Species is the basic & smallest whit of classification which is represented by binomial nomenclature according to ICBN. Two individuals with maximum similarities which can interbred among themselves & produce fertile individual & also can exchange gene are called Species.
A Species concept is a concept that is the production of each individual judgement. According to John Ray (1886), ” Species are groups of plants which can inbreed within their limits of variation”.
There are several concept about species such as-
- Biological Species concept
- Typological species concept
- Phylogenetic Species concept
- Evolutionary species concept
- Ecological Species concept
Bological species concept
According to this Concept, a species are groups of actually or partially interbreed populations which are reproductively isolated from other such groups (Moyen 1942).
Species can also be defined from biological species concept as – Species are groups of plants which inbreed within their limits of variation” – John Ray (1686)
- This concept is not applicable for Fossil Species.
- Reproductive isolation is not applicable in case of vegetatively reproduced Species.
- This depends on the ability or inability of Sexual equality.
Typological species concept
According to this Concept, species are categorical entities, distinct and somewhat clearly differentiated (Linnaeus). They share certain characteristics that distinguish them from other species.
Phylogenetic species concept
According to this Concept – Species are a group of organisms that shares a common ancestors and can be distinguished from other species by this.
Evolutionary species concepts
According to this concept – Species can be defined as a single lineage of ancestral descendent population of organisms which maintain its own identity from other such lineages and which has its own evolutionary tendencies and historical fate.
Ecological species concept
Considers a Species to be a lineage which occupies an adaptive zone minimally different from that of any other lineages in its range and which evolved separately from all other lineages outside of its range.