Introduction to Biosystematics

Taxonomy is mostly concerned with the observation of likeness and variations which exist in the morphology of a huge number of plants. Except it has now been accepted that generally, morphological characters alone are not the criterion for distinctive and classifying plants from one other. One has to acquire into consideration, the characteristics and variations from other disciplines of science like physiology, ecology, cytology, genetics, phytogeography, molecular biology, phytochemistry, numerical taxonomy, breeding systems and any other presented sources for classification.

Biosystematics may be described as 'taxonomy of living populations'. In the current day classification of plants, species is taken like a basic unit and it is the local breeding population. Several disciplines of science thus give countless number of data of all the characters of the individual / a species. This assists to clear problems that are regarding those plants that are different in their classification, interrelationship, and evolution. It gives enough genetic variations which warrant separation so like to recognise them as a separate taxon relies on their evolutionary progress.

Differences in a species may be because of various factors like genetic, ecological, physiological, population dynamic study and several other factors. All the proofs provided through the biosystematics are acquired for analysis and considered through the classical taxonomist to reach any controversial problems that may occurs during their phylogenetic classification relies on their evolution of species under study.

Aims of biosystematics

Camp and Gily in the year 1943, coined the term 'biosystematics'. The aims of biosystematics are as follows.

i) To delimit the naturally taking place biotic community of plant species.

ii) To recognise the several groups as separate biosystematic categories like ecotypes, ecospecies, cenospecies and comparium.

Methods in the study of biosystematics

Three significant methods are as follows.

i) It includes careful sampling analysis of the taxonomic species under study. The population, geographical range, cultivation, cytology, anatomy, palynology, chromosomal number, phytochemistry, and behaviour of it are eagerly observed and studied for finding any genetic variations that may arise between different populations.

ii) It involves determination of capability of dissimilar populations to interbreed between one another to form a variant species with vigor and fertility of it. This will reveal the existence or absence of breeding barriers among taxa at several levels.

iii) It includes the study of likeness of chromosomes in the hybrids throughout meiosis.

Ecotype is the fundamental unit in biosystematics, adapted to a specific environment but able of generating fertile hybrids with other ecotypes. Ecotype is considered as equal to subspecies of classical taxonomy.

Ecospecies is a group of plants having one or more ecotypes in the cenospecies, whose members are capable to interchange their genes. Ecospecies is considered as equal to species of classical taxonomy.

Cenospecies is a group of plants that presenting one or more ecospecies of general evolutionary origin. It is considered as equal to subgenus of classical taxonomy. Cenospecies of similar comparium is separated through genetic barriers and all hybrids among them are sterile.

Comparium is created of one or more cenospecies which is not capable to intercross. Complete genetic barriers present among dissimilar comparia.

The information acquired from the above described studies was compared with the data acquired by comparative morphology and geographical distributions resulted in the identification and recognition of a total range of species. To finish, biosystematics study in the current and modern taxonomy plays a very important role in separating and solving a number of the problems which may develop in the recognition of plants at the level of species. Biosystematist gives all the essential data in solving the real position of species which was in controversy.