Unit 4: Earth Systems and Resources

Unit 4: Earth's Systems and Resources

Big Ideas

  • Earth's systems interact and influence one another, maintaining a dynamic equilibrium.
  • The majority of atmospheric and Earth surface processes are driven by solar energy.

4.1 Plate Tectonics

  • Theory of Plate Tectonics: The theory states that Earth's lithosphere is broken into plates that move over the asthenosphere.
    • Core:
    • Dense, metallic center of the Earth.
    • Inner Core: Solid
    • Outer Core: Liquid
    • Mantle:
    • Semi-solid layer beneath the crust.
    • Convection Currents: Drive plate movement.
    • Crust: Thin, outermost layer of the Earth.
    • Lithosphere: Rigid outer layer (comprising the crust and upper mantle).
    • Asthenosphere: Semi-molten layer beneath the lithosphere that allows plates to move.
    • Magma: Molten rock that exists beneath Earth's surface.
Plate Boundaries
  • Convergent: Plates collide, leading to the formation of mountains, volcanic activity, and earthquakes (subduction zones).
  • Divergent: Plates move apart, resulting in seafloor spreading and the formation of rift valleys.
  • Transform: Plates slide past each other, causing earthquakes.
  • Subduction: One plate sinks beneath another.
  • Seafloor Spreading: The creation of new crust at mid-ocean ridges.
  • Island Arcs: Volcanic islands formed from oceanic convergence.

4.2 Soil Formation and Erosion

  • Weathering: Breakdown of rock into smaller particles.
    • Physical Weathering: Includes freeze-thaw cycles and abrasion.
    • Chemical Weathering: Includes processes like acid rain and oxidation.
  • Erosion: The transport of soil by wind, water, ice, or gravity.
  • Deposition: The settling of eroded materials.
    • Parent Material: The original rock from which soil forms.
Soil Horizons
  • O Horizon: Organic material composed of decomposed plants and animals.
  • A Horizon: Topsoil with high biological activity, rich in nutrients.
  • B Horizon: Subsoil characterized by mineral accumulation.
  • C Horizon: Weathered parent material.

4.3 Soil Composition and Properties

  • Porosity: The amount of pore space in soil.
  • Permeability: The ability of soil to absorb water.
  • Fertility: The capacity of soil to support plant growth.
  • Water Holding Capacity: The ability of soil to retain moisture.
Soil Texture
  • Sand: Large particles, high permeability, low fertility.
  • Clay: Small particles, high permeability, low fertility.
  • Silt: Medium particles with moderate properties.
  • Loam: Balanced mixture of sand, silt, and clay, ideal for agriculture.
  • Soil Texture Triangle: A tool used to classify soil types based on their texture.

4.4 Earth's Atmosphere

  • Composition:
    • Nitrogen: 78% of the atmosphere.
    • Oxygen: 21% of the atmosphere.
    • Trace Gases: Including carbon dioxide and water vapor.
Layers of the Atmosphere
  • Troposphere: Weather occurs in this layer.
  • Stratosphere: Contains the ozone layer, which absorbs and scatters ultraviolet solar radiation.
  • Mesosphere: Meteors burn up at this level.
  • Thermosphere: High-energy radiation is absorbed here.
  • Exosphere: The outermost layer of the atmosphere.

4.5 Global Wind Patterns

  • Coriolis Effect: The deflection of wind patterns due to Earth's rotation.
  • Convection Cells: Circulation patterns in the atmosphere.
    • Hadley Cells: Located between 0° and 30° latitude.
    • Ferrel Cells: Located between 30° and 60° latitude.
    • Polar Cells: Located between 60° and 90° latitude.

4.7 Solar Radiation and Earth's Seasons

  • Insolation: The incoming solar radiation received by Earth.
  • Albedo: The reflectivity of Earth's surface, affecting temperature and climate.
  • Seasons: Caused by the tilt of Earth's axis and its orbit around the sun.
    • Solstice: Marks the longest and shortest days of the year.
    • Equinox: Occurs when day and night are approximately equal in length.

4.8 Earth's Geography and Climate

  • Weather: Refers to short-term atmospheric conditions.
  • Climate: Refers to long-term weather patterns.
  • Rain Shadow Effect: Dry conditions occur on the leeward side of mountains due to orographic lift.
  • Gyres: Large ocean current systems that redistribute heat throughout the oceans.

4.9 El Niño and La Niña

  • ENSO (El Niño Southern Oscillation): A climate interaction pattern involving ocean-atmosphere interactions in the Pacific Ocean.
    • El Niño: Characterized by warmer Pacific waters leading to altered weather patterns.
    • La Niña: Associated with cooler Pacific waters and increased upwelling of nutrient-rich deep water, influencing global weather systems.