EVOLUTION

Ch. 23

Evolution

Evolution Outline• Formation of the earth & chemical evolution

• Early beginnings of cells

• Critical events leading to evolution Evidence • Evidence supporting evolution

• Early Primate evolution

• Evolution of the Genus Australopithecines

• Evolution of the Genus Homo & modern humans

4.5 billion years ago the earth formed

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•Dr. Stanley Miller (1930-2007)

Miller’s Experiment showed:

• Organic molecules can be formed from components of Earth’s early atmosphere.

Collections of polymers.heterotrophs

autotrophs

Earth formed

Chemical Evolution began

First Eukaryotes emerged

First Prokaryotes emerged

4.5 billion years ago

4 billion years ago

3.5 billion years ago

1.2 billion years ago

Insects 40 million years ago trapped in amber

SUMMARY

Ocean

First species to invade the land came from the oceans were likely plants. Soon after the plants invaded, animals came ashore.

First animals were probably scropion-like.

Evolutionary changes

• Anatomical

• Functional

• Behavioral

How do these changes occur?

Charles Darwin: 1809-1882

1831-1836

1859

DARWIN’s TRAVELS

2 conflicting theories

Key components of evolutionary process

• Genetic variation

• Natural selection

• Survival of the Fittest

Evidence supporting natural selection

1. Fossil records

2. Homologous structures

3. Biochemical similarities

– DNA– Amino acids

98% similar

Humans

Chimpanzees

(DNA of fossils is also being studied)

4. Embryologic development

Sea urchin

Cockatiel

Mouse

Human

• 5. Biogeography

Super continent 240 million years ago

• 6. Experimental Evidence

Primate Evolution

Earliest primates included theTarsiers

Primates (order)

Prosimians Anthropoids

Old world monkeys hominoidsNew world monkeys

Great Apes

Lesser Apes

Hominids

Genus:Australopithecus

Genus: Homo

Consist of

Ruff lemur tarsier

Consist of:

Mandrill Spider Monkey

Australopithecus afarensis

Approx. 3.2 mya

“Lucy”

Approx. 25-30 years old

Approx. 60 pounds

Approx. 3 ft tall

Discovered byDr. Donald Johanson mid 70’s

Australopithecus afarensis

• Bipedal• Approximately 3 to 5.6 ft in height

• Over 1 million years ago Australopithecus disappeared.

Homo habilis“skillful man”

• Lived 1.8 million years ago

• Discovered 1960 in Tanzania by Dr. Mary Leakey

Brain is 50% larger than Australopithecus

Homo erectus“upright man”

• Lived 1.6 million years ago

• H. erectus moved from Africa to Europe and Asia

Used fire

maleApproximately 12 years oldLived approximately 1.6 million years ago

Homo erectus(stood approximately 5 ft tall)

Turkana BoyFound in 1984 in Kenya

Homo sapien“thinking man”

• Emerged approx. 300,000 years ago

• 2 subspecies– neaderthalensis– sapien

Skull of Homo sapien neanderthalensis

Lived in small clans and had elaborate burial rituals.

Homo sapien sapien

• Neaderthanls disappeared about 40,000 years ago

• About 300,000 years ago enter Homo sapien sapien

Skull of early Homo sapien sapien

Cro-Magnon Man

Homo sapien sapienCro-Magnon Man

Artistic with perhaps a well developed language

Excellent hunters

Lived in communities

Homo sapien sapien“modern man”

• Appeared approximately 10,000 years ago

• Very little change over the past 40,000 years

The End(or beginning !)

An artist’s interpretation of how “Lucy” may have looked.