Polychaeta

Polychaeta are a class of segmented worms commonly found in marine environments. They have a soft, often elongated body divided into many segments, each with tiny bristles called chaetae that help in movement and interaction with their surroundings. Polychaetes exhibit a wide variety of forms and lifestyles, including burrowers, free swimmers, and tube-dwellers. They play important roles in ocean ecosystems by aerating the sediment, recycling nutrients, and serving as food for many marine animals. Despite their diversity, all polychaetes share features like segmented bodies and parapodia—paired, fleshy appendages used for movement and respiration.