Food Interactions Between Organisms: Understanding Ecological Relationships

 Food Chain:

                    " Flow of energy from one trophic level to other trophic level is called 

food chain".

In other words:

            "Series of step of eating and being eaten is called food chain".

For example: 

             The grasshopper eats grass, rat eats grasshopper, snake eats rat and then snack

 is eaten by eagle. This eating process make a chain which is called food chain. Every

food chain always starts from producers and finish on decomposers.

Trophic level:

             The levels in food chain are called trophic level.
As in above example grass is first trophic level, grasshopper second trophic level, frog third
and so on. There is a change of energy level in each trophic level. This change in energy

state a law which says:
         " The energy is transfer from one trophic level to next level, in each level only 10%

energy is transferred"
. 

Food Web:

    The combination of many food chains is called food web. It is complicated than a single food chain. Because an animal may eat more than one animal. As fox eats rabbit, beetle and also a rat.

Example:

A fox eat rat and also a rabbit. Sparrow eat caterpillar and grass-hopper, cat eat both sparrow and caterpillar this situation make a complicated food web. A primary prey may have more than one predator.

 

 Food pyramid:

        Food pyramid is also known as ecological pyramid which is according to energy
 number and biomass of organisms. When we placed food chain from bottom to top according to their trophic levels, in first trophic level they are large in number but small in size and in last trophic level they are large in size but small in number as shown in figure.
This following figure is known as "food pyramid".

There are three types of food pyramid:

1. Pyramid of Energy:

        The pyramid which shows flow of energy from

 first trophic level to other is called pyramid of energy. It is always bottom to top

 because energy decrease from producers to other.

2. Pyramid of Number:

        The pyramid which is according to number of organisms is called pyramid of number.

It is up right because in first trophic level number of organisms are more than last trophic 

level.

3. Pyramid of Biomass:

        The pyramid which represent total mass of living organism is called pyramid of biomass.

Actually the biomass means  "mass of organism".