26.3 Human Evolution

Classification26.3

Homo sapiens sapiensKingdom Animalia

Phylum Chordata

Class Mammalia

Order Primates

Family Hominidae

Genus Homo

Species Sapiens

Subspecies Sapiens

Classification Humans are

primates Shared most

recent ancestor with chimpanzees ~6 mya

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What is a Primate? Mammals with:

Long fingers and toes with nails instead of claws

Flexible joints and limbs Binocular vision Well-developed cerebrum

Most adaptations for arboreal (tree-dwelling) life

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Long Fingers and Toes Allows firm

grip Claws

became nails to allow advanced grips

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Opposable Thumbs Thumbs that can

move against the other digits, Allows power

grip and precision grip

Most primates have these

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Flexible Joints Limbs can

rotate in broad circles around a strong shoulder joint

Strong clavicle (collar bone)

Well suited for climbing

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Binocular Vision Ability to

combine visual images from both eyes

Provides depth perception and a three-dimensional view of the world

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Large Cerebrum “Thinking” part of

the brain is large and intricate

Enables Complex

behaviors Critical thinking Reasoning

Many primates create elaborate social systems

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Human Evolution

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Humans are unique because of Bipedalism Large brains Advanced tool

use Language and

advanced culture

Bipedalism26.3

Walking on two legs Many skeletal changes

Pelvis, hips, knees, back, etc. Main advantage: tool use

Bipedalism

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Brain Size Increased

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Jaws and Teeth got Smaller

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Shift away from plant material in diet

Ancient Hominines

Australopithecus afarensis

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“Lucy” is one of the most famous human ancestor skeletons

Lived 4-1.5 mya Bipedal apes but

still very apelike Diet rich in fruit

Good climber Spent significant

time in trees

Ancient Hominines

Homo habilis

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Means “handy man”

Significant tool crafting and use

Speech possible

Ancient Hominines

Homo erectus

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1.9 and 0.3 mya. Extremely

successful and widespread

Larger brain and flatter face than Homo habilis

Much taller than previous hominids

First hominid known to use fire

Ancient Hominines

Homo erectus

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Ancient Hominines

Homo neanderthalensis

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200,000 years ago Massive brow

ridges with protruding nose, jaws, and teeth

Heavily muscled Culturally

advanced Manufactured

variety of tools Still traces of

Neanderthal DNA in humans today

Ancient Hominines

Homo sapiens

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~200,000 years ago

Cro Magnon is name for early humans

Advanced tools, communication, and culture

Entered Europe ~100,000 years ago Interbred with

Neanderthals Only hominine for

past 24,000 years

26.3