1. Primate Evolution

2. “Light will be thrown on the origin of man and his history".
When Darwin wrote the Origin of Species, he had only one sentence
about the topic merely saying,
“Light will be thrown on the origin
of man and his history".
In 1859, there was not
a single “human” fossil known
and everything was speculation.

3. Today, we have thousands of hominid fossils and thousands of books and papers on the subject. Still we do not have enough.

4. Though we now know many of the steps along the journey, we are woefully ignorant of the forces that molded our evolution, how much of it was due to
natural selection, adaptations to particular environments; or
sexual selection, traits that females or males chose when selecting their mates; or
genetic drift; traits that occurred by chance mutation in the small human populations?
The search goes on.

5. Here is one story in the long journey to find our ancestors.

6. December 17, 1992
When graduate student Gen Suwa saw a glint among the pebbles in the desert of Ethiopia, he knew immediately it was a “human” molar.

8. Suwa called the team and on hands and knees they scoured the rocks looking for bone fragments.
There ,near the village of Aramis, they knew they had something special , a hominin , older than Lucy—a once in a lifetime discovery. Tim White’s team had done it again.

9. Months and years were to pass
as more pieces were found and
pieced together—
pelvis, leg, ankle, foot,
hand and jaw—
--the rarest of finds,
a partial skeleton of a new “human” fossil.
It was a female and they nicknamed it “Ardi,”
short for Ardipithecus ramidus ;
not only a new species, but a new genus!

10. The White team eventually found over 100 specimens of the new species.
Anthropologist Owen Lovejoy of Kent University said, “This team seems to suck fossils out of the earth.”

11. White and others spent years removing clay from the bones with brushes, syringes, and dental tools.

12. Suwa and Lovejoy made virtual reconstructions of the crushed skull and pelvis, scanning them with micro-computer tomography.
Nine years later ,having mastered the necessary technology , Suwa had reassembled the fragments into a virtual skull. By March of 2009, and the 10th reconstruction, he was satisfied.

13. In Ohio, Lovejoy was finally satisfied that his 14th version of the pelvis was accurate. In October, 2009, they published their results in Science magazine, 20 years after the first discovery.

15. The 47 Authors Authors

16. So where does Ardi fit in the scheme of human evolution
So where does Ardi fit in the scheme of human evolution? The fossils were found in a layer of soil sandwiched between two volcanic layers that are dated radiometrically as 4.4 million years old.
So this puts it

17. But just what did we used to be?
“This is not an ordinary fossil. It’s not a chimp. It’s not a human. It shows us what we used to be,” said Tim White, co-director of the project, a paleontologist at the University of California at Berkeley.
But just what did we used to be?

18. From Apes
To Humans

19. What do we know about the phylogeny of humans?
Human Evolution
What do we know about the phylogeny of humans?

20. The Great Apes

21. Primate Phylogeny

22. Put the following animals in their correct position: chimpanzee, lemur, human, gorilla, orangutan, monkey A B C D E F

23. Primate Traits Nails instead of claws; digits with dermal pads
Prehensile (grasping) hands & feet
Five fingers & toes
Tendency toward complete bony eye orbits
Forward placement of eyes
Opposable toe & thumb
Enlarged cerebral hemispheres
One pair of thoracic mammary glands
Well developed clavicles (collarbones)
Reduced olfactory sense & increased vision

24. Key Steps in Primate Evolution
Development of Opposable Thumb & Grasping Hand

25. Frees hands for manipulation &carrying Loss of opposable toe
2) Posture/Bipedalism
4 legged 2 legged
Increases sight range
Frees hands for manipulation &carrying
Loss of opposable toe
Loss of tail
Change in pelvic girdle
Shift in foramen magnum
Price we pay for bipedalism is
back pains and hemorrhoids

26. Loss of opposable toe
Shift for more stability

27. Shift in foramen magnum Dog Chimp (opening for spinal chord)
Quadrupeds have it in the
back of the skull.
Bipeds have it underneath.
Human

28. 3) Skull shape changes Prosimians (e.g. lemurs) Simians
Face shortens & Brain case enlarges
Prosimians
(e.g. lemurs)
Simians
(e.g. monkeys)

29. Shape of Jaw Changes

30. 4) Brain Size Increases

31. Primate Brains
Human Chimpanzee Monkey

32. Humans s

33. Humans s
Simians
Prosimians

34. 5) Increase in
Body
Size

35. 6) Reproduction
As body size increases
Embryo & offspring development time
Parental Care increases
Transfer of Learning from parents

