Segmented worms get their food from dead plants and animals. They ingest soil that contains decaying organic material, and their excreted waste provides nutrients for plants.
Segmented worms play a very important role in the ecosystem as they help to dispose of decaying matter and turn it into fertilizer. Their excretion is called casts and is very high in nutrients like nitrogen, phosphorus and potash. Plants cannot use decaying matter directly, so these casts are a very important food. Segmented worms also dig tunnels in the ground while eating, which aerates the soil.
Worms have a mouth at one end of their body and an anus at the other. They do not have eyes but possess the ability to detect light by light-sensitive skin on their head. Segmented worms have 100 to 150 segments with each segment housing a portion of the digestive system. Segmented worms do not have lungs; they breathe through their skin by diffusion of oxygen and carbon dioxide. Living in damp soil is crucial for survival as moist skin is needed for diffusion to occur. The segments of the worm's body also provide mobility by containing muscles. As one segment's muscle contracts, another relaxes so that the worm is able to inch forward, and bristle-like setae on the outside help give traction.