The classification of all living organism has been done by dividing them into different levels based on their features and characteristics. There is a hierarchy in this classification and each step represents a rank or category known as taxonomic category. There are around seven main taxonomic ranks or categories - species, genus, family, order, class, phylum/division and kingdom. Group of individuals having similar fundamental qualities are called species. When the group of related species have more common characters among them they are referred to as genus. Families which exhibit few similar characters are placed under the same Order. All the fishes, amphibians, reptiles, birds along with mammals constitute the taxonomic level phylum.