An ecosystem comprises the physical environment.
It is an interlinked system with the plants and animals living therein linked to each other.
Ecosystems have evolved over a period of thousands of years.
Some examples of interlinking are
(i) Insects help in pollination of crops and fruit trees. Some insects also exert biological control on harmful insects.
(ii) Carnivorous animals kill herbivorous animals for food and herbivorous animals consume plants for food.
(iii) Decomposers like fungi and bacteria fertilise the soil with humus by decomposing dead animals and plants to enable plants to grow. There are many such examples of interlinking to show that every species has a role to play in the ecosystem.
Thus, we can conclude that every species has a role to play in the ecosystem.