What are 5 divisions of vertebrates?

The five divisions of vertebrates are fish, amphibians, reptiles, birds, and mammals. Fish are characterized by gills and fins, amphibians typically have a dual life stage (aquatic larvae and terrestrial adults), reptiles are known for their scaly skin and egg-laying habits, birds are warm-blooded and have feathers, and mammals are distinguished by their ability to nurse young with milk and usually have fur or hair. Each division exhibits unique adaptations that enable them to thrive in diverse environments.