The Animal Kingdom
A look at the different species
A mammal is classified as a warm-blooded vertebrate animal that is distinguished by the possession of hair or fur, the secretion of milk by females for the nourishment of the young, and (normally) the birth of live young. Mammals are not limited to terrestrial life, they are also found in aquatic ecosystems.
Birds are classified as being warm-blooded egg-laying vertebrates that are in the possession of feathers, wings and beaks. Though all birds have wings not all are capable of flight, some have adapted to running on land while others have evolved to be able to swim.
Amphibians are cold-blooded vertebrates that are unique in a way that they change from an aquatic gill-breathing larval stage and as they mature go to a terrestrial lung-breathing adult.
Life cycle of a Frog!