1. Human Evolution

2. The Evolution of Humans

3. Theory of Evolution
Science has overwhelming evidence that all life is constantly evolving

4. Natural Selection One mechanism of evolution
Main concepts of natural selection
Overproduction of offspring
Inherited variation in offspring
Competition
Best adapted in a given environment survive and reproduce to increase their kind
They are naturally selected

5. Overproduction of Offspring
Elephants (very slow reproductive rate)
If all the offspring of one elephant pair survive and all their offspring survive then:
750 years = 19,000,000 elephants
1200 years = Enough elephants to cover the earth!
Beetles
A handful that weighs 10 mg each
82 weeks
61,000,000,000,000,000,000,000 ton
The weight of the earth!

6. The Evolution of Humans

7. Variation of Offspring
Offspring of the same parents are different from each other

8. Competition
Since more individuals are born than can survive for an extended period of time, they compete for resources
Food
Living space
Mates

9. Best adapted to a given environment are selected to survive
Brown bears
Adapted to survive in Oklahoma
Polar bears
Adapted to survive in Alaska

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. Sequence of Human Evolution
Hundreds of fossils have been found
Some of the major fossils will be discussed in this presentation

12. Australopithicus afarensis
3.5 million years ago
Nicknamed Lucy
Walked upright
Small brain
Skeleton human like
Feet
Pelvis
Upright stance

13. Comparative Anatomy Gorilla pelvis adapted for knuckle walking
Lucy
Gorilla
Human
Gorilla pelvis adapted for knuckle walking
Human pelvis adapted for upright walking
Lucy’s pelvis very similar to human pelvis

14. Knuckle Walking
Requires an elongated pelvis and long arms

15. Lucy’s pelvis allowed her to walk like a human instead of an ape.

16. Fossilized Footprints
Footprints left when a a pair of Australopithecines walked in the ash of a recently erupted volcano

17. Skull Anatomy Thick brow ridges like a chimpanzee
Lucy
Chimp
Thick brow ridges like a chimpanzee
Cranial capacity 400 cc. Chimp 350 cc.
Teeth similar to human teeth

18. Lucy: A Transitional Fossil
Transitional fossil shows characteristics of two kinds of animals
Represent the transition from one organism to another
Ape characteristics
Skull
Cranial capacity
Human characteristics
Walked upright
Feet
Pelvis

19. Australophithicus africanus
2.8 million years ago
Cranial capacity 460 cc

20. Homo habilis Cranial capacity 630 cc
Flatter face than Australopithecines
Used tools
Nicknamed handy man

21. Homo erectus 1.8 million to 35,000 years ago 1,000 cc cranial capacity
Large brow ridges
Sloping forehead
More advanced tools than H. habilis

22. Homo erectus Skeleton very similar to modern man Used fire Traveled
Fossils found in Africa, Europe, China, Indonesia

23. Homo neanderthalensis
135,000 to 25,000 years ago
Cranial capacity up to 1750 cc
Larger than modern man
No chin
Sloping forehead
Buried dead with tools and flowers

24. The Evolution of Humans
The Cro-Magnons and the Neanderthals

25. Homo sapiens 200,000 years ago to present 1400 cc cranial capacity
Photo is a skull 100,000 years old
1400 cc cranial capacity
Vertical forehead
Pronounced chin

26. The Evolution of Humans
What about the Neanderthals?

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

28. Modern Homo sapiens Small front teeth Small brow ridges
Rounded cranium

29. Sequence of Human Evolution One of several possibilities
Homo neanderthalensis
Australopithicus afarensis
Australopithicus africanus
Homo erectus
Common ancestor
Homo habilis
Homo sapiens
Modern apes

30. Evolution of Skull Cranial capacity increases for a larger brain
Face become flatter
Brow ridges become smaller
Forehead becomes higher
Chin develops

31. Tools used to learn about our evolutionary past
Study of fossils
Comparing DNA
Comparing chromosomes
Comparing protein sequences

32. Paleontology Study of fossils
Allows us to see anatomical similarities between us and organisms that lived in the past
Allows us to see how our ancestors have changed over time

33. Comparing DNA Human DNA compared to: Chimpanzee 99% same
Gorilla 97.7% same
Orangutan 96.3% same
Another human 99.9% same

34. 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...

35. The Evolution of Humans