Anélidos

Anélidos, commonly known as segmented worms, represent a large phylum of invertebrate animals. Their most distinctive characteristic is the segmentation of their bodies into a series of repeating units, both externally and internally. This segmentation allows for greater flexibility and specialized functions within different body regions. Anélidos are bilaterally symmetrical and possess a true coelom, a fluid-filled body cavity that supports internal organs.

This phylum includes a diverse range of species, such as earthworms, leeches, and marine worms. They inhabit a variety of environments, from freshwater and marine ecosystems to terrestrial soils. Anélidos play crucial roles in their respective habitats, often acting as decomposers, bioturbators, or as food sources for other animals.

Their circulatory system is typically closed, meaning blood is contained within vessels. Respiration can occur through the skin (cutaneous respiration), gills, or specialized structures. Anélidos exhibit a range of feeding strategies, from filter-feeding and deposit-feeding to predation. Reproduction is varied, with some species reproducing sexually, others asexually, and some exhibiting both modes. The study of Anélidos falls under the branch of zoology known as annelidology.