Module 3

• Energy


  The ability to do work
• Forms of energy


  • Mechanical (kinetic and potential)
  • Radiant
  • Sound
  • Chemical
  • Heat
  • Electrical
  • Nuclear
• Renewable and non-renewable energy sources

  Renewable sources can be replenished, non-renewable sources cannot
• Laws of Thermodynamics


  • 1st law: Energy cannot be created or destroyed, only converted from one form to another
  • 2nd law: Disorder (entropy) in the universe is increasing, as energy is used more of it is converted to heat
• Primary source of energy

  The sun
• How energy is acquired by living things

  1. Photosynthesis

  2. Chemosynthesis

  3. Eating/digesting other organisms

  
• Photoautotrophs


  Organisms like plants, algae and photosynthetic bacteria that harness radiant energy and convert it to chemical energy

  
• Chemoautotrophs


  Organisms that create organic food from inorganic chemicals
• Heterotrophs


  Organisms that cannot capture light or chemical energy to make food and rely on autotrophs
• Trophic levels


  Feeding levels in a food chain or web, with primary producers at the bottom and higher level consumers above
• Only about 10% of net energy production at one trophic level is passed on to the next level
• Ecological pyramids


  Graphical representations showing relationships between energy and trophic levels in an ecosystem
• Biological magnification or biomagnification is the increasing concentration of persistent, toxic substances at each trophic level
• Energy flows in one direction through ecosystems, entering as sunlight/inorganic molecules and leaving as heat
• Biogeochemical cycles


  The recycling of inorganic matter between living organisms and their environment
• Functions of biogeochemical cycles

  • Enable transformation of matter
  • Enable transfer of molecules
  • Facilitate storage of elements
  • Assist in the functioning of ecosystem
  • Link living to non-living components and living to living components
  • Regulate flow of substances
• Key elements in biogeochemical cycles

  • Hydrogen
  • Oxygen
  • Carbon
  • Nitrogen
  • Phosphorus
• Human activities can influence and hasten biogeochemical cycles
• Common part of Biogeochemical cycle

  1. Radiant energy as power
  2. Reservoir (storage of chemicals)
  3. Function on both local and global levels (linking ecosystem)
• Closed system


  elements are recycled and replenish w/o outside forces