Question

Define and explain the following terms:
(a)Phylum
(b)Class
(c)Family
(d)Order
(e)Genus

Answer 1

Hint: - Taxonomy is the scientific method of naming, defining, and classifying groups of living organisms and viruses based on their common characteristics. The terms given here are used in biological taxonomy. They are used to classify the living organisms on the planet based on their various similarities and differences.

Complete answer:
(a) Phylum - It is a level of classification or taxonomic rank below kingdom and above class. The Animalia or Metazoa kingdom contains approximately 35 phyla. The Plantae kingdom contains approx 14, and the Fungi kingdom contains approx 8 phyla. Examples include Chordata, Basidiomycota, Amoebozoa, Bryophyta, etc.
(b) Class - It is a taxonomic rank that fits between phylum and order. The organisms in one class share the characteristics of the phylum but have more advanced characteristics to distinguish them from each other. Examples of the class are Mammalia and Aves.
(c) Family - It is a taxonomic rank that fits between order and genus. It is generally subdivided into subfamilies. The classification of organisms into a family is not very strictly defined and is discussed thoroughly between taxonomists.
(d) Order - It is a taxonomic rank that fits between class and family. Some organisms are consistently grouped in a particular order by their suffixes. For example, ‘-formes’ is used for birds and fishes only.
(e) Genus - This taxonomic rank is used as the first part of the binomial species name in binomial nomenclature. It fits between family and species. It is a part of the scientific name or the generic name. For example, in the bacteria Escherichia coli, the genus is Escherichia.

Additional Information: Class is subdivided into superclass, class, subclass, infraclass, subterclass, and parvclass.
- For naming organisms in a family, the nomenclature of plants, algae, and fungi usually end with the suffix ‘-aceae’ while the family names of the animals end with ‘-idae’.
- A rank higher than order can be added as ‘superorder’, while that lower than order can be added as ‘suborder’.
- The plural of genus is genera.

Note:
 - While stating the scientific name of an organism, the genus name has to be capitalized.
- While these concepts have variations in their fields, the following terms have been overlapping used with taxonomy - systematic biology, systematics, biosystematics, scientific classification, biological classification, and phylogenetics.
- Carl Linnaeus is credited with creating the modern taxonomy.