Function of an ECOSYSTEM Functional Attributes Ecosystem performs

Function of an ECOSYSTEM

Functional Attributes • Ecosystem performs under natural conditions in a systematic way. • Energy, various nutrients and water are required for life processes which are exchanged by biotic components within themselves and with abiotic components.

The major functional attributes of an ecosystem are as follows a) Food chain, Food webs, trophic structure b) Energy flow c) Cycling of nutrients(Biogeochemical cycles) d) Primary & Secondary production e) Ecosystem development & regulation

Trophic Structure • The structure and function of ecosystem are closely related so, they need to be studied together. • The flow of energy is mediated through a series of feeding relationships in definite sequence known as food chain.

• The producers and consumers are arranged in ecosystem in a definite manner and they interaction along with population size are expressed together as trophic structure. • Each food level is known as trophic level and the amount of living matter at each trophic level at a given time is known as standing crop or standing biomass.

E N E R G Y Trophic Levels Tertiary consumers - top carnivores Secondary consumerssmall carnivores Primary consumers- Herbivores Producers- Autotrophs

Food Chain • The sequence of eating and being eaten in an ecosystem is known as food chain. • All organisms, living or dead, are potential food for some other organism and thus there is essentially no waste in the functioning of natural ecosystem. • e. g. , grass-> grass hopper-> frog-> snake -> hawk(grass land ecosystem)

Types of food chains • Two major types of food chains ØGrazing food chain It starts with green plants and culminates in carnivores. Eg: grass-> rabbit-> fox. ØDetritus food chain it starts with dead organic matter which the detritivores and decomposers consume Eg: leaf litter-> algae-> crabs-> small fish-> large fish.

Food Web • Food web is a network of food chains where different types of organisms are connected at different trophic levels, so that there a No: of options for eating and being eaten at each trophic level. • the ecosystems are much more complex, they have rich species diversity and therefore food webs are much more complex.

Food chain (just 1 path of energy) Food web (all possible energy paths)

Why food web instead of Food chain • Food webs give greater stability to the ecosystem. • In food chain if one species becomes extinct or one species suffers then the subsequent species in trophic level also affected. • In food web, there are No: of options available at each trophic level so if one species is affected it does not affect other trophic level.

Significant of food chain and food web • Food chain & food web play a significant role in ecosystem because, the important functions of energy flow & nutrient cycling takes place through them. • Food chains help in maintainindg and regulating the population size of different animals and thus maintains the ecological balance.

• Food chains show a unique property of biological magnification of some chemicals • There are several pesticides, heavy metals and other chemicals which are nonbiodegradable in nature. Such chemicals are not decomposed by micro organisms & they keep on passing from one trophic level to another. And, at each successive trophic level they keep on increasing in concentration. This phenomenon is called Biomagnifications or Biological magnification