Download Life`s Origin and Evolution, Part II Archaean Eon 3.8

Life’s Origin
and Evolution,
Part II
Hadean Eon (i.e., Hell on Earth)
4.5 - 3.8 Billion Years Ago
Archaean Eon
3.8 - 2.5 Billion Years Ago
Life in the Universe - Astrobiology
Dr. R. L. Hudson (Fall, 2015)
Endogenous
Simple … to … Complex
H2, He,
CH4, NH3,
H2O, CO2, N2
Molecules
Type of Life: prokaryotic (bacteria)
The
Miller-Urey
Experiment
(1953)
Can make
amino acids
and more
Energy
Credit: AccessExcellence.org
Exogenous
Meteorites
And
Comets
Evolutionary Example:
Earth’s Atmosphere
H2, He, CH4, NH3, H2O, CO2, N2
CH4, NH3, H2O, CO2, N2
CO2, N2
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Stromatolites (again)
Rocks Change:
CO2 falls and O2 rises
Banded iron
formations in
rocks
http://www.ga.gov.au/education/minerals/ironform.html
Sunlight + CO2  O2
Photochemistry in
the Upper Atmosphere
O2  O + O
O + O2  O3
Ozone Shield
(6 - 30 miles up)
Fully oxidized rocks
~ 2.5 billion years ago
Earth Forms
~ 4.5 billion years ago
Prokaryotes
~ 3.5 billion years ago
Eukaryotes
~ 2 billion years ago
Eukaryotic Fossils
~ 2 billion years ago
Darwin’s gap
~ 0.5 billion years ago
land animals
hard shells
http://evolution.berkeley.edu/
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The Cambrian Explosion
Cambrian
Explosion
~ 545 million
years ago
The Cambrian Explosion
Charles Doolittle Walcott
(1850 – 1927)
Smithsonian
Institution
Secretary
For More Information
Charles Doolittle Walcott
(1850 – 1927)
Dr. Stephen Jay Gould
(1941 – 2002)
The Cambrian Explosion
The Cambrian Explosion
Charles Doolittle Walcott
(1850 – 1927)
Charles Doolittle Walcott
(1850 – 1927)
5 miles south
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Astrobiology Lesson
Astrobiology Lesson
Halophiles and methanogens - http://scitechdaily.com/researchers-may-be-able-to-sequence-genomes-of-any-microbes/
A Problem
Meteor Crater (Arizona)
~ 50,000 years ago
~ 1 mile across
Tunguska Event
Comet Shoemaker-Levy 9
June 30, 1908 in Siberia
800 miles2
80  106 trees
4 hours past St. Petersburg
July 18, 1994
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Impact Craters
Mass Extinction
Dramatic, sharp rise in death of animal or plant
life (or both) in a short period of time.
Impacts!
The K-T Impact
~ 65 million years ago
Several identified over 550  106 years
See organism below, but not
above, a certain rock strata
Two Pieces of Evidence
Chicxulub Crater
Mexico
Iridium Layer
Shocked Quartz
~ 100 miles in diameter
~ 65 millions years old
(Not “Chicks-U-Love”)
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Impact Crater In Mexico
The Chelyabinsk Impact
February 15, 2013
http://www.newyorker.com/news/news-desk/a-meteor-in-the-russian-sky
The Chelyabinsk Impact
February 15, 2013
Future Extinctions?
Supernova events
Gamma-ray bursters
Stellar ejection of Earth
Impacts
Galactic oscillations
(30  106 years)
Massive Impacts Can Reset
the Evolutionary Stage
Dinosaurs – Goodbye
Mammals – Hello
Sources of Material
Most of the images used here are either original,
from our class’s textbook, or in the public
domain. Material has been credited in cases
where I knew the sources. I will be glad to add
any credits missed.
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