Stand under this big tree and pick up a twig. Dig lightly in the soil under the tree. We can see decayed leaves, twigs, and flowers piled loosely in the soil. As we continue to dig, we find millions of insects and other tiny creatures living there together with plants. Their excrement and their carcasses combine with fallen leaves, decaying and enriching the soil.
Leaves fall and decay.
Twigs of trees are broken off by a strong wind. The trunks of trees are blown down and lie on the earth. Gradually, animals and plants begin to eat this organic matter. In due time, these tiny animals and plants also die and decay, and they become part of the soil, along with other organic wastes. Soon earthworms and ants eat these piles of rotting matter and they themselves return to the earth.