//Food Chains -- The transfer of energy in the form of food, starting from producer and ending at consumers or detritivores or decomposers is known as food chain. It is linear network of links in a food web.  It also shows how the organisms are related with each other by food chains.

  In an ecosystem we found two types of food chain..    a// Grazing Food Chain -- It starts from living green-plants, goes to grazing herbivorous and on to carnivores.    For ex-  Grass----> Mouse ----> Snake ----> Hawk 
   b// Detritus Food Chain -- It starts from dead organic matter, goes to detritus feeding organism and on to their predators.    For ex-  dead plants ----> soil mites ----> insects ---> Birds   // Food Web -- All the food chains in nature never operates as isolated sequence, rather they are interconnected with each other, forming interlinking patterns of food chains, known as food web or food cycle.     When several food chains are connected, food web id formed. It can also be said as a graphical representation of who-eats-whom.     For ex-- In a grasslands ecosystem there may be six linear food chains as follows,     i.    Grass ----> Grasshoppers ----> Lizard ----> Hawk   ii.   Grass ----> Mouse ----> Snake ----> Hawk   iii.  Grass ----> Grasshoppers ----> Lizard ---->Snake ----> Hawk   iv.  Grass ----> Mouse ----> Hawk     when the above three are connected, it forms a food web.        //Ecological Pyramid -- Ecological pyramids are of three types.     a// Pyramid of Numbers -- It shows the number of producers, carnivores, herbivorous present at each tropical level of an ecosystem. Generally ecosystems have more producers than consumers, but in some cases it's opposite and it causes inverted pyramid.     For ex -- examples of pyramids   [FIGURE]     b// Pyramid Of Biomass -- It shows how much biomass i.e. the amount of organic matter present in the organisms of at each tropical level of an ecosystem.     For ex- In grasslands of forest ecosystem, there is gradual decrease in biomass forming upright pyramid, where as in pond ecosystem producers are small, hence producing less biomass, which cause inverted pyramid.           [FIGURE]     c// Pyramid Of Energy -- It shows how much energy is transferred to next tropical level from producers to consumers.  When energy is transferred to the next tropical level, only 10% of energy is passed on (10% rule). Its shape is always upright, as there is a gradual decrease in the energy content from producers to consumers.   For ex- Producers -----> Herbivorous -----> Primary Consumers -----> Secondary Consumers -----> Tertiary Consumers -----> Top Consumers   [FIGURE]  //Photosynthesis -- It is the process by which green-plants and other organisms make food using sunlight, water and carbon dioxidexx