Lizards belong to the reptilia class and there are over 5600 species. They can be found on all continents except Antartica so they are a widespread group of the animal kingdom.
Lizards come in all shapes and sizes but one thing they generally have in common is that they have external ears and legs. I know that I was always taught that this is one way of distinguishing a lizard from a snake, but there are legless lizards, so this is not always accurate. Lizards, such as geckos, can be only a few centimenters long whereas large lizards, like the Komodo dragon can grow to be almost 3 meters long.