Annelida (Segmented Worms)

Family: Annelida
Annelida is a phylum comprised of segmented worms. Segmented or  segmentation  means to the division of an organism's body plans into a series of repetitive or identical segments. This is why these worms are also called ringworms. Annelids survive by living in aquatic habitats or as burrowers in damp soil.

Polychaeta
These are marine annelids, who live in the oceans and seas of the world. However, they're not the typical pink worms you see on the muddy ground. In other words, Polychaeta are tube worms. They are brightly colored and have many bristles. Most live to the Earth's deepest depths, where hydrothermal vents and underwater volcanoes have been discovered. In order to survive the harsh climates, these worms live inside their worm tube. To collect food, the plumes collects oxygen, hydrogen sulfide and carbon dioxide from the water. Bacteria convert these molecules into carbohydrates (sugar), which tube worms use as a source of food and energy. Other worms who live close to the water's surface are crawling along the bottom, burrowing, free swimming, tube-dwelling or boring, commensalism, and parasitism.

Oligochaetathe
These are one of the most worms you see everyday. These kinds of worms can live in marine & freshwater habitats. This also include terrestrial (Earth) worms, such as the common earthworm. Despite worms don't have the necessary traits if they're aquatic or terrestrial, worms can breathe through their skin in water and air. In order to feed themselves, they can either feed on bacteria, fungus, and protozoan on the ground, decaying leaves and roots in the ground, microorganisms floating in the water, or eat the decomposing remains of a dying organism.

Hirudinea
Hirudinea are a class of leeches. They have a long body like the Oligochaetathe, but rather than having a small mouth with no teeth, they have a circular mouth shape with razor-shaped teeth for attaching and sucking nutrients from their host. Leeches are most definitely parasitic organisms, feeding on the prey and nutrients from another organism while their host weakens. This is called a parasitic relationship.