1. Biology, 9th ed, Sylvia Mader
Chapter 32
Chapter 32
Human Evolution
Human Evolution

2. Evolution of Early Hominids Evolution of Later Hominids
Outline
Evolution of Primates
Mobile Limbs
Binocular Vision
Evolution of Early Hominids
Evolution of Later Hominids
Evolution of Early Homo
Modern Humans
Human Variation

3. The evolution of primates is characterized by trends towards:
Mobile limbs
Grasping hands
A flattened face
Binocular vision
A large, complex brain, and
A reduced reproductive rate

4. Primate Diversity

5. Mobile Limbs Hands and feet
Most primates have flat nails
Sensitive pads on the undersides of fingers and toes
Many also have both an opposable big toe and thumb
Mobile limbs and clawless opposable digits allow primates to freely grasp and release tree limbs

6. Evolution of Primate Hand

7. Binocular Vision
Stereoscopic vision
Depth perception
Allows primates to make accurate judgments about distance and position of adjoining tree limbs

8. Binocular Vision

9. Primate Characteristics
Opposable thumb
Nails instead of claws
Single births
Binocular vision
Expanded, complex brain
Emphasis on learned behavior

10. Surviving anthropoids are classified into three superfamilies
Evolution of Primates
Prosimians were the first type of primate to diverge from the human line
Surviving anthropoids are classified into three superfamilies
New World monkeys
Old World monkeys
Hominoids

11. Evolution of primates

12. Proconsul is believed ancestral to hominids
Evolution of Hominids
Proconsul is believed ancestral to hominids
Phylogenetic tree indicates humans are most closely related to African apes
Genetic changes used as a molecular clock to measure relatedness of different groups
Last common ancestor appears to have lived about 7 mya

13. Monkey Skeleton Compared to Proconsul Skeleton

14. Skeletal differences between humans and apes largely because:
Hominids
Hominid fossils:
Must have an anatomy suitable for standing erect and walking on two feet
Bipedalism
Skeletal differences between humans and apes largely because:
Humans are bipedal, while
Apes are quadrupedal

15. Adaptations for Standing

16. Australopithecines Australopithecines:
Evolved and diversified in Africa 4 mya
Possibly a direct ancestor of humans
Southern Africa
Australopithecus africanus
Eastern Africa
Australopithecus afarensis

17. Human Evolution

18. Australopithecus afarensis

19. Evolution of Early Homo
Homo habilis
Dated between 20 an 19 mya
May be ancestral to modern humans
Skulls suggest portions of the brain associated with speech were enlarged
Ability to speak may have led to hunting cooperatively and the advent of culture

20. Homo erectus and similar fossils
Found in Africa, Asia, and Europe
Dated between 19 and 03 mya
Larger brain and flatter face than Homo habilis
Much taller than previous hominids
Thought to have first appeared in Africa and then migrated into Asia and Europe
First hominid to use fire

21. Homo ergaster

22. Evolution of Modern Humans
Most researchers believe Homo sapiens evolved from Homo erectus
Multiregional Continuity Hypothesis
Similar evolution occurred in many different places
Out-of-Africa Hypothesis
H. sapiens evolved from H. erectus only in Africa, and thereafter migrated to Europe

23. Evolution of Modern Humans

24. Neanderthals
Neanderthal (H. neanderthalensis) skeletons were first discovered in Germany’s Neander Valley
Skeletons date back 200,000 years
Massive brow ridges with protruding nose, jaws, and teeth
Heavily muscled
Culturally advanced
Manufactured variety of tools

25. Neandertals

26. Oldest fossils to be designated H. sapiens
Cro-Magnons
Oldest fossils to be designated H. sapiens
Modern humans who entered Asia and Europe from Africa 100,000 years ago
Made advanced stone tools
Accomplished hunters
Hunted cooperatively
First to have language

27. Cro-Magnons

28. Comparative study of mitochondrial DNA
Human Variation
Hypothesized that human variations evolved as adaptations to local environmental conditions
Bergmann’s Rule - Animals in colder regions of their range have a bulkier body build
Allen’s Rule - Animals in colder regions of their range have shorter limbs, digits, and ears
Comparative study of mitochondrial DNA
Suggests human populations have a common ancestor no more than a million years ago

29. Ethnic Groups

30. Evolution of Early Hominids Evolution of Later Hominids
Review
Evolution of Primates
Mobile Limbs
Binocular Vision
Evolution of Early Hominids
Evolution of Later Hominids
Evolution of Early Homo
Modern Humans
Human Variation

31. Biology, 9th ed, Sylvia Mader
Chapter 32
Ending Slide Chapter 32
Human Evolution
Human Evolution