Download Vertebrates | Definition, Characteristics & Classifications and more Study notes Biology in PDF only on Docsity! Vertebrates | Definition, Characteristics & Classifications A vertebrate is an animal with a backbone. They differ from invertebrates, which are animals without backbones. Fish, birds, amphibians, reptiles, and mammals are all examples of vertebrate animals. Classification of vertebrates Vertebrates are a group of animals found in Kingdom Animalia. They are in the Phylum Chordata. They are in the subphylum Vertebrata. There are seven classes within this subphylum. The classes of vertebrates include Agnatha (jawless fish), Chondrichthyes (cartilaginous fish), Osteichthyes (bony fish), Amphibia (amphibians), Reptilia (reptiles), Aves (birds), and Mammalia (mammals). Characteristics of Vertebrates Vertebrates possess a backbone through the length of the animal, either in the form of a vertebral column or a notochord. In the case of human beings, the notochord which is present during embryonic life develops into a vertebral column at a later stage. Another striking feature of vertebrates is the presence of the spinal cord and gastrointestinal tract. Within the vertebral column, there is a spinal cord through which groups of nerves arise, which expands to the brain and different parts of the body. The mouth is present at the anterior portion of the alimentary canal and ends at the anus that opens to the exterior. Most vertebrates have a tail at the end of the anus. Vertebrates also possess paired appendages in the form of fins or limbs. Vertebrates have a ventral muscular heart with either two or three, or four chambers. 5 Groups of Vertebrates The five main groups of vertebrates are fish, amphibians, reptiles, birds, and mammals. There are actually more categories, since bony fish are separate from jawless fish (lampreys and hagfish), cartilaginous fish (sharks and rays), and lobe-fin fish (lungfish and coelacanths). Agnatha (Jawless Fish) Chondrichthyes (Cartilaginous Fish) Sarcopterygii (Lobe-Finned Fish) Osteichthyes (Bony Fish) Amphibia (Amphibians) Reptilia (Reptiles) Aves (Birds) Mammalia (Mammals) Mammals: The chief highlights of the vertebrates of this class are: Found in a variety of habitats Four Chambered heart Warm-blooded Ability to regulate their body temperature and are called endothermic animals. Mammary glands are present to feed younger offspring. Presence of two pairs of limbs, external ears/ pinnae, teeth, Hairy skin Sexes are separate, and fertilization is internal. Generally, they give birth to offsprings, i.e. viviparous, with exceptions like Platypus. Examples: Kangaroo, Lion, Tiger, Cat, Dog etc
