Food Chains and Webs
                Every organism has a job (niche) in the ecosystem:

producer (the autotrophs): use sunlight or some other form of
    energy to create food energy  (usually via photosynthesis)
        6CO2 + 6H2O--> C6H12O6 + energy + 6O2

consumer (the heterotrophs) there are many other niches (predator, herbivore,          carnivore, etc.). use food to create cell energy (by cellular respiration)
            C6H12O6 + 6O2 + energy --> 6CO2 + 6H2O + more energy (ATP)

decomposer these organisms process dead material and return nutrients to the soil

                Every organism has an address (habitat) specific to it:
                            top of the tree, deepest ocean, etc.

A food chain is a diagram of the flow of energy in an ecosystem from producer to consumer.  It shows the niches of the organisms involved.  All food chains begin with the sun.  Arrows mean "is eaten by".   Example=
            sun-->grass-->grasshopper-->frog-->great blue heron-->bacteria
                (producer) (consumer,    (cons.,    (consumer,             (decomposer)
                                prey,herbi-     predator    carnivore
                                 vore)             carnivore)     predator)

The chain of energy is passed throughout the food chain.
~this is too simplistic, not like real life~

A food web is a more accurate indication of what happens in an ecosystem.  The more complex the food we, the healthier the ecosystem...Why?