Tunicata

Tunicata, commonly known as tunicates or sea squirts, are marine animals belonging to the phylum Chordata, which also includes vertebrates like fish and humans. They have a sac-like body encased in a tough tunic made of a cellulose-like substance. Tunicates filter seawater through their bodies to extract microscopic plankton and nutrients for food. They often attach to rocks, shells, or other surfaces in the ocean. Despite their simple adult form, tunicates share important features with vertebrates, such as a notochord in early development, making them valuable for studying evolutionary relationships among animals.