Define and understand the following terms: (i) Phylum (ii) Class (iii) Family (iv) Order (v) Genus

**(i) Phylum**
* Phylum is a **higher taxonomic category** than Class.
* Classes comprising animals like fishes, amphibians, reptiles, birds along with mammals constitute the next higher category called **Phylum**.
* All these animals within a phylum share common features, such as the presence of **notochord and dorsal hollow neural system**, and are included in a phylum like Chordata.
* In the case of plants, classes with a few similar characters are assigned to a higher category called **Division**, which is the equivalent rank to Phylum in animal classification.
* All animals belonging to various phyla are assigned to the highest category called Kingdom Animalia.
* Phylum is one of the common taxonomic categories developed from taxonomical studies of known organisms.

**(ii) Class**
* Class is a taxonomic category that **includes related orders**.
* It is a **higher category** than Order and lower than Phylum/Division.
* For example, the order Primata, which comprises monkey, gorilla, and gibbon, is placed in the class **Mammalia** along with the order Carnivora, which includes animals like tiger, cat, and dog. Class Mammalia includes other orders as well.
* Class is one of the common taxonomic categories in the taxonomic hierarchy.
* Classes with a few similar characters in plants are assigned to a higher category called Division.

**(iii) Family**
* Family is the next category after Genus in the taxonomic hierarchy.
* It contains a group of **related genera**.
* Genera within a family have a **still less number of similarities** compared to species within a genus.
* Families are characterised on the basis of both **vegetative and reproductive features** in plant species.
* For example, in plants, three different genera *Solanum*, *Petunia*, and *Datura* are placed in the family **Solanaceae**.
* Among animals, the genus *Panthera* (comprising lion, tiger, leopard) is put along with the genus *Felis* (cats) in the family **Felidae**. Cat and dog, while showing some similarities and differences, are separated into two different families: Felidae and Canidae, respectively.
* Family is one of the common taxonomic categories in the taxonomic hierarchy.

**(iv) Order**
* Order is a taxonomic category that is **higher than Family** and **lower than Class**.
* Orders and other higher taxonomic categories are generally identified based on the **aggregates of characters**.
* An Order is an **assemblage of families** which exhibit a few similar characters. The similar characters are less in number compared to different genera included in a family.
* For instance, plant families like Convolvulaceae and Solanaceae are included in the order **Polymoniales**, mainly based on their floral characters.
* The animal order **Carnivora** includes families like Felidae and Canidae.
* Order is one of the common taxonomic categories in the taxonomic hierarchy.

**(v) Genus**
* Genus is a taxonomic category that is **higher than Species** and **lower than Family**.
* It comprises a **group of related species** which have more characters in common compared to species of other genera.
* Genera are considered **aggregates of closely related species**.
* For example, potato (*Solanum tuberosum*) and brinjal (*Solanum melongena*) are two different species that belong to the genus **Solanum**.
* Lion (*Panthera leo*), leopard (*Panthera pardus*), and tiger (*Panthera tigris*) are all species of the genus **Panthera**, sharing several common features.
* The genus *Panthera* differs from another genus, *Felis*, which includes cats.
* In binomial nomenclature, the **first word** in the scientific name represents the genus. It starts with a capital letter. When handwritten, it is separately underlined, or printed in italics, to indicate its Latin origin.
* Each genus may have one or more specific epithets representing different organisms, but having morphological similarities.
* Genus is one of the common taxonomic categories in the taxonomic hierarchy.