EVOLUTION
Evolution
(material for extra credit questions)
Outline
• Approximate date of earth formation
• Theory of Chemical Evolution & evidence for chemical evolution
– Miller’s Experiment
• Timeline for emergence of first Cells
• 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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Earth formed
Chemical Evolution began
4.5 billion years ago
4 billion years ago
First Prokaryotes emerged
3.5 billion years ago
First Eukaryotes emerged
1.2 billion years ago
Miller’s Experiment showed:
• Organic molecules can be formed from
components of Earth’s early atmosphere.
heterotrophs
autotrophs
Collections of polymers.
Ocean
First species to come to land from our oceans were plants.
PLANT LIFE
• Plants provided O2
• Provided ozone layer
• Protection against UV
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 of fossils is also being studied)
– DNA
– Amino acids
Humans
98% similar
Chimpanzees
4. Embryologic development
Mouse
Human
Cockatiel
Sea urchin
• 5. Biogeography
Super continent 240 million years ago
• 6. Experimental Evidence
Primate Evolution
Earliest primates included the
Tarsiers
Ruff
lemur
tarsier
Consist of
Prosimians
Old world monkeys
Primates (order)
Anthropoids
New world monkeys
hominoids
Consist of:
Great Apes
Lesser Apes
Hominids
Genus:Australopithecus
Mandrill
Spider Monkey
Genus: Homo
Australopithecus afarensis
“Lucy”
Approx. 25-30 years old
Approx. 60 pounds
Approx. 3 ft tall
Discovered by
Dr. Donald Johanson mid 70’s
Approx. 3.2 mya
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
Homo erectus
(stood approximately 5 ft tall)
Turkana Boy
Found in 1984 in Kenya
male
Approximately 12 years old
Lived approximately 1.6 million years ago
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!