FOOD CHAINS

FOOD CHAINS

• The transfer of food energy from the source in plants through a series of organism with repeated eating and being eaten is called a food chain.
• The animal being eaten is called the prey and the animal eating a prey is called the predator.
• There is a tremendous loss of energy at every link of the food chain. In a food chain , an animal passes on only about 10 percent of the energy it receives. About 90 percent of the potential energy is lost as heat.
• The shorter the food chain the more energy is available to orgainsms. Most food chains have no more than four or five links.
•  Food chains are of two types :

1. GRAZING FOOD CHAIN :- This begins with algae and other green plants and ends with a carnivore.
2. DECOMPOSER OR DETRITUS FOOD CHAIN :- This includes orgainsms such as fungi and bacteria that are largely responsible for decomposition.

LINKS OF A FOOD CHAIN

                                                     

1. Primary producer
2. Primary consumer
3. Secondary consumer
4. Tertiary consumer
5. Decomposer

PRODUCER :- Producers are called so because they can produce their own food. In terrestrial ecosystems, producers are usually green plants . Freshwater and marine ecosystems frequently have algae as the the dominant producers.

CONSUMERS :- Consumers depend on others for the food they eat. They may subsist directly on the primary producer or on other consumers.
                       since herbivores take their food directly from the producer level, they are called primary consumers. 

• Animals that eat only plants are called herbivores.
• Animals that eat only other animals are called carnivores.
• Animals that eat both plants and animals are called omnivores.

DECOMPOSERS :- Decomposers are organisms that speed up the decaying process and thus recycle nutrients. These break down non-living organic matter into inorganic matter. 
                  Decomposers help release minerals back into the food chain for absorption by the producers--- the plants.


FOOD WEBS :- One or more interconnected food chains form a food web. A food web is a more realistic and accurate representation of energy flow.  Most animals are part of more than one food chain as they eat more than one kind of food in order to meet their energy requirements.