1. Human Evolution

2. Human Evolution
I. What are humans related to?

3. Human Evolution
I. What are humans related to?
- Morphologically similar to apes

4. Human Evolution
I. What are humans related to?
- Morphologically similar to apes
- hands, binocular vision (Primates)
No tail

5. Human Evolution
I. What are humans related to? Apes

6. Human Evolution
I. What are humans related to? Apes
II. How do we differ?

7. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Behaviorally (walk erect)

8. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Behaviorally (walk erect)
- Behaviorally (intelligence and learning)

9. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Behaviorally (walk erect)
- Behaviorally (intelligence and learning)
- Morphologically, humans have:
- larger head/body ratio

10. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Behaviorally (walk erect)
- Behaviorally (intelligence and learning)
- Morphologically, humans have:
- larger head/body ratio
- smaller jaw/head ratio

11. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Behaviorally (walk erect)
- Behaviorally (intelligence and learning)
- Morphologically, humans have:
- larger head/body ratio
- smaller jaw/head ratio
- shorter arms/body ratio

12. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Behaviorally (walk erect)
- Behaviorally (intelligence and learning)
- Morphologically, humans have:
- larger head/body ratio
- smaller jaw/head ratio
- shorter arms/body ratio
- less hair

13. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Morphologically
Human Chimp Gorilla Orangutan Gibbon

14. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Genetically: Big Surprize!
Human Chimp Gorilla Orangutan Gibbon

15. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
- Genetically: Big Surprize!
Human Chimp Gorilla Orangutan Gibbon
< 1% difference in gene sequence

16. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
III. Resolution?
Can this 1% difference account for the dramatic behavioral and morphological differences we see?
Yes, some genes have big effects. These are regulatory genes, acting during development. They influence the expression of lots of other genes…

17. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
III. Resolution?
Can this 1% difference account for the dramatic behavioral and morphological differences we see?
Yes, some genes have big effects. These are regulatory genes, acting during development. They influence the expression of lots of other genes…
- Can we test this hypothesis? Do the differences correlate with developmental effects?

18. Yes. All differences correlate with developmental differences between juvenile primates and adults…
Juveniles Adults
Larger Head/body ratio smaller
Smaller jaw/head ratio larger
Shorter limb/body ratio longer
Less hair more hair
Better learning poorer learning

19. Yes. All differences correlate with developmental differences between juvenile primates and adults…
Juveniles Adults
Larger Head/body ratio smaller
Smaller jaw/head ratio larger
Shorter limb/body ratio longer
Less hair more hair
Better learning poorer learning
Human-like Ape-like

20. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
III. Resolution?
Can this 1% difference account for the dramatic behavioral and morphological differences we see?
Yes, if the small change is in developmental genes, they can have BIG effects…humans might be a type of ape that didn’t grow up…
The ways we differ supports this hypothesis…

21. Yes, if the small change is in developmental genes, they can have BIG effects…humans might be a type of ape that didn’t grow up…
Small changes in development, especially if they occur early in development, can result in big effects.
Human
Chimp
Primate developmental trajectory

22. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
III. Resolution?
IV. Are there common ancestors?

23. Molecular clock analyses

24. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
III. Resolution?
IV. Are there common ancestors?
Yes. Just where evolution predicts they should be (After other monkeys and apes, before humans and existing apes).

25. Science, Nov 19, 2004 12-13 mya – oldest ape
Pierolapithecus catalaunicus
12-13 mya – oldest ape

27. V. Are there common ancestors?
- Fossil and genetic analysis independently predicted a common ancestor between humans and chimps lived 5-8 million years ago.
Chimpanzee
Human
Homo sapiens

28. V. Are there common ancestors?
- Fossil and genetic analysis independently predicted a common ancestor between humans and chimps lived 5-8 million years ago.
Chimpanzee
Human
Homo sapiens
Sahelanthropus tchadensis – discovered in Chad in Dates to 6-7 mya. Only a skull. Is it on the human line? Is it bipedal? Probably not (foramen magnum). Primitive traits, as a common ancestor might have.

29. Human Evolution
I. What are humans related to? Apes
II. How do we differ?
III. Resolution?
IV. Are there common ancestors?
V. Are there intermediate links to modern humans?

30. V. Are there intermediate links to modern humans?
- yes, and in a nearly continuous sequence….
Chimpanzee
Australopithecus afarensis
Australopithecus africanus
Homo habilis
Human
Homo sapiens
Homo erectus

31. V. Are there intermediate links to modern humans?
- with a divergence of two types of hominids around 2 mya

32. V. Are there intermediate links to modern humans?
- with a divergence of two types of hominids around 2 mya

33. V. Are there intermediate links to modern humans?
- with a divergence of two types of hominids around 2 mya
“slender” species

34. V. Are there intermediate links to modern humans?
- with a divergence of two types of hominids around 2 mya
“slender” species
“robust” species

35. V. Are there intermediate links to modern humans?
- with a divergence of two types of hominids around 2 mya
Primitive species, with their bipedality disputed. Are they on the human line? The chimp line? Ancestral to both? Can’t tell – they are so INTERMEDIATE….

37. Morphological cladogram