The FOOD WEB of an ecosystem reflects its energy transfers, with producers, consumers and decomposers all contributing to the flow of energy and nutrients through the system.

BIOGEOCHEMICAL CYCLES: IT'S ALL CONNECTED!


  • Producers are autotrophs which make their own food, usually via photosynthesis.
  • Consumers are heterotrophs, which eat other organisms for energy.

    Each of these types of organisms occupies one or more trophic levels, depending on what it eats. The lowest levels in the food web have the most organisms, and the higher you go in the food web, the fewer organisms there are.

    For example, there are more flies than frogs, and more frogs than garter snakes. The highest trophic level (top carnivores) generally has the fewest individuals. This is a reflection of the ENERGY FLOW in the ecosystem.

    ENERGY is only one thing that cycles through ecosystems.

    Inorganic NUTRIENTS and WATER also cycle through ecosystems.

    ...In other words, any substance that passes through living things can cycle through the biosphere.

    In these cycles, the nutrients may pass through

  • SOLID
  • LIQUID
  • GASEOUS

    ...phases

    These nutrients pass through both living organisms and non-living earth. This is why the cycles they go through are called BIOGEOCHEMICAL CYCLES.

    I could show you a whole array of biogeochemical cycles, but I'll concentrate mainly on two of them today...

  • The Hydrologic Cycle: Cycling of water through biotic and abiotic ecosystem components
  • Carbon Cycle: Cycling of carbon through biotic and abiotic ecosystem components

    Let's look at pictures of these cycles and follow where these substances go. Note the names of the processes as we go along, and be sure you know the meaning of:

  • transpiration
  • evaporation
  • precipitation
  • percolation
  • fossilization

    Your text has illustrations of other types of biogeochemical cycles.

    Be sure to know the difference between The Greenhouse Effect and Global Warming, the thinning of the Ozone Layer and what these have to do with the Carbon (and Hydrologic) cycles!