v A food chain may be defined as, “the transfer of energy and nutrients through a series of organisms with repeated process of eating and being eaten”.
v In an ecosystem, all the organisms are linked together with one another by food relationship.
v Each organism living or dead is potential food for some other organism.
v Under natural conditions, the linear arrangement of food chains hardly occurs & these remains connected interconnected with each other through different types of organisms.
v Interlocking pattern of several interlinked food chains is termed as FOOD WEB.
v An”Ecological pyramid” is a graphical representation that shows the relative amounts of energy or matter contained within each tropic level in a food chain or food web.
v An ecological pyramid shows the relationship between consumers and producers at different tropic levels in an ecosystem
v There are three ecological pyramids recognized by ecologists:
1 Pyramid of Numbers
ü Shows the relative number of individual organisms at each tropic level.
2 Pyramid of Biomass
v A pyramid of biomass represents the total dry mass (in grams per square meter of area) of all the organisms in each tropic level at a particular time.
3 Pyramid of Energy
v A pyramid of biomass represents the rate of energy flow and/or productivity at successive tropic levels. The pyramids of energy are always upright.