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  2. OBJECTIVES 1. Identify the four subsystems of the Earth. 2. Differentiate the four subsystems of the Earth in terms of their composition/structure and boundaries. 3. Explain the energy flow in each subsystem.
  3.  How does Earth maintain its existence and functions?  Through the interactions of its parts called components.  The Earth’s four central components known as subsystems – geosphere, hydrosphere, atmosphere, and biosphere.
  4.  These subsystems are interconnected by the processes and cycles to store, transform and/or transfer energy throughout the whole Earth system.  The energy that drives these processes comes mainly from the Sun.
  5.  Earth’s subsystems are dynamic.  A change in one subsystem may cause change in other subsystems.  Other subsystems’ degree of response may describe how stable or unstable these subsystems are.
  6.  Glacier is relatively unstable.  When the temperature of the atmosphere rises above the melting point of ice, the glacier melts.  Trees and plants are relatively stable.  When there is water shortage, they reduce the size of their stomata to reduce evaporation and maintain its state of equilibrium.
  8.  Geologists and geophysicists study the Earth’s geosphere.  The geosphere extends from the core of the planet all the way to the dynamic crust.  It interacts with the atmosphere and hydrosphere through weathering and erosion.
  9. EARTH’S INTERIOR  Inner core  Radius is 1 300 km.  Solid core due to immense pressure that exists in the center of the planet.  The Bullen discontinuity separates inner and outer core.  Outer core  Radius of 2 250 km.  Liquid layer of the core.  Movement of metallic iron within this zone generates Earth’s magnetic field.
  10. EARTH’S INTERIOR  Gutenberg discontinuity is the boundary between outer core and mantle.  Mantle  Radius is 2 900 km.  Holds more than 82% of Earth’s volume.  Divided into upper layer (lithosphere) and lower layer (asthenosphere).  Magma came from asthenosphere.
  11. EARTH’S INTERIOR  Mohorovicic discontinuity separates the upper mantle and the crust.  Crust  Radius is 8 to 40 km.  Thin, rocky outer skin.  Divided into continental crust and oceanic crust.
  13.  Forces under Earth’s surface cause convection currents to form within Earth’s mantle.  As a result, mountains, trenches, volcanoes, and other landscapes were formed.  Cause volcanic activities, earthquakes, creation of new crust, and destruction of other portions of crust.
  14. Processes that occur in Earth’s Geosphere
  15. Sedimentary rock layer at the Grand Canyon National Park Layer of metamorphic rocks in Marble Canyon, Death Valley, California. Obsidian rocks, Landmannalaugar, Iceland ROCK CYCLE
  17.  Made of several layers of gases that enveloped the planet.  Atmosphere originated from the word atmo (means vapor) and sphaira (means ball).
  18. Importance of atmosphere:  Contains O2, which is vital for living organisms.  O3 found in the atmosphere protects living organisms from harmful UV radiation.  It helps regulate Earth’s temperature.
  19. Importance of atmosphere:  The gases found in the atmosphere are important for many life processes such as photosynthesis and respiration.  Plays a key role in water cycle.
  20. TROPOSPHERE  Lowermost layer.  The term troposphere literally means the region where the air “turns over”.  All important weather phenomena occur.  The higher you go up, the colder you gets.  The uppermost layer of the troposphere is tropopause.
  21. STRATOSPHERE  The ozone is found in this layer.  The temperature increases as the altitude increases.  Jets fly at the bottom of this layer.  Its uppermost layer is called stratopause.  Stratopause separates stratosphere and mesosphere.
  22. MESOSPHERE  The temperature decreases as the altitude increases.  Weather balloons and other aircraft cannot fly high enough to reach this layer.  Satellites orbit above this layer.  Most meteors vaporizes in this layer.  The mesopause is the coldest layer of the atmosphere.
  23. THERMOSPHERE  Contains only a tiny fraction of the atmosphere’s mass.  You get warm as you go higher.  This is the hottest layer of the atmosphere.  The ionosphere is found within the mesosphere and thermosphere.  Many satellites orbit in this layer.
  24. THERMOSPHERE  Auroras happen in ionosphere because charged particles from space collide with the atoms and molecules in the thermosphere, exciting them into high energy states. As a result, those atoms shed excess energy by emitting photons of light.
  25. EXOSPHERE  Thermopause serves as the boundary between thermosphere and exosphere.  The outermost layer.  Separates the rest of the atmosphere from the outer space.  Atoms and molecules easily escape in this layer.