Food web maintains the stability of the eco-system. The greater the number of alternative pathways, the more stable is the community of living things.
In eco-systems, normally the food chains never operate as isolated sequences but are inter-connected with one another forming some sort of interlocking pattern. Such a complicated network of the food relationship and inter-relationship is called as food web. The concept of food-web is useful for analysis of community.
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Under natural conditions, the food chains may not be arranged linearly. That is, a particular organism may not occupy the same trophic level in every food chain. It may simultaneously behave as a secondary, a tertiary or a top consumer. Hence, the food chains are inter-connected with one another through different types of organisms at different trophic levels.
For example, man and many other organisms are at the same time herbivorous and carnivorous and hence occupy different trophic levels in the food chains. In grazing food chain of grassland, in the absence of rabbits, grass may also be eaten by mouse.
The mouse in turn may be- directly eaten by hawks or by snakes first which is then eaten by hawks. Thus, nature has sufficient alternatives which altogether constitute some sort of inter-locking pattern, the food web.
Food web maintains the stability of the eco-system. The greater the number of alternative pathways, the more stable is the community of living things.
A food web in a grass land eco-system is seen to consist of as many as five linear food chains as shown below:
(i) Grass→ Grasshopper→ Hawk.
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(ii) Grass→ Grasshopper →Lizard →Hawk
(iii) Grass→ Rabbit→ Hawk
(iv) Grass→ Mouse→ Hawk
(v) Grass Mouse→ Snake→ Hawk
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(vi) Grass→ Insect→ Frog→ Snake→ Hawk