Five interacting components:

2.   Atmosphere: gases surrounding earth

3.   Hydrosphere: surface water and groundwater

Closed: Boundaries allow exchange of energy but not matter

Open: exchange both matter and energy

• Receives energy from sun and radiates energy to space. 
• Some matter exchanged: losses of atmospheric gases to space; additions of space material from meteors.
• Amount of matter exchanges negligible in relation to size of earth
• Changes within system eventually affect other parts of system

Response to disturbance where output of sustem also acts as input to system

• Amplifies or dampens response to initial change

Two types: Positive and Negative

Positive: Response to change is strengthened or amplified

• Destabilize system and maximize or promote change

Drives system away from initial state, which produces a larder increase or decrease.

Negative:  Response to change weakened or dampened

• Stabilize system and minimize or resist change
• Drives system back towards original state
• Produces smaller increases or decreases

+ Feedbacks

How it works and Examples

Positive Feedback: response is strengthened

  Examples: ice albedo feedback, water vapor feedback

If all feedbacks positive: climate would be unstable and prone to rapid and large amounts of change

- Feedbacks

How it works and Examples

Negative feedback: response to change is weakened, returning system to original state

Example: rock-weathering feedback

Forces warmer climate, evaporation and precipitation increased, weathering of rocks increased and removes CO2 from atmosphere. Less CO2 in atmosphere cools climate. 

Nebula of gas and dust was left by supernova, gravitational attraction caused nebula to contract.

High P/T at center caused nuclear fusion to begin which formed the sun.

Condensation of remaining material around early sun.

High -temperature condense rocky material (Si, O, Fe, Ni) closest to Sun

Low-temperature condense gases (H, He) farther from Sun

Place rock units and geological events in chronological order

Superposition- rock layers deposited in order from oldest at bottom to youngest at top

Correlation- recognition of rocks in different areas as equivalent in age based on presence of similar fossil types

Numerical ages in years determined using radioactive decay

Decay occurs at specific rate for each isotope – half-life

Result of accretion

-Kinetic energy converted on impact to heat

-Resulted in melting of inner planets

Molten Earth segregated into layers of different densities

• Heavy elements sank to form core: iron
• Lightest elements rose to form cruse: Si, O, AL, Na, K, Ca
• Intermediate mantle between: Mg, Si, O, Fe

Crust

Mantle 

Core

Continental Crust: Thicker (20-70 km), less dense, Si, O, AL, K, Na. Less like mantle. GRANITE

Oceanic Crust: Thinner (10Km) more dense, Si, O, Al, Ca, Mg, Fe. More like mantle. BASALT

Proximity to melting point determines how material behaves:

• Fit of coastlines
• Distribution of fossils
• Similar types/ages of rocks on widley separated coastlines

• Mid-ocean ridges- run through all ocean basins
• huge underwater mountain ranges
• trenches - near some coastlines

Discovered by relationship of deep earthquakes to trenches.

Earthquakes get deeper with distance from trench

Volcanoes concentrated in chains next to trenches

They occur above depth where subducting crust causes melting in mantle

But interactions between plates at plate boundaries results in

• Ridges
• Crust pulled apart
• magma by decompression melting in asthenosphere
• cools to make new oceanic crust

• two plates collide with each other

Convergent plate boundaries

subduction zone

• denser plate subducted
• melting in mantle by addition of water from subducted plate
• trench and volcanic arc- chain of volcanoes on overriding plate
• earthquakes

Convergent plate boundaries

collision zone

• between plates too buoyant to subduct
• crust thickened and mountains raised instead
• earthquakes but no volcanoes

oblique motion between plates - without convergence or divergence

faulting and earthquakes; no volcanism

Divergent

Convergent

Transform

Hotspot

Subduction zones: factories that make continental crust

Accretion of buoyant materials as oceanic crust subducted which builds continent outward over time.

melting of subducted plate and mantle:

erupted at surface or emplaced within crust intrusions. 

crust heated by upwelling mantle; causing uplift

uplift collapses and forms rift valley

rift floods and forms narrow sea

widens by seafloor spreading

1. right distance from sun
2. enough gravity
3. hot interior, active tectonics
4. recycles earth materials
5. molten metallic outer core and fast rotation

1. metabolize
2. grow
3. self-replicate
4. evolve

stores information as base sequences

Passes plan for organization, growth, and reproduction to next cell

1. double Helix
2. Two polymers; alternating sugar and phosphate molecules
3. connected by paired bases; organiz compounds containg nitrogen, guanine pairs with cytosine, thymine pairs with adenine

Only found in living organisms.

L-amino acids absorb less light, thus remain stable.

Only allow interaction with other L acids

Organic molecules formed by reaction of simple molecular building blocks concentrated on ocean surface. 

Experiments show amino acids can be produced from chemical reactions involving gases present in early atmosphere

Organic molecules at ocean surface destroyed by UV radiation. 

Early atmosphere had no free oxygen so no ozone layer

Life originated elsewhere

Arrived already made via comets or meteorites

Meteorites and comets contain organic molecules including amino acids

doesnt explain how or where life formed, only how it came to be on earth

Same conditions needed for life on earth also needed in life originated elsewhere

Early life forms evolved around submarine hydrothermal vents.

Reduced sulfur compounds for energy

Protection from UV radiation

Archaebacteria are most primitive life forms on earth and closest living link to ancestors of all life

Found today at hot springs and vents