Vertebrates are animals that have a vertebral column and/or a notochord at some point in their lives and are classified as such.The presence or absence of the vertebrate is one of the ways in which life can be classified, and this is one of the classifications used. Both vertebrates and invertebrates descended from a common ancestor that lived approximately 600 million years ago, according to current scientific theory.It was 525 million years ago that the first evidence of true vertebrates was discovered. Since then, vertebrates have diverged into a long lineage that includes everything from armoured fish and giant sauropods to woolly mammoths and modern man.
Characteristics of Vertebrates
In biology, a vertebrate is defined as an animal that has all of the following characteristics at some point in its lifetime:
- A stiff rod running the length of the animal (it could be the vertebral column and/or notochord, depending on the species).
- All vertebrates, including humans and all other vertebrates, are born with a notochord, which eventually develops into the vertebral column.
- The alimentary canal is located below the vertebral column and is connected to it by a bundle of nerves (the spinal cord).
- The mouth of the animal is located at the anterior portion of the animal’s body or directly below it.
- The alimentary canal comes to a close at the anus, which is the opening to the outside world. The tail is a continuation of the anus.
Classification of Vertebrates
Vertebrates are divided into seven groups based on the anatomical and physiological characteristics of their bodies. They are as follows:
Mammals (Class Mammalia)
Organisms belonging to this class have the ability to regulate their body temperature regardless of the temperature of their surrounding environment. As a result, mammals are referred to as endothermic animals, which includes humans and platypuses among others.
Birds (Class Aves)
Birds are dinosaurs, at least from a biological standpoint (more aptly called avian dinosaurs). feathers, toothless beaks, and a rapid metabolic rate distinguish this group of organisms from the rest of the animal kingdom. Furthermore, members of the Aves class lay eggs with a hard shell.
Reptiles (Class Reptilia)
Snakes, crocodiles, tuataras, and turtles are examples of tetrapods, which include a variety of other tetrapods. Reptiles are characterised by the fact that they are ectothermic in their natural environment. Snakes are still classified as tetrapods, despite the fact that they have no visible limbs. This is due to the fact that snakes descended from ancestors who had limbs, as previously stated.
Amphibians (Class Amphibia)
Amphibians are ectothermic tetrapods that include frogs, toads, and salamanders, among others. The breeding behaviour of amphibians distinguishes them from reptiles and serves as a distinguishing characteristic. Because their eggs are shell less, most amphibians require a body of water in order to reproduce. Furthermore, they go through a process known as metamorphosis, in which the young ones transform from a fully-aquatic larval form (complete with gills and fins) to a fully-aquatic adult form.
Bony fishes (Class Osteichthyes)
The skeleton of this group of fishes is primarily composed of bone rather than cartilage, which distinguishes them from other fishes (such as sharks). Osteichthyes is the largest class of vertebrates on the planet today, and it is also the oldest.
Cartilaginous fishes (Class Chondrichthyes)
As the name implies, the cartilaginous skeleton is what distinguishes this class of organisms. Sharks, rays, skates, and sawfish are among the group’s members. A few sharks, such as the massive Greenland shark, can live for hundreds of years or even decades. In 2016, a specimen with a transmission medium was discovered to be at least 273 years old.
Jawless fishes (Class Agnatha)
There have been no significant changes in these very primitive fishes since they were discovered in fossil records millions of years ago. In addition to having a circular mouth with no jaws, they also have rows of small sharp teeth that help them hold and feed on other fish. The majority of the members of this class are parasites or scavengers in nature.
Conclusion:
People are considered vertebrates, which are animals with skeletons and backbones, and they are classified as such. There are many different kinds of vertebrates that can be classified into a variety of different groups, each with its own set of characteristics. Humans, mammals, birds, amphibians, reptiles, and fish are just a few examples of the types of creatures that fit this description.Before moving on to the characteristics of vertebrates, it is important to note that the class Vertebrata is a subclass of the phylum Chordata. Besides these, there are two other sub-phyla that exist: Cephalochordata and Urochordata.