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Human Evolution. www.okc.cc.ok.us/deanderson/index/human_evolution.ppt. The Evolution of Humans. Theory of Evolution. Science has overwhelming evidence that all life is constantly evolving. Natural Selection. One mechanism of evolution Main concepts of natural selection

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Human evolution
Human Evolution

www.okc.cc.ok.us/deanderson/index/human_evolution.ppt



Theory of evolution
Theory of Evolution

  • Science has overwhelming evidence that all life is constantly evolving


Natural selection
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


Overproduction of offspring
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!



Variation of offspring
Variation of Offspring

  • Offspring of the same parents are different from each other


Competition
Competition

  • Since more individuals are born than can survive for an extended period of time, they compete for resources

    • Food

    • Living space

    • Mates


Best adapted to a given environment are selected to survive
Best adapted to a given environment are selected to survive

  • Brown bears

    • Adapted to survive in Oklahoma

  • Polar bears

    • Adapted to survive in Alaska


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


Sequence of human evolution
Sequence of Human Evolution

  • Hundreds of fossils have been found

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


Australopithicus afarensis
Australopithicus afarensis

  • 3.5 million years ago

  • Nicknamed Lucy

  • Walked upright

  • Small brain

  • Skeleton human like

    • Feet

    • Pelvis

    • Upright stance


Comparative anatomy
Comparative Anatomy

Lucy

Gorilla

Human

  • Gorilla pelvis adapted for knuckle walking

  • Human pelvis adapted for upright walking

  • Lucy’s pelvis very similar to human pelvis


Knuckle walking
Knuckle Walking

  • Requires an elongated pelvis and long arms



Fossilized footprints
Fossilized Footprints an ape.

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


Skull anatomy

Lucy an ape.

Chimp

Skull Anatomy

  • Thick brow ridges like a chimpanzee

  • Cranial capacity 400 cc. Chimp 350 cc.

  • Teeth similar to human teeth


Lucy a transitional fossil
Lucy: A Transitional Fossil an ape.

  • 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


Australophithicus africanus
Australophithicus africanus an ape.

  • 2.8 million years ago

  • Cranial capacity 460 cc


Homo habilis
Homo habilis an ape.

  • Cranial capacity 630 cc

  • Flatter face than Australopithecines

  • Used tools

    • Nicknamed handy man


Homo erectus
Homo erectus an ape.

  • 1.8 million to 35,000 years ago

  • 1,000 cc cranial capacity

  • Large brow ridges

  • Sloping forehead

  • More advanced tools than H. habilis


Homo erectus1
Homo erectus an ape.

  • Skeleton very similar to modern man

  • Used fire

  • Traveled

    • Fossils found in Africa, Europe, China, Indonesia


Homo neanderthalensis
Homo neanderthalensis an ape.

  • 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


The Evolution of Humans an ape.

The Cro-Magnons and the Neanderthals


Homo sapiens
Homo sapiens an ape.

  • 200,000 years ago to present

    • Photo is a skull 100,000 years old

  • 1400 cc cranial capacity

  • Vertical forehead

  • Pronounced chin


The Evolution of Humans an ape.

  • What about the Neanderthals?


The Evolution of Humans an ape.

  • What about the Cro Magnons?


Modern homo sapiens
Modern an ape.Homo sapiens

  • Small front teeth

  • Small brow ridges

  • Rounded cranium


Sequence of human evolution one of several possibilities

Homo neanderthalensis an ape.

Australopithicus afarensis

Australopithicus africanus

Homo erectus

Homo habilis

Common ancestor

Modern apes

Sequence of Human EvolutionOne of several possibilities

Homo sapiens


Evolution of skull
Evolution of Skull an ape.

  • Cranial capacity increases for a larger brain

  • Face become flatter

  • Brow ridges become smaller

  • Forehead becomes higher

  • Chin develops


Tools used to learn about our evolutionary past
Tools used to learn about our evolutionary past an ape.

  • Study of fossils

  • Comparing DNA

  • Comparing chromosomes

  • Comparing protein sequences


Paleontology
Paleontology an ape.

  • 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


Comparing dna
Comparing DNA an ape.

  • Human DNA compared to:

    • Chimpanzee 99% same

    • Gorilla 97.7% same

    • Orangutan 96.3% same

    • Another human 99.9% same


The Evolution of Humans an ape.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...



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