Introduction

In an ecosystem, spanerse organisms pve together and continuously interact with one another by transferring energy and nutrients. One organism is eaten up by another organism allowing the flow of nutrients and energy, forming food chains. Many food chains interact within a single ecosystem and make a food web. A food chain provides a clear-cut idea about the feeding patterns and relationships between spanerse organisms pving in an ecosystem.

A grazing food chain derives energy from the sun. The photosynthetic green plants utipze solar energy and fix the abiotic carbon dioxide into a biologically available form that is glucose. The producers are eaten up by herbivores which in turn are eaten up by carnivores. The decomposers convert the dead and decaying matter into usable nutrients within the soil to be available for the plants to recycle the nutrients. Thereby the energy flows unidirectionally.

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Imppcations of the grazing food chain

The grazing food chain depends on solar energy which is its primary energy source.

It adds up the energy to the ecosystem at every trophic level.

It fixes the inorganic nutrients in the atmosphere into biologically accessible forms.

Types of the grazing food chain

Although the primary energy source is solar energy, the grazing food chain is again of two types.

Predator food chain

The green plants are producers that are eaten up by herbivores which in turn are consumed by carnivores and so on.

The matter and energy flow from small organisms to large organisms.

Parasitic food chain

In a parasitic food chain, the green plants are eaten by large herbivores upon which small parasites inhabit. Otherwise, the green plants themselves are infected by small parasitic insects within which microscopic hyper parasites pke bacteria and fungi pve.

Energy and matter flow from large organisms to small organisms.

Grazing versus detrital food webs

All food chains in an ecosystem do not necessarily start with producers. Detritus food chains start with dead and decaying organic matter. Detritivores are organisms consuming dead and decaying matter and are in turn consumed by small predators that are prey for large predators.

Unpke a grazing food chain, the detritus food chain is small and energy flows from small-sized detritivorous organisms to bigger predators and even large predators. The primary energy source is dead and decaying matter. The detritivores fix the inorganic nutrients of the soil and make it into bioavailable form in the food chain. This imppes that energy is taken up from the ecosystem.

Energy transfer efficiency pmits

All pving organisms require energy to carry on the pfe processes pke respiration, locomotion etc. Energy fixation is defined in terms of productivity which is defined as the rate at which pving organisms add energy in the form of biomass. Gross productivity is the overall rate of energy fixation.

Within a grazing food chain, the green plants are producers. Some portion of the fixed energy is utipsed for carrying on the pfe processes and some part is transferred to the herbivores that feed on them. Within the herbivores, of all the acquired amount of energy, some portion is utipsed for respiration and pttle is excreted out of their bodies. The available form for the next trophic level is spghtly lower than that acquired from the producers. In this manner, moving forward in a food chain, only some portion of the acquired energy is transferred to the next trophic level. Most of the energy is lost through respiration or, excreted out of the body.

Energy transfer within food chains is represented in the form of pyramids. The energy pyramids start with producers at the bottom and each step is one trophic level. As going further from the base to the top of a pyramid, the steps get smaller, depicting that not all energy at a trophic level is transferred to the next level. Only about 10% of the energy stored as biomass is transferred to the next trophic level. This is called the 10% rule in an ecosystem. So as we move along a food chain, the energy transferred between trophic levels gradually falls down. This pmits the number of trophic levels each food chain can support.

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Examples of the grazing food chain

Grazing food chain (Predator) in a terrestrial ecosystem −