ECOLOGICAL PYRAMID – Graphical representation of the relationship between the
living organisms at different trophic levels.
Charles Elton- developed the concept of pyramid numbers.
G. Evelyn Hutchinson and Raymond Lindeman – they both developed the idea of
pyramid of Energy.
Parasites are organisms that feed or live on other organisms called the host.
Hyper parasites are those parasites that live or feed on other parasites.
PYRAMID OF ENERGY
Pyramid of energy is the only type of ecological pyramid, which is
always upright as the energy flow in a food chain is always
unidirectional. Also, with every increasing trophic level, some
energy is lost into the environment.
PYRAMID of BIOMASS
In this particular type of ecological pyramid, each level takes into
account the amount of biomass produced by each trophic level.
The pyramid of biomass is also upright except for that observed in
oceans where large numbers of zooplanktons depend on a
relatively smaller number of phytoplanktons.
Biomass - the total quantity or weight of organisms in a given area
or volume.
Note : There are two major types of ecological pyramid of biomass
and numbers.
1. Upright - number of individuals or organisms at each
trophic level decreases as you move up the food chain.
2. Inverted - the number of individuals at higher trophic levels
is greater than at lower trophic levels.