What is the literal meaning of Urochordata?
Definition of Urochordata : a subphylum or other division of Chordata comprising the tunicates and including the classes Ascidiacea, Thaliacea, and Larvacea.
Why Urochordates are called?
Urochordates are called tunicates because of the leathery covering or tunic. It provides protection.
What does the name tunicate signify?
having a tunic or mantle. : Also ˈtuniˌcated (ˈtunɪˌkeɪtɪd ; ˈtjunɪˌkeɪtɪd ) noun. 3. any of a subphylum (Tunicata) of solitary or colonial sea chordates, having a saclike body enclosed by a thick tunic, including the salps and ascidians.
What is unique about Urochordata?
The tunicates (urochordates) are the only animals known to produce highly crystalline cellulose1. The name “Tunicata” is derived from the unique integumentary tissue called the “tunic”, which contains the cellulose microfibrils.
How do Urochordata and Cephalochordata differ?
The main difference between Urochordata and Cephalochordata is the location and presence of notochord. In urochordates, the notochord is present in the larval tail, whereas, in cephalochordates, the notochord is present throughout the life and extends from the head to the tail region.
What do Cephalochordates and Urochordates have in common?
Similarities Between Urochordata and Cephalochordata Both Urochordata and Cephalochordata consist of pharyngeal gill slits, a notochord, a dorsal, hollow, nerve cord, and a post-anal tail. Both Urochordata and Cephalochordata lack well-developed sensory organs.
Why Urochordata and Cephalochordata are called Protochordates?
They are the most primitive chordate animals. They are also known as Protochordates since they do not possess a well developed spinal cord and they possess a primitive nerve chord instead, they are also known as lower Chordata.
What class do tunicates belong to?
Some tunicates live as solitary individuals, but others replicate by budding and become colonies, each unit being known as a zooid….Tunicate.
| Tunicates Temporal range: [tentative] | |
|---|---|
| Phylum: | Chordata |
| Clade: | Olfactores |
| Subphylum: | Tunicata Lamarck, 1816 |
| Classes and unplaced genera |
Who are Protochordates?
Protochordates are an informal category of animals (i.e.: not a proper taxonomic group), named mainly for convenience to describe invertebrate animals that are closely related to vertebrates. These animals have pharyngeal gill slits and a dorsal nerve cord, which is usually solid.
What is the relationship between the term notochord in Urochordata?
The 1,300 species of urochordates, like all members of the phylum Chordata, possess four characteristic anatomical structures as embryos: a flexible body-length rod (the notochord ) that provides resistance against muscular contractions and allows for more efficient movement; a dorsal , hollow, nerve cord that forms …
How do urochordates reproduce?
Tunicates are generally hermaphrodites that sexually reproduce by cross-fertilization. That means that an individual does not use its own sperm to fertilize its eggs. Instead, they obtain sperm released into the open ocean by other individuals. Fertilization is usually internal.
What is the difference between Hemichordata and Urochordata?
In urochordates, the dorsal tubular nerve cord is present in the larval form and degenerates in the form of small ganglion in the adult. Hemichordates, on the other hand, lack notochord and true dorsal nerve cord.
Why is it called Urochordata?
The name Urochordata is derived from the fact that the notochord is present in the tail (from the ancient Greek uron, tail). Tunicates or Urochordates are the closest relatives of vertebrates. They are marine filter-feeding animals, found at all the latitudes, and can assume a planktonic or benthic lifestyle.
Why Urochordata is called ascidian tadpole?
Elongated larva of Urochordata is known as ascidian tadpole larva. Adult emerges from the larva by the process of metamorphosis. 2. Notochord restricted at the caudal end, hence name Urochordata.
What is the urochordate subphylum?
The urochordate subphylum includes the ascidians, the thaliaceans, and the appendicularians. Nearly all ascidians, some thaliaceans, and all appendicularians have a free-swimming larval stage with a notochord and a small central nervous system that appear homologous to the same structures in craniates.
What is Cephalochordata?
Any of the primitive fishlike creatures, of the subphylum Cephalochordata, including the lancelets, that lack a true spine but have a notochord which, in the case of cephalochordates, reaches into the head, contrary to the Urochordata.