Taxonomy is the system used to classify orgainisms into groups and the system of naming is called nomenclature.
Orgainisms are put into groups based on the largest number of common characteristics. They are firstly divided into one of five large groups called the kingdom. The kingdoms are, in increasing complexity:
Each kingdom can be subdivided into progressivly smaller and smaller groups, leading to an individual species. These groups are known as the hierarchial levels and there are 7 of them, their order (along with an example, humans) are:
Kingdom - Animalia