1. How Human Evolved Chapter 21
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2. Evolutionary Path to Apes First Hominid Origins of Bipedalism
Outline
Evolutionary Path to Apes
First Hominid
Origins of Bipedalism
Evolutionary Tree of Hominids
Lumpers
Splitters
Out of Africa
Homo erectus
Homo sapiens
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3. Evolutionary Path to Apes
Story of human evolution begins around 65 mya with explosive radiation of a group of small, aboreal mammals (Archonta).
Insectivorous nocturnal mammals.
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4. Evolutionary Path to Apes
Earliest Primates
Two distinct features that allowed them to succeed in aboreal environment:
Grasping fingers and toes
Binocular vision
Evolution of Prosimians
Earliest primates split into prosimians and anthropoids about 40 mya.
“Before Monkeys”
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5. Evolutionary Path to Apes
Origin of Anthropoids
Higher primates - Includes apes, monkeys, and humans.
One of most contentious issues in primate biology is identity of first anthropoid.
Direct Descendents:
New World Monkeys
Old World Monkeys
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6. Hominoids (apes and human) evolved from anthropoid ancestors.
How Apes Evolved
Hominoids (apes and human) evolved from anthropoid ancestors.
First Hominoid
Current attention is centered around a Miocene ape Proconsul which has many characteristics of Old World Monkeys, but lacks tail and has apelike hands, feet, and pelvis.
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7. Which Ape Is Our Closest Relative Asian apes evolved first.
How Apes Evolved
Which Ape Is Our Closest Relative
Asian apes evolved first.
Gibbons 15 mya - Orangutans 10 mya
African apes evolved 6-10 mya.
Closest living relative to humans.
Chimpanzees and humans share 98.4% of nuclear DNA.
Gorilla DNA differs from human DNA by about 2.3%.
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8. Comparing Apes to Hominoids
How Apes Evolved
Comparing Apes to Hominoids
Common ancestor of apes and hominids is thought to have been aboreal climber.
Hominids became bipedal.
Apes evolved knuckle-walking.
Multiple anatomy differences related to bipedal locomotion.
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9. Comparison of Ape and Hominid Skeletons
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10. Evolutionary Tree With Many Branches
Two major groups of hominids:
Homo
Australopithecus
Older
Smaller-brained
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11. Evolutionary Tree With Many Branches
Australopithecus - Bipedal
africanus
robustus
boisei
afarensis
Lucy
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12. Reason why bipedalism evolved is still controversial.
Origins of Bipedalism
Bipedalism seems to have evolved as our ancestors left dense forests for grasslands and open woodlands.
Reason why bipedalism evolved is still controversial.
Preceded large brains.
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13. Primate Evolutionary Tree
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14. Beginning of Hominid Evolution
Differing view of Hominid Tree
Lumpers
Focus on commonalities between fossils.
Splittters
Focus on differences between fossils.
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15. Lumper’s Approach to Homind Tree
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16. Splitter’s Approach to Hominid Tree
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17. Out Of Africa
First humans evolved from australopithecine ancestors about 2 million years ago.
Homo habilis
Homo rudolfensis
Homo ergaster
Still active debate whether Homo should be lumped into habilis, or split into three species.
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18. Homo erectus
Homo erectus was larger than H. habilis, had a larger brain, and walked erect. Skull had prominent brow ridges and a rounder jaw. Came out of Africa.
Java Man
Long Straight legs
Very Large brain
Bones 500,000 years old
Peking Man
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19. Last Stage of Hominid Evolution
Modern human first appeared in Africa about 600,000 years ago.
Three species of modern humans:
H. heidelbergensis
H. neanderthalensis
H. sapiens
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20. Out of Africa - Twice
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21. H. sapiens is the only surviving hominid.
Homo sapiens
H. sapiens is the only surviving hominid.
Best fossils are between 90,000 and 100,000 years old.
Cro-Magnons replaced Neanderthals about 40,000 years ago.
Humans of modern appearance eventually spread across Siberia to North America about 13,000 years ago.
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies

22. Evolutionary Path to Apes First Hominid Origins of Bipedalism
Review
Evolutionary Path to Apes
First Hominid
Origins of Bipedalism
Evolutionary Tree of Hominids
Lumpers
Splitters
Out of Africa
Homo erectus
Homo sapiens
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies

23. Copyright © McGraw-Hill Companies
Permission required for reproduction or display
Johnson - The Living World: 3rd Ed. - All Rights Reserved - McGraw Hill Companies