Segmented worms (phylum Annelida) have elongated, cylindrical bodies that are segmented or divided by grooves, both internally and externally. There are so many segmented worm species burrowing through the earth, it would be nearly impossible to list them all here. At last count, there were more than 9,000 species of segmented worms on the planet today. Some of the most common types of segmented worms include earthworms, leeches, and sandworms. Earthworms make up the largest and most diverse group of segmented worms in the world. In all, there are more 2,700 different types of earthworms living in every corner of the earth today.
Earthworms, like all segmented worms, can be found all over the world. They live in trees, in bark, and under rocks as well as along rivers and near springs, and ponds. Their favorite place to live, however, is in the earth’s rich soil. During the winter months, they burrow deep within the earth until the surface warms again during the spring. During the warm summer months, worms stay closer to the tops of soil where they create tunnels to wiggle in and out of. These tunnels are extremely important for plant life as they create a path for water and air, which is essential for the survival of plant life.
Places like China, Australia, Greenland, and the Sahara Desert have their own indigenous species of worms. Besides the Sahara Desert, you won’t find large numbers of worms living in “sandy” areas, especially sandy beaches. The vast majority of worms on our planet can only survive under certain environmental conditions.
Worms have no lungs, so they breathe through their skin. This means that the worm’s environment and skin must be moist at all times. This allows the worm to breathe in oxygen. If the worm’s skin dries out, the worm will die from suffocation. While worms need moisture to survive, too much moisture can be fatal. If too much water is present, it takes the place of oxygen, which will cause the worms to flee to the surface. Once on the surface, worms will be exposed to sunlight. If worms remain in the sunlight for too long, they can become paralyzed.
In addition to needing a moist environment for survival, worms must also remain close to their food supply. Worms feed off leaves and dead grass, which contain organisms that provide a healthy diet of bacteria, algae, and fungi. Worms feast on dirt as well, especially if they live deeper inside the earth. Worms also eat plants, fruits, and vegetables.
Although you cannot see them, unbelievably, worms do have mouths. The worm’s mouth is actually big enough and powerful enough to grab a leaf and drag it around. They also have a pharynx, esophagus, crop, gizzard, and intestine. When the worm eats its food, it pulls the materials into its mouth with the help of the pharynx and its prostomium (also called acron). This creates a suction motion. This suction motion aids in helping the worm consume large amounts of food in a sort amount of time. The gizzard grinds the food. Worms eat so much that they typically produce excrement equal to their own weight every 24 hours.
The worm’s moist, sustenance rich environment plays an extremely important role in reproduction as well. Worms prefer to mate and reproduce in warm moist soil, preferable, away from the light.