Schedule

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Schedule

• 1. Monday, April 6 Jen, Jeremy, Justin,
  Joe 15 minute talks
• 2. Wednesday, April 8 Hannah, Noel, Richard,
  Emily 15 minute talks
• 3. Monday, April 13 Travis, Cassy, Robert,
  Adric 15 minute talks
• 4. Wednesday, April 15 Nic, Rachel, Zhao 15
  minute talks
• 5. Monday, April 20 WORK ON PAPERS
• 6. Wednesday, April 22 TURN IN FINAL
  PAPERS 6pm
• . Friday, April 24 Planets Party at Chez 401
  5th Street
• . Wednesday, April 29 three referee reports
  due 6pm (your final exam)

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The Votes Are In 2009
YES NO Life in Solar System? 10
3 Life in Universe? 13 0 Intelligent
Life in Solar System? 0 13 Intelligent
Life in Universe? 10 3
3
The Votes Are In 2006
YES NO Life in Solar System? 7
7 Life in Universe? 14 1 Intelligent
Life in Solar System? 1 14 Intelligent
Life in Universe? 12 3
4
The Votes Are In 2003
YES NO Life in Solar System? 10
1 Life in Universe? 11 0 Intelligent
Life in Solar System? 1 10 Intelligent
Life in Universe? 11 0
5
The Votes Are In Totals
YES NO Life in Solar System? 27
11 Life in Universe? 38 1 Intelligent
Life in Solar System? 2 37 Intelligent
Life in Universe? 33 6
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Cyanobacteria
1. developed RNA, DNA, proteins 2. invented
photosynthesis 6 CO2 6 H2O
sunlight ? C6H12O6 6 O2
energy 3. created O2, poisoned competitors
note that prokaryotes show evidence of
Earths oxidation some die in
O2, some dont care about O2, some must have O2
effectively all eukaryotes need
O2 4. learned to use the O2
aerobic are 18X more efficient energy production
than anaerobic chloroplasts
photosynthesizing cyanobacteria
mitochondria O2 breathing cyanobacteria that
invaded eukaryotes
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Cyanobacteria Portraits
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Cyanobacteria Youve Seen Them
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Stromatolites
stromatolites are structures left by cyano
colonies (claims) date back to 3.5
Gyr cells live in mats/reefs, sediments CaCO3
trapped cyanobacteria move up O2
producers on top, O2 avoiders on bottom
fossils show the life processes of
cyanobacteria only seen now in hypersaline
environments
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Classifying Life Forms (old way)
Kingdom Phylum Class Order Family
Genus Species Keep Pot Close,
On Fridays Get Stoned 5 Kingdoms
Monera bacteria, including cyanobacteria
Protista amoebae, paramecia, euglenae
Fungi mushrooms, molds, mildews, yeasts
Plant mosses, ferns, flowering plants, bushes,
trees Animal insects, jellyfish, crabs,
fish, birds, lions, tigers, and bears
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Molecular Phylogeny (new way)
TECHNIQUE a. align homologous gene sequences
from different organisms b. count number of
differences, a measure of evolutionary
distance c. construct phylogenetic trees, i.e.
evolution maps
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Tree of Life (today)
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Molecular Phylogeny
TECHNIQUE a. align homologous gene sequences
from different organisms b. count number of
differences, a measure of evolutionary
distance c. construct phylogenetic trees, i.e.
evolution maps RESULTS 3 main related groups
? Archaea, Bacteria, Eucarya origin of life is
found at the tree root, and is on the Bacterial
line of descent because Archaea and Eucarya
are related to the exclusion of Bacteria tend
to find thermophiles near tree root (but
debated) major organelles (mitochondria,
chloroplasts) are of Bacterial ancestry most
biodiversity is found in microbes (the small
stuff really matters)
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Diversity of Life
Total number of eukaryote species cataloged
1,600,000 World Conservation Union
www.currentresults.com/Environment-Facts/Plants-An
imals/number-species.php Invertebrate
Animals 1,200,000 insects 950,000 Plants
300,000 flowering (angiosperms) 260,0
00 Vertebrate Animals 60,000 fish
29,300 birds 9,956 reptiles
8,240 amphibians 6,199 mammals
5,416 Lichens, Mushrooms, Brown Algae
30,000 Identifying a species before its extinct
priceless biologists have
identified 16
Environmental Requirements for Life
1. solid surface CHON found in abundance 2.
atmosphere and/or ocean mixing,
solubility protection from photons gamma,
x-ray, UV protection from particles solar wind,
cosmic rays protection from impacts time 3.
stability radiation orbital
dynamics temperature greenhouse
effect escape Snowball Earth living
planet 4. energy source(s)
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Energy Sources in Solar System
nuclear fusion hydrogen ? helium solar
radiation greenhouse effect differentiation grav
itational settling radioactive decay volcanism ti
dal heating friction from direct
tides stressing via orbital resonances charged
particles from Sun or planet charged particle
imbalance lightning ohmic heating Io deep in
Jupiter magnetosphere lead to
metabolism photosynthesis, respiration, eating
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Solar System Locations for Life
1 star Sun 4 terrestrial planets Mercury,
Venus, Earth, Mars 2 gas giant
planets Jupiter, Saturn 2 ice giant
planets Uranus, Neptune 7 large moons Moon,
Io, Europa, Ganymede, Callisto,
Titan, Triton small moons, asteroids, Phobos,
Ceres, Amalthea, comets, KBOs, dust Rhea,
Enceladus, Titania, Proteus, Pluto, Charon
WHICH ARE THE BEST OPTIONS?
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Solar System Locations for Life
1 star Sun 4 terrestrial planets Mercury,
Venus, Earth, Mars 2 gas giant
planets Jupiter, Saturn 2 ice giant
planets Uranus, Neptune 7 large moons Moon,
Io, Europa, Ganymede, Callisto,
Titan, Triton small moons, asteroids, Phobos,
Ceres, Amalthea, comets, KBOs, dust Rhea,
Enceladus, Titania, Proteus, Pluto, Charon
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Case for Life As We Know It
no shortage of locations with varying
environments plenty of energy from stars,
impacts, weather raw materials, CHON, are
ubiquitous evidence of chemical evolution found
in meteorites and GMCs DNA made of a few basic
molecules (aas, sugars, phosphates) significant
evidence of evolutionary adaptability time se
ries of unlikely accidents required? the
universe can be an unforgiving place no
experiment has produced a living organism (but,
virus made) no evidence! but, it is early
in the game
1 2 3 5 4
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The Drake Equation
N R fg fp ne fl fi fc
L N civilizations with detectable
electromagnetic emissions R rate of star
formation (stars/year) fg fraction of stars that
are suitable for development of life fp fraction
of stars with planetary systems ne of
worlds/system with environment suitable for
life fl fraction of planets on which life
develops fi fraction of life-bearing planets on
which intelligent life arises fc fraction of
intelligent civilizations revealing
existence L length of time civilizations release
detectable signals (years)
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Solar System Explorers 2009-8
Give one logical scientific experiment YOU might
carry out to constrain a factor in the Drake
Equation. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12
. 13. 14. 15. 16. 17. 18. 19. 20.
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Solar System Inventory 2006
1 8 152 (as of 2006 JAN 17)
4 305,000a (as of 2005 DEC 15) 923 (as of
2006 JAN 17) 95,000b (as of 2005 DEC 15)
dust a with orbits b
periodic and numbered

