the Second Midterm
This exam covers the material from the April 29 -- May 24 Lectures
What to really know and what are the key concepts?
Galaxies and Supernova
- Different kinds of Galaxies: Spirals vs Ellipticals
- Formation of elements via fusion --> up to Iron
- Formation of elements beyond Iron; Neutron Capture
- R-process vs S-process
- Formation of Uranium
- Seeding the Galaxy with heavy elements
- Supernova are the Cosmic Womb and the means by which
the Universe is connected
Formation of the Earth:
- Chemically enriched dusty disk forms around the Sun
- Temperature Gradient in this disk means dense planets form
close to the sun and low density objects form far from the Sun
- Planets form via 4-step accretion process
- Left over debris craters the newly formed planetary surfaces
- How did the earth get its water?
- Jupiter and cometary bombardment
- Where did the moon come from? Significantly different density
than the Earth?
- Supercomputer tells us that a collision with a Mars sized object
with the molten proto-earth produced debris that coalesced to form
the moon -- pretty wild but seems to be the only way to account for
its anamolous density
Evolution of the Earth's Atmosphere
Formation of Life in the Oceans:
- Original Atmosphere of Hydrogen and Helium lost
- Secondary atmosphere composed mostly of CO2 and
- Earth is at the right distance from the sun to produce a
temperature conducive for the condensation of water vapor
- Condensation of the oceans and the dissolution of CO2
into the oceans
- What happened to the water on Mars and Venus?
- Most of the earth's atmosphere now in the oceans leaving behind
Nitrogen which is chemically inert and stays in the atmosphere.
- Trace amounts of methane and ammonia react with water and
energy to produce simple amino acids which rain down into the ocean.
Nine Steps: ( Know the timeline )
- Chemical synthesis of organic molecules --> monomers
- Concentration of monomers to facilitiate the formation of
- trial and error combination of polymers until DNA is discovered.
Microwave background --> uiverse is filled with photons at some
- Multiplying population for bacteria initially feeds off each
other through fermentation process
- Anerobic photosynthesis presents the first advantageous alternative
to cells getting energy through fermentation
- Chlorophyll evolves to more efficiently harness the energy from
UV photons --> this leads to areobic photosynthesis with O2
as a waste product
- O2 given off in the ocean no harmful to unprotected
DNA. Fortunately dissolved Iron in the ocean scavanges the O2
to make FeO2 which settles out to the ocean floor
- Gradually over 1 billion years or so prokaryotic cells evolve into
eukaryotic cells in which the DNA is in the cell nucleus. O2
is used as a catalyst for rapid cell division (mitosis) leading to
the formation of multi-cellular creaters.
- Eventaully all the FeO2 settles out and the O2
now can go into the earth's atmosphere which allows for the formation
of the ozone layer
Life On the Land:
- 700 million years ago species begin to migrate from the
Sea to the Land
- Land is an unstable ecosystem on long timescales
- Plate Tectonics --> volcanoes and earthquakes; continental
drift and disruption of migration patterns
- Climatological catastropher --> Big Ice Ages
- Mass Extinctions --> 2/3 of all species extinct. Affects both
ocean and land life.
- Slow evolution of relative intelligence in response to environmental
- Species diversification aids the development of intelligence
- Fossil record and encyphlization level
- Is there intelligent life on the Earth?
- How do we define intelligence?
- Grid Patterns 'R Us.
The Electronic Universe Project