Basis of Classification
Species is the basic unit of classification. Organisms that share many features in common and can breed with each other and produce fertile offspring are members of the same species. Related species are grouped into a genus (plural- genera). Genera are grouped into families; related families into orders; related orders into a class; related classes into a phylum (plural -phyla); and related phyla into a kingdom.
Kingdoms are very large groups, embracing millions of kinds of organisms. Most biologists recognize different kingdoms (although other schemes of classification exist). All animal groups belong to the Animal Kingdom and likewise plants to the Plant Kingdom