Envi Sci

• ENVIRONMENTAL SCIENCE - Field of science that studies the interactions of the physical, chemical, and biological components of the environment and the relationship and effects of these components with the organisms in the environment
• ECOLOGY - Study of the relationships among organisms and their environment
• LEVELS OF ORGANIZATION

  • Biosphere

  • Biome

  • Ecosystem

  • Community

  • Population

  • Organism/individual
• BIOSPHERE

  • The entire living part of Earth's crust; all life on earth
  • made up of the parts of Earth where life exists
• ECOSYSTEM - All the interacting organisms and their physical environment within a given area
• Biome - major regional or global community of organisms characterized by

  the climate conditions and plant communities that thrive there
• Population - group of individuals of the same species occupying a particular habitat at a particular time
• ECOSYSTEM - Includes both living (biotic) and non-living (abiotic) factors
• Community - A collection of populations of different species, which live together in an ecosystem.
• KEYSTONE SPECIES - Have an unusually large effect on its ecosystem
• BIOGEOCHEMICAL CYCLES - Most common elements associated with organic molecules

  1. Hydrological Cycle
  2. Carbon Cycle
  3. Nitrogen Cycle
  4. Phosphorus Cycle
  5. Sulfur Cycle
• Water Cycle - Water from the land and oceans enters the atmosphere by evaporation or sublimation, where it condenses into clouds and falls as rain or snow.
• Carbon Cycle - Carbon is cycled between the biosphere, lithosphere, hydrosphere, and atmosphere through photosynthesis, respiration, decomposition, combustion, weathering, erosion, sedimentation, fossilization, and volcanic activity.
• Long-term storage of organic carbon occurs when matter from living organisms is buried deep underground and becomes fossilized. Volcanic activity and, more recently, human emissions bring this stored carbon back into the carbon cycle.
• Fixation - N2 gas converted to ammonia (NH3)
• Ammonification - Decomposition of dead plant/animal material releases ammonium (NH4+).
• Human activity can alter the nitrogen cycle by two primary means: the combustion of fossil fuels, which releases different nitrogen oxides, and by the use of artificial fertilizers (which contain nitrogen and phosphorus compounds) in agriculture, which are then washed into lakes, streams, and rivers by surface runoff.