Human Evolution

BIO 1114

Oklahoma City Community College

Dennis Anderson

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Animal Connection

• Humans share many traits with animals

• We are most similar to apes– Same 206 bones

– All but 3 of 650 muscles the same

– DNA is 98% the same

– Same blood typesAlbino Gorilla

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Why are we so similar to apes?

• Modern apes and modern man share a common ancestor who lived about 7 million years ago

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Sequence of Human Evolution

• Hundreds of fossils have been found

• Some of the major fossils will be discussed in this presentation

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Australopithecus afarensis

• 3.5 million years ago• Nicknamed Lucy• Walked upright• Small brain• Skeleton human like

– Feet– Pelvis– Upright stance

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Comparative Anatomy

• Gorilla pelvis adapted for knuckle walking• Human pelvis adapted for upright walking• Lucy’s pelvis very similar to human pelvis

Lucy

Human

Gorilla

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Knuckle Walking

• Requires an elongated pelvis and long arms

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

ape.

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Fossilized Footprints

• Footprints left when a a pair of Australopithecines walked in the ash of a recently erupted volcano

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Skull Anatomy

• Thick brow ridges like a chimpanzee• Cranial capacity 400 cc. Chimp 350 cc.• Teeth similar to human teeth

Chimp

Lucy

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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

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Australopithecus africanus

• 2.8 million years ago• Cranial capacity 460 cc

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Homo habilis

• Cranial capacity 630 cc• Flatter face than

Australopithecines• Used tools

– Nicknamed handy man

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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

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Homo erectus

• Skeleton very similar to modern man

• Used fire• Traveled

– Fossils found in Africa, Europe, China, Indonesia

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Homo neanderthalensis

• 200,000 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

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Homo sapiens

• 200,000 years ago to present– Photo is a skull 35,000

years old

• 1400 cc cranial capacity

• Vertical forehead• Pronounced chin

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Modern Homo sapiens

• Small front teeth• Small brow ridges• Rounded cranium

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Sequence of Human EvolutionOne of several possibilities

Common ancestor

Homo sapiens

Modern apes

Australopithecus afarensis

Australopithecus africanus

Homo habilis

Homo erectus

Homo neanderthalensis

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Evolution of Skull

• Cranial capacity increases for a larger brain• Face become flatter• Brow ridges become smaller• Forehead becomes higher• Chin develops

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Sahelanthropus tchadensis

• 6 to 7 million years ago• Flat face like Homo• Cranial capacity about the

same as a chimp• Walked upright

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The End