It might seem quite astonishing to you but it is true that each living creature (including human beings) belongs to the most complex food web.
Food web consists of different number of food chains. A food chain provides us the hierarchy of organisms on the basis of the food they consume.
It commences with – producers, proceeds with primary, secondary and tertiary consumers.
Producers are the green plants, i.e., the autotrophs that produce food through photosynthesis.
Primary consumers are the one that consume the producers. Such plant eating animals are known as herbivores.
Secondary consumers are the ones that consume the animals or primary consumers. They can be carnivores – surviving only on animal flesh (meat eaters) or omnivores – can eat both, flesh and plants.
Extinction of any of the consumers or producers will severely affect the food chain and can lead to the extinction of life on earth.
As carnivores depend on the herbivores for their survival. With the extinction of herbivores they will start hunting other carnivores and a competition of food and struggle for existence will begin. This can lead the entire food chain to die.
With the extinction of producers, no organism can survive as the producers or plants are the only source of oxygen on earth. Moreover, herbivores depend on them for their survival. With their extinction, the herbivores will die leading to the extinction of carnivores and the entire food chain.
Thus, each organism is necessary for the survival of the other organism in the food chain.