Energy flow in ecosystem

First Law of Thermodynamics energy can neither be created nor destroyed but
only is transformed from one form to another.
10 Percent Rule of Energy
As a rule of thumb, 90 percent of the energy involved is degraded at each
trophic transfer and only 10 percent of the energy is conserved in the
organism's tissue.

                                  Ecological pyramids

The graphical representations of different trophic levels in an ecosystem
where producers occupy the base and the top consumer occupy the apex of
the pyramid, is known as ecological pyramid .
They are used to illustrate the feeding relationships between organisms.
Food chains and food webs do not give any information about the numbers
of organisms involved.
This information can be shown through ecological pyramids.
Types of Ecological Pyramids
•Pyramid of number
•Pyramid of biomass
•Pyramid of energy

           Pyramid of Number

 Pyramid of number is used to show the number of individuals in each
trophic level.
 It is upright in case of grassland and pond ecosystems.

         Pyramid of Biomass

Pyramid of biomass records the total dry organic matter of organisms at
each trophic level in a given area of an ecosystem.
The pyramid of biomass is used to show the total biomass of individuals at
each trophic level.
It is better than the pyramid of number for showing the relationships between
organisms.

         Pyramid of energy

 Pyramid of energy is used to show the amount of energy transferred
between trophic levels.
 It provides the best representation of the overall nature of an
ecosystem.
 The pyramid of energy flow is always upright because there is
always loss of energy while moving from lower trophic level to
higher trophic level.
 Therefore, the energy reaching the next trophic level is always less
compared to that in the previous trophic level.