By observing the numbers and sizes of the
organisms in food chains we can find out what
happens to energy and biomass as it passes along
the food chain.
Radiation from the Sun is the source of energy for most communities of living organisms. Green plants and
algae absorb a small amount of the light that reaches them. The transfer from light energy to chemical energy
occurs during photosynthesis. This energy is stored in the substances that make up the cells of the plants.
The mass of living material (biomass) at each
stage in a food chain is less than it was at the
previous stage. The biomass at each stage can
be drawn to scale and shown as a pyramid of
biomass.
The amounts of material and energy
contained in the biomass of organisms is
reduced at each successive stage in a food
chain because some materials and energy are
always lost in the organisms' waste materials
and respiration supplies all the energy needs
for living processes, including movement.
Much of this energy is eventually transferred
to the surroundings.
The first group of organisms in a food chain, plants, are known as the
primary producers. Those who then eat the plants are called the primary
consumers. The next stage of the food chain involves the secondary
consumers and after that, the tertiary consumers.