Vertebrates vs Chordates
Vertebrates are the major group of the chordates in terms of the number of species, evolutionary sophistication, and many other aspects, as well. As a large portion of people believes that chordates are the same as vertebrates, the existing difference between the groups should be laid out in a common ground, so that the distinction should be obvious. This article would be such a common ground with information on both vertebrates and chordates being presented and compared.
Vertebrate animals have their unique backbone with the spinal cord. The backbone is a column of vertebrae, which are parts of their internal skeleton. The skeleton could be either bony or cartilaginous. Among members of the chordates, they are the largest group including Birds, Mammals, Fish, Amphibians, and Reptiles. Their spinal cord runs along the body between cranial and caudal regions through the hollow tube of the backbone. The vertebrates have a bilaterally symmetrical bodies. The most important feature of the vertebrates is the well-developed brain covered by the bony structure called skull. Their respiratory systems function with either lungs or gills for gas exchange between the animal and the environment. Sometimes, there are other gas exchanging surfaces viz. oral cavities and skins have been important, especially in amphibians. The vertebrate digestive system is a complete one starting at the mouth and ends after rectum. This gastro intestinal tract lies ventrally to the spinal cord. Additionally, the mouth opens from the anterior and the anus opens from the posterior end of the body. The circulatory system is a closed one with a ventrally located heart. Those are the major characteristics of vertebrates.
Chordates are primarily the animals with some very distinctive characteristics including a notochord, dorsal nerve chord, pharyngeal slits, endostyle, and a muscular tail. The vast majority of the chordates have a well-organized internal skeleton system made up of either from bones or cartilages. However, there are some variations, accepting the rule that there is always an exception. The Phylum: Chordata includes more than 60,000 species with over 57,000 vertebrate species, 3,000 tunicate species, and few lancelets. Vertebrates include fish, amphibians, reptiles, birds, and mammals while larvaceans and salps included in the tunicates. However, all these animal groups possess the features mentioned in the definition. The notochord is an internal structure that is very hard in nature, and it develops into the backbone of the vertebrates. The extension of the notochord makes the tail in chordates. The dorsal nerve chord is another unique feature of the chordates, and it is the spinal cord of vertebrates in popular tongue. Pharyngeal slits are a series of openings found immediately posterior to the mouth, and these may or may not last forever during the lifetime. That means these pharyngeal openings occur at least once in any vertebrate’s lifetime. The endostyle is an internal groove found in the ventral wall of the pharynx. The presence of these features characterizes any animal as a chordate.
What is the difference between Vertebrates and Chordates?
• All the vertebrates are chordates, but not all the chordates are vertebrates.
• Diversity is exceptionally higher among vertebrates than among the non-vertebrate chordates.
• The clear cephalization is much pronounced in vertebrates than in non-vertebrate chordates.
• The muscles are arranged in paired masses among all the vertebrates but not in all chordates.
• Vertebrates do have a spinal cord and backbone but not the other chordates.