Until a few years ago it was
thought that the sun supplied energy for all life. Researchers
have discovered, however, that certain microscopic organisms do not get
their energy from the sun but obtain it from inorganic sources.
Perabacterium spelei, for example, derives its energy from iron
carbonate (FeCO2) which is plentiful in its physical
environment-limestone caves. Life a green plant, it uses inorganic
matter (carbon from the mineral and nitrogen from the air) to produce
its food, Niphargus, a tiny, blind crustacean, consumes this
organic food and is, in turn, eaten by larger animals. Al this
takes place where chlorophyll-bearing plants do not exist and where
sunlight never reaches. P. spelei is, therefore the first link in
this particular food chain.
Food chains, as you already
know, being with producers. Produces need certain materials and a
source of energy in order to manufacture food. In some instances,
the source of energy is the inorganic matter used by the organism.
In most instances, however, the source of energy is the sun. In
fact, the sun has supplied the energy for almost all life since life
began on this earth. Its role and its great importance shall
always be emphasized.