Vertebrates are animals which have a vertebral column or a notochord at any point in their lives.
They  are classified into 7 classes based on their anatomical and physiological features:
1. Mammals (Class Mammalia) - They  have the ability to regulate their body temperature irrespective of the surrounding temperature. Thus they are endothermic. Example - humans and platypuses.
2. Birds (Class Aves) - they are characterised by feathers, toothless beaks and a higher metabolic rate. They lay hard-shelled eggs. example - Crow, Pigeon
3. Reptiles (Class Reptilia) - Examples in this class are snakes, crocodiles and turtles. Characteristically they are ectothermic.
4. Amphibians (Class Amphibia) - Examples in this class are frogs toads and salamanders. They are ectothermic. Both reptiles and amphibians are considered tetrapods, but the distinguishing feature between them is their breeding behaviour. Amphibians need water to breed and their eggs are shell-less. They also undergo metamorphosis where the young ones change from aquatic larval form (having gills and fins) to terrestrial adult form.
5. Bony fishes (Class Osteichthyes) - They are characterized by their bony skeleton. They are the largest class of vertebrates . example - Siamese fighting fish
6. Cartilaginous fishes (Class Chondrichthyes) - They have cartilaginous skeleton. Example - sharks, rays, skates and sawfish.
5. Jawless fishes (Class Agnatha) - They are primitive fishes having a jawless, circular mouth  which help in holding and feeding on other fishes. They are mostly parasites and scavengers. Example - hagfish