• stars
• planets
• moons
• ring systems
• minor planets
• Kuiper Belt Objects
• comets
• and

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Solar System Inventory 2009
1 8 165 (as of 2009 JAN
11) 41 436,000a (as of 2008 DEC 12)
1,300 (as of 2009 JAN 11) 152,000b (as
of 2008 DEC 15) dust a with orbits b
periodic and numbered

• stars
• planets
• moons
• ring systems
• minor planets
• Kuiper Belt Objects
• comets
• and

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Solar Family
How are they different?
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The Seven Dwarfs
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Nice Earth
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Voyagers Farewell
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Solar System Explorers 2009-7
How would the environment be different on an
Earth-sized world 1 AU from Proxima Centauri? 1.
We would likely evolve to see primarily at
infrared wavelengths. 2. Many more sunspots would
lead to changing radiation levels. 3. Ambient
temperature outside atmosphere much colder. 4.
Primary energy source (star) is lower geothermal
might help. 5. Likely to have less massive
planets in solar system because formation disk
less massive. 6. Orbital period is longer, at
2.85 years. 7. Assuming ambient temperature, CO2
will freeze out. 8. Longer seasons if theres a
tilt. 9. Flaring would lead to more interesting
aurorae. 10. Planet composition would be
different --- disk temp different/Proxima has
higher metallicity than Sun. 11. Constellations
would be SLIGHTLY different. 12. Multiple suns in
the sky with Alpha Cen AB nearby. 13. Sol
magnitude would be 0.39. 14. Aberration of
starlight because Proxima moving slower. 15.
Stellar activity cycle 442 days instead of 11
years. 16. Disk of Proxima would be only 4 arcmin
in size. 17. Possibly outside of proxiopause so
cosmic rays a real problem. 18. Flux from Proxima
is 0.0017 of flux from Sun. 19. If more ice, then
higher albedo. 20. More X-rays leads to more
sputtering and more radiation darkening.
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