracile
Robust
Homo habilis (3-2 mya)
Homo erectus (1.5 – 0.4 mya, or ?12,000ya)
Homo sapiens (.02 mya, 200k-present)
Homo sapiens neanderthalensis 60k
Homo sapiens sapiens (dif places different times) 200,000k

10. Key Ideas Feedback and inadvertency Shifts in lifestyles/diets
Bipedalism
Brain Size/complexity
Tools, Language and Culture
Shifts in lifestyles/diets
Types of evolutionary change
Graduated
Punctuated Equilibrium

11. Chimp Skeleton
Human skeleton
Fig 9-5

12. Characteristics of Australopithecines
General Characteristics
Skeleton: Bipedal, not fully upright
Brain only slightly bigger than a chimp’s.
Smaller canines than a chimp, bigger molars
Hands: precision and power grip.
Likely savanna adaptation—likely vegetarian
Robustus has extreme savanna adaptation
Recent debate re: degree of bipedality, habitat type
not fully a “knuckle-walker” like gorillas, but could walk on two feet..early A’s (like lucy) stil had stiff wrists like apes to allow knuckle walking, make tool making difficult, later A’s have a more flexible wrist…hence some tool making

13. The skeleton of Lucy,
notice the bipedality
along with a relatively
small cranium and
chimp-like skull

14. Australopithecus
sites in Africa
Fig 9-8

15. On Bipedalism: Australopithecines take steps…
Disadvantages?
visible to predators
exposed underbelly
slow
Advantages?
Man the hunter? (NO!)
Woman the food carrier
Infant carry
Artist’s rendering of A. africanus
(interesting way in which racial ideas intervene)

16. Why Be Bipedal? Advantages, con’d Efficient food procurement?
See farther?
Efficient long distance travel?
Cool brain?
All of the above?
Artist’s rendering of A. africanus

17. Effect of Bipedality: inadvertency in human evolution, 2 examples
1. Hands are free
tool use
increasing tool use leads to increasing brain size and complexity
2. the birth canal problem and its consequence
(evolution at work)

18. Pelvis structure of Humans and Chimps
Fig 9-6

19. From Australopithecus to Homo: moving towards culture
Homo habilis (the handy man!)—(3-2 mya)
Brain
larger: 650 cm2
area of skull indicates language
Body
more gracile

20. Robust and Habilis Hung Out
Robust australopithecines (A. boisei) and H. habilis co-existed for at least 1/2 million years
What happened? Why did Australopithecines die out?
Competitive exclusion?
Niche divergence? (natural selection is environment specific)

21. Homo Erectus Lived 1.5 to .4 mya
1 mya as single spp.
Example of punctuated equilibrium
Significant increase in brain size:
Fully erect/bipedal

22. Homo Erectus Lifestyle, con’d
First use of fire
cook
heat
protection against predators
thaw out carcasses
Evidence of “culture” or symbolic activity
complexity of tools
cooperative hunting
red ochre

23. Illustration of an Erectus cooperative elephant hunt

24. Homo Erectus lifestyle, con’d
Migration out of Africa, first time in H. history

25. Modern Humans, Early Homo sapiens sapiens
Timing of first evidence
Africa: more than 100,000 ya
Asia: 60,000 ya
Europe: 35,000 ya
Australia: 40,000 ya
Americas: 20,000 ya

26. Early Modern H. s. s. Cultural changes Art (Cro Magnon) tools
standardization
distinct sets for distinct areas indicating cultural diversity

30. Neanderthals Debate over where they belong in evolutionary story
The “cave man” …with a large brain
Robust skeletons
Latest research

31. Recent Finding from Indonesia
2004: Tiny Homo floresiensis, 3 feet tall, resembling H. erectus in some ways, but found with evidence of highly developed culture, boats, etc
Endemic island dwarfing (happens to a lot of other large mammals on islands)
Small brain, lots of smartness…
Co-habited earth with modern humans—these finds are from k years ago
Cultural groups in the area have stories/legends about “small people”
Most recent debates: some researchers argue that these are just small modern humans

32. Theories of the Origins of Modern Humans
Two competing theories:
Multiregional
Replacement/Out of Africa
Multiregional/Local Continuity Theory
evidence
apparently intermediate fossil forms between H. erectus and modern humans in each location (Africa, Asia, Europe)

34. Theories of the Origins of Modern Humans, con’d
Replacement/Out of Africa-Mitochondrial Eve Theory
evidence
earliest H. sapiens sapiens found in Africa
Mitochondrial and nuclear DNA
all humans closely related, genes diverged from single recent African origin, at about 100 kya
Neanderthal mtDNA is not more similar to European than any other

36. The Most Logical Theory: A Mix of the two
Independent evolution unlikely 3x
Interbreeding/gene flow likely, migration and movement all along
The human thing
migration
interbreeding
Implications for understanding race

37. Questions to ask about your skulls
What species is it?
When did it live?
What are its key skeletal and other (?culture, etc) features
Why is it significant?
Where does it fit on evolutionary tree leading to Homo sapiens sapiens