The key difference between vertebrates and chordates is that the vertebrates are a major subphylum of chordates that have a vertebral column while the chordates are highly evolved animals that possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail during some period of their life span.
Vertebrates are a major group of chordates regarding the number of species, evolutionary sophistication, and many other aspects, as well. Moreover, many people believe that chordates are the same as vertebrates. However, chordates include two more subphyla other than the vertebrates. They are subphylum Tunicata (or Urochordata) and subphylum Cephalochordata. Hence, not all chordates are vertebrates, but all vertebrates are chordates. Therefore, this article attempts to highlight the existing difference between vertebrates and chordates in detail.
CONTENTS
1. Overview and Key Difference
2. What are Vertebrates
3. What are Chordates
4. Similarities Between Vertebrates and Chordates
5. Side by Side Comparison – Vertebrates vs Chordates in Tabular Form
6. Summary
What are Vertebrates?
Vertebrate animals have their unique backbone with the spinal cord. Hence, their 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.
Likewise, vertebrates have bilaterally symmetrical bodies. The most important feature of the vertebrates is the well-developed brain covered by the bony structure called a 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 such as oral cavities and skins have been important, especially in amphibians.
Figure 01: Vertebrates
Moreover, the vertebrate digestive system is a complete one starting at the mouth and ends after rectum. This gastrointestinal 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.
What are Chordates?
Chordates are primarily the animals with some very distinctive characteristics including a notochord, dorsal nerve cord, 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 above in the definition. The notochord is an internal structure that is very hard in nature, and it develops into the backbone or vertebral column of the vertebrates. The extension of the notochord makes the tail in chordates.
Figure 02: Chordate
Moreover, 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 are the Similarities Between Vertebrates and Chordates?
- All vertebrates are chordates. Hence, they share a similar morphology and anatomy.
- They possess a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail during some period of their lifetime.
- Also, both vertebrates and chordates include birds, amphibians, reptiles, mammals and fish.
- They are highly evolved animals that belong to Kingdom Animalia.
- Moreover, they are deuterostomes.
- Furthermore, they have bilateral symmetrical bodies.
- Besides, both these animal types are coelomates.
What is the Difference Between Vertebrates and Chordates?
Vertebrates are a major group of chordates. They have a backbone. On the other hand, chordates are highly evolved animals of the kingdom Animalia. They have a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail during some period of their lifetime. Chordates other than vertebrates do not possess a vertebral column. This is the key difference between vertebrates and chordates.
Moreover, a further difference between vertebrates and chordates is that the vertebrates include birds, reptiles, mammals, fish and amphibians. On the other hand, chordates include vertebrates, lancelets and tunicates. Other than that, vertebrates possess limbs, jaws, brain and skull that are not present in invertebrate chordates. So, this is also a difference between vertebrates and chordates.
Summary – Vertebrates vs Chordates
Chordates belong to Kingdom Animalia. It is a big phylum that includes two invertebrate subphyla and one subphylum of vertebrates. Chordates have a notochord, a dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail during some period of their lifetime. On the other hand, vertebrates represent majority of the chordates. Vertebrates have a vertebral column. Furthermore, vertebrates have a brain and a skull. There are five main groups of vertebrates; birds, amphibians, reptiles, fish and mammals. This summarizes the difference between vertebrates and chordates.
Reference:
1. “Chordate.” Wikipedia, Wikimedia Foundation, 18 Jan. 2019. Available here
2. Jollie, Malcolm T. “Vertebrate.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 22 Nov. 2017. Available here
Image Courtesy:
1.”Vertebrates”By Christian JanskyLeistenkrokodil, J. Patrick FischerCasuaris, Thurner HofElephant, Trisha ShearsMola from U.S. National Oceanic and Atmospheric Administrationderivative work (CC BY-SA 3.0) via Commons Wikimedia
2.”Figure 29 01 04″By CNX OpenStax (CC BY 4.0) via Commons Wikimedia