Question

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

Answer 1

(i) Phylum: ​

1. The phylum comes right after the kingdom and this is the first step towards the specificity of characters.
   
2. There is a difference in rank names for the plant and animal kingdoms. A phylum under the plant kingdom is called Division whereas in animals it is referred to as phylum only.
   
3. When we consider the animal kingdom as an example we can see organisms with or without notochord being separated. We also see in the case of the plant kingdom that the different groups are based on the different habitats the plants live in. e.g. Chordata, Magnoliophyta.

(ii) Class

1. Class is a rank below the phylum or division in the hierarchy of classification.
   
2. The class is a taxonomic group consisting of one or more related orders. For example, the class, Mammalia, includes many orders like Primata (Man), Carnivora (tiger), etc.

(iii) Family

1. A family is comprised of one or multiple related genera.
2. eg., Family Hominidae contains apes, monkeys, and man.
3. In plants, families are categorized on the basis of vegetative and reproductive features.

(iv) Order

1. Order is the assemblage of multiple families within it.
2. Families such as Canidae(Dogs, Wolves, Jackals) and Felidae(Leopard, Tiger, Jaguar) are included under the order Carnivora, i.e. flesh consuming animals or animals that eat other animals for nutrition.

(v) Genus

1. Genus is comprised of one or more related species.
2. There are characteristics that correlate with the species falling in a certain genus.
3. We often see species that resemble a lot to one another and are differentiated just by a few key features.
4. There can be one species belonging to a certain genus which is known as the Monotypic genus. e.g. Breonadia salicina is the only species for the genus Breonadia.
5. There can also be multiple species belonging to a certain genus which is known as the Polytypic genus. e.g. Solanum tuberosum, Solanum lycopersicum, and many more belong to the genus Solanaceae.