Home > Tunicate

Urochordata (sometimes known as tunicata and commonly called urochordates, tunicates or sea squirts) is the subphylum of saclike filter feeders with input and output siphons. They are members of the phylum Chordata, which also includes birds, fish, and mammals. As with other chordates, tunicates possess a notochord during their early stages of development. Larval stages may have the appearance of a tadpoleA tadpole (also known as a pollywog is a larval frog, toad, salamander, or newt. In this stage it breathes by means of external or internal gills, is at first lacking legs, and has a finlike tail. As a tadpole matures, it metamorphoses by gradually growin, whereas the adult stage has a much more barrel-like shape. They feed by filtering sea water through a gillGill In aquatic organisms In aquatic organisms, gills are a respiratory organ for the extraction of oxygen from water and for the excretion of carbon dioxide. Many small aquatic animals absorb oxygen through the surface of their bodies in general, but mor basket.

Tunicates consist of two openings in their body cavity. There consists an incurrent as well as excurrent siphon. The incurrent siphon is used for food and water to enter in and the excurrent siphon allows for water as well as waste to pass through and exit the tunicate. The main source of food that the tunicate consumes is planktonPlankton is the aggregate community of weakly swimming but mostly drifting small organisms that inhabit the water column of the ocean, seas, and bodies of freshwater. The name comes from the Greek term, —meaning "wanderer" or "drifter". While some forms o. Plankton gets entangled in the mucus secreted from the endostyle . The tunicate's pharynxThe pharynx is the part of the digestive system of many animals immediately behind the mouth and in front of the esophagus. In mammals, it is where the digestive tract and the respiratory tract cross, commonly called the "throat" (which term may also incl is covered by miniature hairs called ciliated cell s which allow the consumed plankton to pass down through to the esophagusThe esophagus oe/oesophagus , or gullet is the muscular tube in vertebrates through which ingested food passes from the mouth area to the stomach. Food is passed through the esophagus by using the process of peristalsis. Specifically, in mammals, it conne.

Some larval forms appear very much like primitive chordateSubphylum Urochordata Tunicates Ascidiacea Thaliacea Larvacea Subphylum Cephalochordata Lancelets Subphylum Myxini Hagfishes Subphylum Vertebrata Vertebrates Petromyzontida Lampreys Placodermi extinct Chondrichthyes Cartilaginous fishes Acanthodii extincts or hemichordates with a notochord (primitive spinal cordThe spinal cord is a part of the vertebrate nervous system that is enclosed in and protected by the vertebral column (it passes through the spinal canal). It consists of nerve cells. The cord conveys the 31 spinal nerve pairs of the peripheral nervous sys). Some forms have a calcereous spicule that may be preserved as a fossil. Jurassic to Present with one proposed Neoproterozoic form - Yarnemia.

Once grown, adults can develop a covering to protect themselves from enemies.

Tunicate blood is particularly interesting. Unlike some blood that contains iron or copper, tunicate blood stores oxygen in the rare metal vanadium, which it draws from the water. It is still unknown how they do this.