World Earth has numerous habitats with a wide range of living organisms inhabiting them. Plants and animals are present in almost all the places, from polar icecaps to volcanic hot springs, from shallow lagoons to the deepest oceans, from tropical rain forests to dry and parched deserts. There are a variety of species that have been adapted successfully to live in diverse ecosystems. XI Std Biology-Zoology Chapter- organisms.
Hence it becomes necessary to device some means and methods to make this possible and this process is called classification . Classification is a process by which things are grouped in convenient categories, based on easily observable characters. The scientific term used for these categories is taxa (taxon–singular). Taxa indicates categories at different levels, for example Kingdom Animalia, includes multicellular animals such as reptiles, mammals, etc.
Based on their characteristics, all living organisms can be classified into different taxa. This science of classification is called taxonomy . External and internal structures along with developmental processes and ecological information of organisms are essential, as they form basis of the taxonomical studies. Hence, characterisation, identification, nomenclature and classification are the scientific stages that are basic to taxonomy.
The basic need for classifications are: • To identify and differentiate closely related species • To know the variation among the species • To understand the evolution of the species • To create a phylogenetic tree among the different groups • To conveniently study living organisms