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

Dr. Stanley Miller ( )

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:

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 the Tarsiers

Primates (order) ProsimiansAnthropoids Old world monkeysNew world monkeyshominoids 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 years old Approx. 60 pounds Approx. 3 ft tall Discovered by Dr. 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

male Approximately 12 years old Lived approximately 1.6 million years ago Homo erectus (stood approximately 5 ft tall) Turkana Boy Found 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 sapien Cro-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.