Groups of Annelids The groups of annelids are Oligochaeta, Hirudinea,and Polychaetes. Oligochaetes include earthworms and their relatives, Hirudinea includes leeches, and Polychaetes include sandworms, bloodworms, and their relatives. chaetes have relatively streamlined bodies unlike Polychaetes. Hirudineas eat worms but Oligochaetes eat dirt. Polychaetes live in cracks inside of coral reefs while Hirudinea live in moist habitats on land.
Ecology of Annelids Annelids recycle two meters or more of soil by mixing it to depth, aerating, and burrowing soil for their entire life. Their pathways help plant s and allow water and oxygen for the plants to grow and for the growth of oxygen-requiring soil bacteria. Moles and birds have a diet consisted of orms. The waste earthworms produce are rich in nutrients and nitrogen, benefiting the soil with good bacteria. Marine annelids have free swimming larvae and when they are older, they become mud-dwelling filter feeders. They are important for crustaceans and fish since worms are a part of their diet.