The Biosphere

• Biosphere: the thin layer of the Earth that has conditions suitable for supporting life.

  • consists of the atmosphere, lithosphere, & hydrosphere

  
• Atmosphere: thing layer of gases that surrounds the Earth

  • composed of nitrogen & oxygen, and trace amounts of other gases
  • can be divided into 4 layers determined by average air temperature
  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere

  
• Troposphere: lowest layer of the atmosphere that contains about 80% of the atmospheric gases

  • 15 degree Celsius - -60 degree Celsius
  • ONLY part of the atmosphere that can support life
  • where most weather occurs

  
• Stratosphere: contains the ozone layer that protects the Earth from radiation

  • -60 degree Celsius - 0 degree Celsius
  • where most aircraft fly at the lower levels
• Mesosphere: where space debris gets destroyed before it can reach Earth's surface

  • 0 degree Celsius - -100 degree Celsius at high altitudes
• Thermosphere: contains very little gases

  • -100 degree Celsius to over 2000 degree Celsius
  • absorbs much of the radiation from the sun
• Hydrosphere consists of the all the water on Earth -- solid liquid and gas.

  • 97% stored water ; 3% freshwater (lakes, rivers, groundwaters, and glaciers)
  • warmed by incoming solar radiation and molten material in the Earth's mantle