Worms serve varying purposes in nature, depending on the species. For example, silk worms provide a fine silk while earthworms enrich compost piles to make healthy soil. Some worm species feast on the dead flesh of animals, helping them to further decompose. This is all part of nature's chain -- the worm population is able to thrive as a result of the death of another creature.
Flatworms are predators that decompose dead animal matter and sometimes even feed on live, injured animals. This type of worm can stretch its mouth to suck the juices from its prey, which can even include other worms in its species. These worms have triangle heads and crawl along the bottoms of lakes, rivers, streams and just about anywhere else there is water. They leave a trail of mucus in their paths and can glide along the surface of the water and up and down plants.
In addition to helping to decompose food and plant matter, earthworms also help dead animals to decompose. These worms take the nutrients from the animal and return them to the earth through the soil that is enriched from their excrement, or castings. These worms can be found just about anywhere and provide an important link in nature's food chain. Without species like earthworms that help to decompose living organisms, future organisms would fail to thrive.
Red worms, like other species of worms, live off of the ability to decompose dead animals and other organic matter. This species is also preferable for composting and has a short life span of just a year. It uses its gizzard to break down anything it consumes and is a hermaphrodite, like most other worm species. They thrive in moist conditions, and require oxygen to survive.
When given the opportunity, nematodes willingly participate in the decomposition process of animals or vegetation. Since they generally live on the sea floor or in other waterways, they don't always get to feed in this manner and must sometimes attach themselves to a live host. They tend to travel in abundance. One rotted apple can contain up to 90,000 nematodes furthering the decomposition process of the fruit, according to Cornell University.