Food Chain is the interactions between various living organisms on the basis of their food priority, ie., who eats whom. It can be either grazing food chain (starts from producers), parasitic food chain (starts for host) or deteritus food chain (starts form dead organic matter).
Food Web represents the interconnected network of different food chains in an ecosystem.
Energy flow : Sun is the ultimate source of energy for all ecosystem except deep thermal vents.
All producers convert sunlight energy into chemical energy by photosynthesis and produce food. It acts as a source of energy for all consumers and decomposers in food web.
In an ecosystem, energy flow is always unidirectional and a food chain only has 3-4 trophic levels.
Decomposition : It is degradation of dead organic matter and recycling of nutrients with the help of decomposers.
Nutrient Cycle : It is the flow of various nutrients in ecosystem. in different forms from one biotic/abiotic component to another one in a cyclic pattern. It is also known as biogeochemical cycle.
Nutrients get recycled decomposers. It has following three types by
Water cycle
Gaseous cycles, e.g. nitrogen, carbon or oxygen cycle.
Sedimentary cycles, e.g. sulphur or phosphorus cycle.
Ecological Succession : It refers to a phenomenon by which an ecological community undergoes orderly and predicatable changes following a disturbance or the initial colonisation of a new habitat.
Ecological Pyramids : It is the graphical representation in pyramidal form of the trophic structures of an ecosystem. It is based on factors such as number of organisms, biomass or total amount of energy transferred from one trophic level to the next.
Biological Interactions : These are the interactions between various organisms, which can be of following types.
Positive interactions where one (commensalism) or both (mutualism or symbiosis) organisms are benefited.
Negative interactions where one inflicts harm on other without getting any benefits (amensalism) or one benefits at the expense of another (parasitism and predation).
