The document summarizes the key characteristics used to classify vertebrate animals into five groups: mammals, birds, reptiles, amphibians, and fish. It outlines where each group lives, how they have offspring, how they move, how they breathe, and their skin type/covering. Mammals are distinguished from reptiles by being viviparous and having fur/hair. Birds are distinguished from fish by living on land, using wings to move, breathing with lungs, and having feathers. The document aims to teach the differences between vertebrate classification groups.