Difference Between Genus And Species

The classification of organisms is the systematic grouping of living things based on characteristics, hierarchical, or phylogenetic relationships. It is one of the major aspects of taxonomy. Organisms are investigated in terms of their morphology, anatomy, physiology, evolution, behavior, development, and genetics in order to find out relationships between and among them. They are then classified into taxonomic groups and into taxonomic hierarchy. The common taxonomic levels are:

  • Domain
  • Kingdom
  • Phyla
  • Class
  • Order
  • Family
  • Genus
  • Species

What Is Genus?

A genus (plural genera) is a taxonomic rank used in the biological classification of living and fossil organisms, as well as viruses in biology. It is usually a major subdivision of a family or subfamily in the classification of organisms, usually consisting of more than one species. In the hierarchy of biological classification, genus comes above species and below family.

Two organisms under same genus may or may not produce a fertilize offspring; organisms from two separate genera cannot produce an offspring that is capable of reproduction. Mule is a classic example of this, it is a product of a male donkey (jack) and a female horse (mare), which are two different species belonging to the same genus (Equus).

In binomial nomenclature, the genus is used as the first word of a scientific name. The genus name is always capitalized and italicized. For example, the binomial name of the lion is Panthera leo. The first part, Panthera, is the genus name whereas the second part, leo, is the specific epithet.

What You Need To Know Genus

  • A genus (plural genera) is a taxonomic rank used in the biological classification of living and fossil organisms, as well as viruses in biology.
  • The word ‘’genus’’, is derived from a Greek word ‘’genus’’ meaning race.
  • A genus consists of a large number of organisms.
  • In the hierarchy of biological classification, genus comes above species and below family.
  • A genus may have several species under it and a number of genera could be from a single family or subfamily.
  • Genus is a singular noun and its plural form is ‘genera’, the genus name of an animal is always written in italics and is the first word in an organism’s scientific name. The first character of the genus name is always capitalized for example, the genus name Homo.
  • Two organisms under a genus may or may not produce a fertilize offspring; organisms from two separate genera cannot produce an offspring that is capable of reproduction. A mule (crossbreed of donkey and horse) is an example.
  • A genus can further be divided into different species.

What Is Species?

A species of organisms is considered as the most basic unit or category in the biological system of classification ranking below a genus. To be considered into a species rank, the group must have at least two of its members capable of reproducing fertile offspring (especially through sexual reproduction).

 Organisms from different species, although they belong under the same genus, generally cannot interbreed as their offspring would likely be infertile. The species of a particular group of organisms would, therefore, pertain to those that can reproduce and sire fertile offspring of the same kind. Thus, they would have the same set of DNA, similar physical and morphological attributes, and demonstrate communal behavior.

The genus-species is the standard format of naming an organism. The genus is the generic name whereas the species is the specific name in a binomial nomenclature. For example, Cupressus nootkatensis (commonly referred to as yellow cedar). The Cupressus is the generic name whereas the nootkatensis is the specific name. Species name is generally written in small letters and in italics.

What You Need To Know Species

  • A species is a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding (producing fertile offspring).
  • The word ‘’Species’’ is derived from a Latin word ‘’specere’’, meaning appearance.
  • A species consists of a few number of organisms.
  • Species is the principal natural taxonomic unit, ranking below a genus.
  • A species may have any number of subspecies or breeds, though they are not usually included when writing or mentioning the organism’s scientific name.
  • The name of the species is the second part of an organism’s scientific name. It is typically written in italics and lowercase letters e.g Homo sapiens.
  • Organisms belonging to same species or subspecies have a high degree of genetic similarity and can interbreed to produce a fertile offspring.  Organisms from separate species under a species genus may or may not be able to reproduce fertile offspring.
  • A species can further be divided into sub-species.

Difference Between Genus And Species In Tabular Form

BASIS OF COMPARISON GENUS SPECIES
Description A genus (plural genera) is a taxonomic rank used in the biological classification of living and fossil organisms, as well as viruses in biology.   A species is a group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding (producing fertile offspring).  
Name Derivation The word ‘’genus’’, is derived from a Greek word ‘’genus’’ meaning race.   The word ‘’Species’’ is derived from a Latin word ‘’specere’’, meaning appearance.  
Number Of Organisms A genus consists of a large number of organisms.   A species consists of a few number of organisms.  
Hierarchy Of Biological Classification In the hierarchy of biological classification, genus comes above species and below family.   Species is the principal natural taxonomic unit, ranking below a genus.  
Species & Subspecies A genus may have several species under it and a number of genera could be from a single family or subfamily.   A species may have any number of subspecies or breeds, though they are not usually included when writing or mentioning the organism’s scientific name.  
Binomial Nomenclature Genus is a singular noun and its plural form is ‘genera’, the genus name of an animal is always written in italics and is the first word in an organism’s scientific name. The first character of the genus name is always capitalized for example, the genus name Homo.   The name of the species is the second part of an organism’s scientific name. It is typically written in italics and lowercase letters e.g Homo sapiens.  
Interbreeding Two organisms under a genus may or may not produce a fertilize offspring; organisms from two separate genera cannot produce an offspring that is capable of reproduction. A mule (crossbreed of donkey and horse) is an example.   Organisms belonging to same species or subspecies have a high degree of genetic similarity and can interbreed to produce a fertile offspring.  Organisms from separate species under a species genus may or may not be able to reproduce fertile offspring.  
Division A genus can further be divided into different species.   A species can further be divided into sub-species.