Transcript carbon dioxide

The Evolution of the
Atmosphere:
4.6 to 1 billion years ago
By
Ms. Holl
Introduction
THREE PARTS:
• PART I: Volcanoes
• PART II: Single-Celled Plants
• Part III: Multi-Celled Plants
Part I
Volcanoes
Part II
Multi-Celled Plants
Stromatolites
Formed by colonies
cyanobacteria.
At least 3.5 billion
years old.
Carbon is stored in
stromatolites.
Fact:
Chloroplasts are
actually cyanobacteria
living in plant cells!
0.5 to 3.5 billion years ago
Stromatolites,
colonies of
cyanobacteria,
are alive in
Australia today.
Shark Bay, Australia
2-3 billion years ago:
Little free oxygen
Commonly occur in sedimentary
rocks 2-3 billion years old.
Alternating dark bands
(containing FeO) and light bands
of chert (silica and Fe2O3).
Occur from the deposition of
alternately dissolved FeO &
chert.
“Bands” occur from fluctuating
densities of bacteria in an
ocean. When bacteria blossoms,
it creates oxygen and thus chert,
which falls to the ocean floor.
An oxygen depletion allows for
FeO.
Banded iron formation
History of Atmospheric Oxygen
The presence of FeS2 and UO2
set upper limits because oxygen
would have produced other
oxides from U and Fe
From Lunine 1999 based on Kastings (1991)
Red beds
Occur earlier than 2
billion years ago.
Form when iron is
weathered out of rock in
the presence of oxygen.
Part III
Multi-Celled Plants
Summary
• PART I: Volcanoes add carbon dioxide, ammonia,
methane, and water vapour to the atmosphere.
• PART II: Single-celled plants begin to photosynthesize
which decreases the amount of carbon dioxide and
increases the amount of oxygen in the atmosphere. The
oxygen reacts with ammonia from volcanoes to add
nitrogen to the atmosphere.
• PART III: Multi-celled plants evolved which adds even
more oxygen to the atmosphere. More nitrogen is added
as plants decay and are consumed by denitrifying
bacteria.
Review Questions
• Millions of years ago, the atmosphere
contained the following gases:
– Ammonia, carbon dioxide, methane, nitrogen,
oxygen and water vapor.
• Which of these gases has increased?
• Which of these gases has decreased?
Review Questions
• Does photosynthesis increase or decrease
the amount of oxygen in the atmosphere?
– WHY?
• Does photosynthesis increase or decrease
the amount of carbon dioxide in the
atmosphere?
– WHY?
Review Questions
• How did volcanoes change the atmosphere?
• How did single-celled plants change the
atmosphere?
• How do multi-celled plants change the
atmosphere?
To think about…
• How is the composition of the atmosphere
changing today?
Picture Sources
http://rainbow.ldeo.columbia.edu/courses/v1001/7.html
http://www.geol.umd.edu/~kaufman/ppt/chapter3/sld019.htm
http://www.uta.edu/geology/geol1425earth_system/images/gaia_chapter_1
1/ArcheanLandscape.jpg
http://www.uta.edu/geology/geol1425earth_system/1425chap11.html
http://www.geol.umd.edu/~kaufman/ppt/chapter3/sld019.htm
http://www.exhibits.lsa.umich.edu/Exhibits/Anthropology/Diaramas/Nat.Am.
/Copper/Copper.html
http://www.novaspace.com/LTD/TUCC/PIX/Atmo.jpeg
http://www2.jpl.nasa.gov/files/images/browse/p46022bc.gif
http://www.gsfc.nasa.gov/gsfc/earth/pictures/pinatubo/atmosphere%20after
.jpg
http://commons.wikimedia.org/wiki/Image:Air_composition_pie_chart.JPG
http://www.photolib.noaa.gov/sanctuary/images/big/sanc0001.jpg
Information Sources
• http://www.udayton.edu/~INSS/ThemeE
vol/EvolTimeline.HSM.ppt
• http://www.lpl.arizona.edu/undergrad/cla
sses/spring2006/Griffith_10213/LectureNotes/L36-Evolution-Life.ppt
• http://thurmanscience.tripod.com
• http://www.olduniverse.com/1,2.htm