Our Solar System
The Hypothesis of the Solar Nebula:
1) Nebula: interstellar cloud, stable.
2) Rotation
3) Mmost of the mass collapses to the center protosun
4) Contraction, heating fusion our sun shines!
5)a) Volatiles condense in outer disc, forming the Jovian Planets:
gaseous, large, low density, many moons
b) Metallic, high melting point materials condensed closer to
the sun, forming planetesimals (pieces of rocks, the parent material of
planets)
Planetesimal accretion Terrestrial Planets: heavier,
rocky, smaller, few moons
6) Earth evolution: Heat meteorite collisions
gravitational pull => compression
radioactive decay
Differentiation molten stage
Heavy elements (Fe Ni) sink
forming the CORE,
Ssilicates of Mg & Fe (lighter materials)
form the MANTLE around it
Outermost layer: Lightest silicates CRUST
(silicates of Al, Fe, Ca, K, Na & Mg)
Outgassing of atmosphere => precipitation => the oceans
LIFE ON EARTH
Where did life first appear?
How did life evolve?
First vertebrates. When did they appear?:
What important evolutionary steps allowed vertebrates to conquer all
the environments?What was needed?
First attempts out of the water: When, who?
Why didn't they succeed?
Successful land conquerors: When, who?
Why did they make it?
What was their demise? When?
Who took over? When?
What about us?
The scientific method:
The tool to discover basic scientific principles
A Hypothesis: a tentative explanation for observed facts. Needs
testing. Experiments are designed to test it.
A THEORY: a widely accepted explanation for observed phenomena.
Thoroughly tested and strongly supported by evidences from different fields.
It is the highest category of scientific knowledge.
Population
Natural systems are in equilibrium, small disruptions are compensated.
Large disruptions may permanently change the equilibrium.
Population dynamics: studies how population grows
Earth's carrying capacity: the number of individuals the
earth can support. It is a limited number when resources do not increase
at the same rate as demand.
Population growth rate: is a percentage that the number
of people born at any year represent from the total population
of that year - World: 1.6%; U.S.= 0.7%
Doubling time
Doubling time: 70 ÷ growth rate (%)
For U.S. Doubling time: 70 ÷ 0.7 = 700 ÷ 7 = 100
Population growth curve is exponential
Estimates for 2050 = 9-15 billion people
problems = erosion
deforestation
greenhouse effect
ozone depletion
decrease of diversity
depletion of resources
How does geology help?
Problems with experiments?
Problems with rock's interpretation?
Environmental geology: Focus?
goals: Identify geologic hazards to prevent them
Prospect for resources
Solve stablished problems
Surveying maps planning
Use previous experiences wisely
Assess impact of developments
all tied to population growth
EARTH RESOURCES AND ENVIRONMENTS
CHAPTER I : An Overview of Our Planetary Environment
1. Explain the origin of the Universe.
2. Explain the formation of our solar system.
3. How and why did it give rise to so
different planets as Jupiter and Mercury?.
4. Explain accretion.
5. What do we (geologists) understand by earth differentiation.?
6. Chemical composition and structure of the Earth.
8. Composition of the Jovian planets and the Terrestrial planets.
9. How did the oceans form?
10. How did the atmosphere evolve? Compare the composition of the early
atmosphere with that of today's atmosphere.
12. Atmosphere of Venus?
13. Atmosphere of Io and Ganymede? (Just kidding!)
14. Life on earth: all.
15. Know the definitions of population growth rate,
doubling time, earth's carrying capacity. Know areas of current high
and low growth rates. Approximate current world and U.S. values for
the terms defined above.
16. The scientific method. Problems geologists run into when
trying to apply it.