1.The transfer of food energy through a sequence of eating and being eaten by the organisms in an ecosystem is termed as the food chain.
2.The position of organisms along a food chain is referred to as trophic level.
3.Energy transfer efficiency limits food chain lengths. The shorter the food chain -or nearer the organism to the producer trophic level –greater will be the energy available at that population.
4.Grazing food chain starts from the green plants, the major source of energy for this chain is taken from the sun as the plants carry out the process of photosynthesis in the presence of sunlight.
5.The detritus food chain starts from the dead organic matter such as dead bodies of animals or fallen leaves, which are eaten by microorganisms and then followed by detritus feeding organisms (detritivores) and their predators.
6.A food web can be defined as a network of food chains interconnected to each other so that a number of options of eating and being eaten are available at each trophic level.
7.Based on how the species influence one another in a community, food webs are of three types-Connectedness webs, Energy flow websand Functional webs.
8.Food webs have been found to involve much more than ‘who eats whom’-an effect known as Reward feedback.It has been seen that when a downstream organism in an energy flow has a positive effect on its upstream food supply, in the sense that a consumer (such as herbivore or parasite) does something that sustains the survival of its food resource.
9.Food webs can also be used to illustrate indirect interactions among species. When the impact of a predator on its prey’s ecology tricklesdown one more feeding level to affect the density and/or behaviour of the prey's prey, ecologists term this interaction a feeding, or trophic cascade.
10.There are two approaches by which food webs can be used to study the control of community structure -bottom-up or top-down approach.
11.Biological magnification refers to the process whereby certain substances such as pesticides or heavy metals become concentrated in successive trophic levels in a food chain