**Concept 1: Etymology and History of Genus**
– The term ‘genus’ originates from Latin, related to the concept of bearing or giving birth.
– Carl Linnaeus popularized the term in his 1753 work ‘Species Plantarum.’
– The French botanist Joseph Pitton de Tournefort is credited with founding the modern concept of genera.
– The type concept: Each genus should have a designated type species.
– In zoology, the generic name is linked to the type specimen of its type species.
**Concept 2: Use and Nomenclature of Genus**
– The scientific name of a genus is known as the generic name and is always capitalized.
– It is crucial in binomial nomenclature, where it combines with a species’ name.
– Organisms have a single unique Latin name based on nomenclature codes.
– The scientific name includes the generic name followed by the specific epithet.
– Genus names can be abbreviated when context is clear.
**Concept 3: Classification and Taxonomy of Genus**
– In zoology, names are classified as available or unavailable based on nomenclature rules.
– Taxonomists decide which names are valid, resulting in more available names than valid ones.
– Botanical nomenclature has similar concepts with different labels.
– The type genus forms the base for higher taxonomic ranks.
– Family names like Canidae are based on specific genus names like Canis.
**Concept 4: Identical Names and Homonyms in Genus**
– One generic name can apply to one genus only within the same kingdom.
– Names can unintentionally be assigned to two or more different genera, creating synonyms.
– Homonyms occur when a name means two different things.
– Genus names with the same form but applying to different taxa are called homonyms.
– Examples include Anura, Aotus, Oenanthe, Prunella, and Proboscidea.
**Concept 5: Diversity and Size of Genus**
– Approximately 310,000 accepted genus names may exist out of a total of around 520,000 published names.
– The number of published generic names increases by about 2,500 per year.
– Estimated accepted genus totals by kingdom are provided by Rees et al., 2020.
– Animalia has the highest number of accepted genus names, followed by Plantae, Fungi, Chromista, Protozoa, Bacteria, Archaea, and Viruses.
– The number of species in genera varies significantly among taxonomic groups.
Genus (/ˈdʒiːnəs/ pl.: genera /ˈdʒɛnərə/) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus.
- E.g. Panthera leo (lion) and Panthera onca (jaguar) are two species within the genus Panthera. Panthera is a genus within the family Felidae.
The composition of a genus is determined by taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful:
- monophyly – all descendants of an ancestral taxon are grouped together (i.e. phylogenetic analysis should clearly demonstrate both monophyly and validity as a separate lineage).
- reasonable compactness – a genus should not be expanded needlessly.
- distinctness – with respect to evolutionarily relevant criteria, i.e. ecology, morphology, or biogeography; DNA sequences are a consequence rather than a condition of diverging evolutionary lineages except in cases where they directly inhibit gene flow (e.g. postzygotic barriers).
Moreover, genera should be composed of phylogenetic units of the same kind as other (analogous) genera.