36. 7) Social Behavior increases in complexity, with increased co-operation and communication
Solitary
Small family groups
Tribes
Nations

37. Expresions

38. Our view before Ardi

39. One common scheme

40. Here is a reconstruction of Ardi

41. For comparison look at these
Ardi

42. Ardi’s hands

43. Ardi’s feet

44. Can’t tell from the picture
Look at her feet. What does their structure suggest? Is there an opposable toe?
Yes No
Can’t tell from the picture 21

45. Look at Ardi’s pelvic girdle

46. Chimpanzee Modern Human Ardi

47. “These are very odd creatures,” says paleoanthropologist Allan Walker of Pennsylvania State University.
Tim White says, “If you want to find something that moved like these things, you’d have to go the bar in Star Wars.”

48. What did Ardi eat?
H. sapiens
Ardi
Chimp
Ardi’s teeth are rather general and she was probably ate a variety of food. Notice that her canines are less pronounced than chimps which use them for fighting. This has been interpreted to mean that she was less aggressive.

49. Where would you place Ardi in this sequence?B0 C) D) E) F_ G) H) I) J)
Here’s
Ardi 1

50. (A) Pan troglodytes, chimpanzee, modern
(B) Australopithecus africanus, STS 5, 2.6 My
(C) Australopithecus africanus, STS 71, 2.5 My
(D) Homo habilis, KNM-ER 1813, 1.9 My
(E) Homo habilis, OH24, 1.8 My
(F) Homo rudolfensis, KNM-ER 1470, 1.8 My
(G) Homo erectus, Dmanisi cranium D2700, 1.75 My
(H) Homo ergaster (early H. erectus), KNM-ER 3733, 1.75 My
(I) Homo heidelbergensis, "Rhodesia man," 300, ,000 y
(J) Homo sapiens neanderthalensis, La Ferrassie 1, 70,000 y
(K) Homo sapiens neanderthalensis, La Chappelle-aux-Saints, 60,000 y
(L) Homo sapiens neanderthalensis, Le Moustier, 45,000 y
(M) Homo sapiens sapiens, Cro-Magnon I, 30,000 y
(N) Homo sapiens sapiens, modern

51. The anthropologists concluded that Ardi lived in a woodland, climbing hackberry, fig, & palm trees coexisting with monkeys, kudu antelopes, and peacocks. Doves and parrots flew overhead.

52. “Multiple lines of evidence now suggest that they were beginning to leave the trees before they left the forest,” said Stanley Ambrose of the University of Illinois.

53. Timeline of Hominid Evolution

55. Body weights of different hominids
Body weights of different hominids. Predict the body weight of Ardi assuming she fits into the overall trend. Remember she is dated at 4.4 million years ago.
4.0 1

56. Based in these data, what would you predict the brain size of Ardi to be given that she was dated at 4.4. million years?
4.0 fr 1

57. Primate Brains Human Chimpanzee Monkey
Ardi had a brain the size of a chimpanzee
Human Chimpanzee Monkey

58. Summary
From the 11 papers in Science October 2, 2009
The skeleton nicknamed “Ardi” is from a female who lived in a woodland, stood about 120 cm. tall and weighed about 50 kg. She was thus about as big as a chimpanzee and had a brain size to match.
She did not knuckle-walk or swing through the trees like living apes. Instead she walked upright, planting her feet flat on the ground, perhaps eating nuts, insects, ad small mammals in the woods.
(There is no evidence that she used fire or communicated any more effectively than chimpanzees.)

59. * * Ardi Common ancestor
Rather than humans evolving from an ancient chimp-like creature, the new find provides evidence that chimps and humans evolved from some long-ago common ancestor—but each evolved and changed separately along the way.
"This is not that common ancestor, but it's the closest we have ever been able to come," said Tim White, director of the Human Evolution Research Center at the University of California, Berkeley.
Chimps
Humans
Ardi *
Common
ancestor *

60. Now, it is December again and Tim White and his team are back in Ethiopia, picking among the stones and rocks.
White stops to take a snapshot of the moon rising over Yardi Lake.
The landscape has changed over time, but one thing is constant

61. “Hominids have been right here looking
at the moon rising over the water for millions of years.”