Energy Flow through Food Chain

Food Chain: 

The food chain refers to the series of feeding groups of organisms that transfer nutrients and energy to one another. The food chain is a diagram that shows how energy moves linearly from an organism at one trophic level to another at a higher level.

Kind of Food Chain :

Grazing Food chain: 

It starts from autotrophs & energy usually comes from the sun. 

• In an aquatic ecosystem, the grazing food chain is the major conduit for energy flow. 
• In Terrestrial Ecosystem the food chain cycle follow as –  Plant → Caterpillar → Lizard → Snake and so on.
• Aquatic Ecosystem follows –  Phytoplankton → Zooplankton → Fish → Pelican. 

Detritus Food chain: 

• It begins with dead organic matter (fallen leaves) that is consumed by saprotrophic (detritivorous) organisms such as bacteria, fungus, and protozoans. Detritus Food Chain is a significant energy conduit in the terrestrial ecosystem. 
• Example: Litter → Earthworms → Chicken → Hawk.  

Trophic levels :

• 80 to 90 percent of an organism’s energy or biomass is lost during each trophic level (10 percent energy transmitted) as heat energy. As a result, the length of the food chain is restricted to 4-6 trophic levels.
• A single organism may occupy more than one trophic level at once because the term “species” is not used in the trophic level definition. As an illustration, a sparrow is a primary consumer when it consumes seeds and fruits but a secondary consumer when it consumes insects.
• Bioaccumulation & Biomagnification are two processes used to transport non-degradable contaminants (chlorinated hydrocarbons) through the trophic level.

Bioaccumulation :

It is the process through which pollutants enter the food chain, from the environment to the first organism at a given trophic level. It symbolizes the movement of harmful material up the food chain from one organism to another. Nonylphenol is an example. 

Bioconcentration :

It means, the intake and retention of material in an organism solely through breathing air or water in a terrestrial or aquatic setting. Similar to bioaccumulation, but with a different cause. 

Biomagnification :

It is a rise in toxin concentration in a food chain at multiple trophic levels rather than in an organism. Over time, heavy metals or harmful substances slowly accumulate inside organisms. This means that the most amount of poison is present at the top level. Pollutants must be mobile, soluble in fats, physiologically active, and long-lived for bio-magnification to occur. Examples include mercury through fish, Radioactive isotopes from soil contamination, PCB, and cyanides. DDT caused eagle eggs to have incredibly thin shells and eggs shattered before they could hatch.  
 

Food Web :

A web or network of food chains is what the term “food web” refers to when describing the feeding relationships within a community. The more intricate the food web, the more stable it will be because if one species disappears, another could fill its place and preserve balance (simple & smaller prone to extinction).

Communities of living things and their physical surroundings interact as an ecological unit within an ecosystem, which is a structural and functional unit of the biosphere. As a result, an ecosystem also contains non-living elements.
The three areas of study for ecosystem function are:

1.  Energy flow: Food Chain, Trophic Level, Ecological Pyramid. 
2.  Nutrient Cycle: (Bio-Geo chemical Cycle). 
3.  Ecological Succession