Question

What is the phenetic species concept?

Answer 1

The species as we know is the fundamental unit of taxonomic hierarchy. Davis called that species are building bricks in biological classification. The hypermodern species concept was given by Platnick and Ghiselin in 1976. They defined species as ‘firms’ in economic analogy. Major goal of taxonomists is the proper delimitation of species. Current species concepts are : Evolutionary species concept, biological species concept and morphological species concept.

Complete answer:
Evolutionary species concept: According to Simpson “an evolutionary species is a lineage evolving separately from others with its unitary evolutionary role and tendencies”. This definition was given in 1961. To know the evolutionary separation it uses ecological, behavioural, genetic and morphological changes.
Biological species concept: Proposed by Buffon in 1753. According to this concept, species are defined as a sexually interbreeding or potentially interbreeding group of individuals separated from other species by the absence of genetic exchange, that is, by reproductive isolation. The concept has allowed taxonomists to make distinction between sibling species e.g., Drosophila pseudoobscura and D. Persimilis , Gilia tricolor and G. angelensis. Sibling species are those which are morphologically similar but reproductively isolated.
Morphological species concept or classical phenetic species concept : It relies upon the morphological traits. According to David and Heywood, “species are assemblage of individuals with common morphological features and separable from other assemblages by correlated morphological discontinuities in a number of features”.
The concept suggest that:
1. Species are the smallest group that are distinguishable by ordinary means.
2. Species is an easily recognized kind of organism.
3. This is a practical and efficient system for information retrieval in most of the flowering plants.
4. This concept is useful and meaningful even for the hybrid plants.

Note:
The important characters of species are: Morphology: Members of a species resemble one another more than they would resemble with members of other species. Anatomy: The members of a species show complete anatomical similarity. Karyotype: Shape, size, number, of chromosomes is same in all the members. Genetic material: All members of a particular species have similar genetic material. Common ancestry: All members of a species have been derived from a common ancestor. Reproductive isolation: Members of one species are reproductively isolated from members of other species.